Wide-speed-range waverider bidirectional flying wing and design method

Abstract

The invention relates to a wide-speed-range waverider two-way flying wing and a design method, belongs to the technical field of wide-speed-range aircrafts, solves the problem that in the prior art, aerodynamic performance defects caused by waverider are not considered, and comprises the steps that S1, a reference flow field is solved; s2, designing an airfoil profile, and constructing an initial airfoil profile; s3, performing appearance parameterization and multi-target constraint optimization on the initial airfoil profile to obtain an optimized airfoil profile; s4, CFD simulation under the transonic / supersonic speed is carried out, and the optimal airfoil profile with the most ideal lift coefficient, lift-drag ratio and shock wave distribution is selected; s5, constructing a two-way flying wing waverider part and a symmetrical two-way flying wing waverider part; s6, constructing a preliminary model of the body of the wide-speed-range waverider bidirectional flying wing; s7, carrying out girdling passivation to obtain an update model of the body of the wide-speed-range waverider bidirectional flying wing; step S8, performing CFD simulation under each mode and multiple working conditions to obtain a simulation result; and S9, calculating the lift-drag ratio based on the obtained simulation result.

Description

Technical Field

[0001] The present invention relates to the technical field of wide-speed range aircraft, and in particular to a wide-speed range waverider bidirectional flying wing and a design method thereof. Background Art

[0002] Existing hypersonic aircraft typically feature a low-aspect-ratio, highly swept waverider forebody-wing combination, designed to achieve a high lift-to-drag ratio at high speeds and extend range. However, these aircraft typically have poor low-speed performance and may require external lift.

[0003] As the functional requirements and performance requirements of aircraft design continue to increase, wide-speed range aircraft that can provide excellent aerodynamic performance in the full speed range are about to emerge; among them, the bidirectional flying wing that can convert between large / small aspect ratio modes has frequently attracted the attention of the academic community and has broad application prospects.

[0004] However, the bidirectional flying wing of the prior art has the following defects in terms of optimization of aerodynamic performance and modal conversion.

[0005] (1) Failure to consider aerodynamic performance defects caused by wave riding

[0006] Existing bidirectional flying-wing designs fail to fully consider the impact of waveriding on aerodynamic performance during low-aspect-ratio mode design. Specifically, bidirectional flying-wing aircraft typically adopt a four-pointed star or diamond layout, which inherently includes four primary angles: two acute and two obtuse. These pointed-nosed aircraft face shock wave displacement issues during supersonic or hypersonic flight due to their pointed shape.

[0007] When flying at a low aspect ratio, the sharp nose of the vehicle (especially the front and rear acute angles and the left and right obtuse angles) cannot effectively occupy the shock cone it generates. This causes the high-pressure gas gathered at the rear of the shock wave and on the lower surface of the vehicle to bypass the side of the vehicle and leak onto the upper surface, resulting in the so-called "overflow" phenomenon. This will lead to a decrease in the available pressure differential lift of the vehicle, a decrease in the lift-to-drag ratio, and a significant reduction in the aerodynamic performance of the vehicle. At the same time, high-pressure leakage makes the design of the ramjet engine intake difficult, making it difficult to obtain fully compressed gas.

[0008] In addition, there are potential defects in the airfoil design in the prior art. In the existing two-way flying wing design, in order to coordinate the geometric structures of the orthogonally arranged wing spars and ribs with each other, it is necessary to constrain the thickness of the airfoil. The specific requirement is that the thickness of each pair of orthogonal airfoils at the intersection should be consistent to ensure that the aircraft has a smooth appearance. However, the above geometric constraints do not take into account the linkage effect of the aerodynamic performance of the two-way flying wing layout, nor can they meet the waveriding principle: under the premise of waveriding, the upper wing surface should be regarded as FCC (Flow Capture Curve), and the lower surface should be regarded as the result of FCC after flow tracking. This shows that the existing airfoil design has the defect of not being able to use the waveriding principle to improve aerodynamic performance.

[0009] (2) Defects in modal conversion

[0010] The existing mode conversion method is to rotate the aircraft 90° around the z-axis (the normal of the aircraft plane passing through the geometric center of the aircraft) during flight, thereby realizing the conversion between the large / small aspect ratio modes of the aircraft.

[0011] This approach is typically achieved through rudder deflection or other control methods. However, in transonic or supersonic flight, this method often causes the aircraft's axis system to deflect significantly relative to the airflow, leading to a decrease in control stability. This is especially true under strong sidewash, which greatly challenges the aircraft's unsteady control performance.

[0012] Moreover, if rudder deflection is used to achieve this rotation, the rudder will rotate about 90° at trans / supersonic speeds, bringing huge aerodynamic forces (torques) to the rudder and tail, increasing the structural strength requirements; and the aircraft's roll, sideslip, and yaw motions are often coupled together (the cross-aerodynamic derivatives are not 0), and large-angle yaw and sideslip will make the aircraft easily out of control and difficult to recover.

[0013] Furthermore, existing modal transition methods maintain the cabin relative to the flight path by rotating the cabin relative to the aircraft's body. This reduces centrifugal overload on the cabin's axis system (non-inertial system) and reduces pilot directional perception issues during the aircraft's modal transition. This undoubtedly adds unnecessary mechanical structure and deadweight, potentially leading to mechanical failure.

[0014] Therefore, the existing modal conversion methods not only have deficiencies in theory, but also face major technical difficulties in practical applications.

[0015] Therefore, there is a need in the art for improved bidirectional flying wing airfoil design and optimization methods, as well as modal conversion methods, to adapt to more complex flight conditions and provide a wide-speed range aircraft with excellent aerodynamic performance and control stability characteristics. Summary of the Invention

[0016] In view of the above problems, the present invention provides a wide-speed range waverider bidirectional flying wing and a design method, which solves the following problems in the prior art.

[0017] 1. The traditional approach of decoupling different speed requirements in the field of wide-speed range aircraft design (such as a waverider forebody + low-speed wing-body combination) has been changed. Instead, the complex requirements are coupled together for design by constructing airfoils under the premise of waveriding.

[0018] 2. A design is proposed that meets the requirements of waveriding in the longitudinal direction and can be used as a flying wing in the transverse direction. It has a high lift coefficient and lift-to-drag ratio at various speeds and modes (for example, 0.8Ma flying wing, 2Ma flying wing, and 6Ma waveriding). It focuses on solving the overflow problem of flow around the pointed body of the traditional two-way flying wing, and enables the engine air intake to be designed on the lower surface of the flying wing to directly absorb the high-pressure gas compressed by the shock wave, thus ensuring the power requirements at supersonic / hypersonic speeds.

[0019] 3. To design the flying wing mode of the aircraft while being compatible with the requirements of the waverider mode, a geometrically constrained airfoil optimization was proposed. The optimized airfoil, verified by CFD, has a lift-to-drag ratio of 32.1323 at transonic speeds and 7.4329 at supersonic speeds, indicating that the aerodynamic performance indicators have not been compromised by accommodating the waverider design.

[0020] 4. In order to adapt to the designed aircraft and solve the rudder control problem of the bidirectional flying wing, a rudder biplane design using the principle of ultrasonic favorable interference is proposed.

[0021] 5. To meet the modal conversion requirements of high-aspect-ratio flying wing / low-aspect-ratio waverider and to address the unsteady control and aerodynamic design issues caused by the "90-degree rotation" modal conversion method of the traditional bidirectional flying wing, a highly flexible and multi-purpose "folding boost-glide trajectory" design, as well as the derived "cat-ear" and "leaf-vein" shaped trajectory clusters, are proposed. These provide an effective solution for all-weather integrated aerospace reconnaissance, defense, and strike, or as a scientific research platform.

[0022] A design method for a wide-speed range waverider bidirectional flying wing according to one embodiment of the present invention includes the following steps:

[0023] Step S1, solving the reference flow field, using the cone as the generating cone, performing CFD simulation to solve the reference flow field, and obtaining the flow parameters of each point in the reference flow field;

[0024] Step S2, performing airfoil design based on the obtained flow parameters of each point in the reference flow field, designing a wide-speed range airfoil of the wide-speed range waverider bidirectional flying wing, and obtaining an initial airfoil to be used as the tail end surface of the waverider body of the bidirectional flying wing;

[0025] Step S3: To achieve the design of a linked upper and lower airfoil for a wide-speed airfoil, the initial airfoil is subjected to geometrically constrained shape parameterization and multi-objective constraint optimization to obtain an optimized airfoil. The optimized airfoil is then included in the airfoil solution set as a candidate airfoil.

[0026] Step S4, selecting several airfoils with smooth shapes from the multiple candidate airfoils in the airfoil solution set, performing CFD simulations at transonic / supersonic speeds, and ultimately selecting the optimal airfoil with the best lift coefficient, lift-to-drag ratio, and shock wave distribution;

[0027] Step S5, using the selected optimal airfoil as the tail end surface of the bidirectional flying wing waverider body, processing to obtain the bidirectional flying wing waverider body and the symmetrical bidirectional flying wing waverider body;

[0028] Step S6, lofting with the bridging curved surface lofting guide line as the guide line, and with the tail end surface of the bidirectional flying wing waverider body and the tail end surface of the symmetrical bidirectional flying wing waverider body as the cross-sectional curve, obtaining the bridging curved surface of the coupled bidirectional flying wing waverider body and the symmetrical bidirectional flying wing waverider body, the bidirectional flying wing waverider body, the symmetrical bidirectional flying wing waverider body, and the bridging curved surface of the coupled waverider body together constituting a preliminary model of the main body of the wide-speed domain waverider bidirectional flying wing;

[0029] Step S7, moving the boundary line of the preliminary model of the body of the wide-speed-domain waverider bidirectional flying wing inward by a distance to perform circumcision to blunt the edge of the body of the wide-speed-domain waverider bidirectional flying wing, thereby obtaining an updated model of the body of the wide-speed-domain waverider bidirectional flying wing;

[0030] Step S8, performing CFD simulations under various modes and multiple working conditions on the updated model of the wide-speed range waverider bidirectional flying wing body to obtain simulation results;

[0031] Step S9: Calculate the lift-to-drag ratio based on the obtained simulation results, and output the updated model of the body of the wide-speed range waverider bidirectional flying wing for use in the manufacturing process.

[0032] Optionally, step S2 further includes: determining an upper wing surface of the wide-speed range airfoil based on a result of free flow tracking of the FCC, and determining a lower wing surface of the wide-speed range airfoil based on a result of flow tracking of the FCC, the upper wing surface and the lower wing surface together constituting an initial airfoil.

[0033] Optionally, step S3 also includes: expressing the left-right symmetrical "double S-bend" shape of the lower wing surface in a rectangular coordinate system through a parametric method, reconstructing the upper wing surface of the wide-speed airfoil using the reference flow field generated by the solution, calculating the curvature change sign, curvature change rate and airfoil relative thickness information of the upper wing surface as a loss function, and performing airfoil optimization to obtain a variety of arched upper wing surfaces of smooth wide-speed airfoils that meet preset requirements, and using the airfoil including the optimized upper wing surface as an alternative airfoil.

[0034] Optionally, step S4 further includes: selecting an airfoil with a relative thickness in the range of 4%-10% from the candidate airfoils to perform CFD simulation at transonic / supersonic speeds.

[0035] Optionally, step S5 specifically includes the following steps:

[0036] Step S5.1, using the selected optimal airfoil as the basic shape as the tail end surface of the waverider body of the bidirectional flying wing;

[0037] Step S5.2, taking the upper surface curve of the optimal airfoil as the FCC, and performing flow tracing on it to obtain the lower surface of the waverider body of the bidirectional flying wing;

[0038] Step S5.3, taking the upper surface curve of the optimal airfoil as the FCC, and performing free flow tracing on it to obtain the upper surface of the waverider body of the bidirectional flying wing;

[0039] Step S5.4, combining the obtained upper surface and lower surface to obtain a bidirectional flying wing waverider body;

[0040] Step S5.5, symmetricizing the obtained bidirectional flying wing waverider body about the vertical plane to obtain a symmetrical bidirectional flying wing waverider body.

[0041] Optionally, step S8 specifically includes the following steps:

[0042] Step S8.1, performing CFD simulation on the updated model of the wide-speed range waverider bidirectional flying wing body in a waverider mode at 6 Ma, including setting atmospheric and flow parameters under the operating condition, and obtaining simulation results for the operating condition;

[0043] Step S8.2, performing CFD simulation on the updated model of the wide-speed range waverider bidirectional flying wing body under the conditions of 0.8 Ma and 2 Ma in the flying wing mode, including setting the atmospheric and flow parameters under the conditions, and obtaining simulation results for the conditions;

[0044] Step S8.3, performing CFD simulation on the updated model of the wide-speed range waverider bidirectional flying wing body in a flying wing mode at low altitude and low speed, including setting the atmospheric and flow parameters under the working condition to obtain the simulation results of the working condition.

[0045] Optionally, step S7 specifically includes the following steps:

[0046] Step S7.1, moving the boundary line of the preliminary model of the body of the wide-speed-range waverider bidirectional flying wing inward by a certain distance to perform circumcision to blunt the edge of the body of the wide-speed-range waverider bidirectional flying wing, thereby obtaining the preliminary model of the body of the wide-speed-range waverider bidirectional flying wing after circumcision;

[0047] Step S7.2, setting rudder wings and symmetrical differential / linked rudder wings on the top surface of the preliminary model of the body of the wide-speed domain waverider bidirectional flying wing after circumcision. The rudder wings and the differential / linked rudder wings have the same structure and are symmetrically set, thereby obtaining an updated model of the body of the wide-speed domain waverider bidirectional flying wing.

[0048] Optionally, step S7.2 further includes: providing three hydraulic lifting mechanisms below the rudder wings and the differential / linked rudder wings, respectively, to control the lifting and deflection of the rudder surfaces of the rudder wings and the differential / linked rudder wings, respectively.

[0049] According to another embodiment of the present invention, a wide-speed-range waverider bidirectional flying wing is provided, which converts between a waverider mode and a flying wing mode: in the waverider mode, the wide-speed-range waverider bidirectional flying wing moves along the extension direction of the line connecting the wingtip fillets of the bidirectional flying wing waverider body and the symmetrical bidirectional flying wing waverider body, and has a small aspect ratio; in the flying wing mode, the wide-speed-range waverider bidirectional flying wing moves along the extension direction of the axis of symmetry of the bidirectional flying wing waverider body and the symmetrical bidirectional flying wing waverider body, and has a large aspect ratio.

[0050] Compared with the prior art, the wide-speed range waveriding bidirectional flying wing and design method provided by the present invention have at least the following beneficial effects.

[0051] 1. The bidirectional flying wing adopts a waverider design, which enables the aircraft to have a higher lift-to-drag ratio than traditional pointed-body aircraft when flying in a small aspect ratio waverider mode. In addition, the high pressure behind the wave is concentrated on the lower surface of the aircraft, which is conducive to the design of the air intake and the arrangement of the variable cycle engine.

[0052] 2. In order to integrate waveriding design and flying wing design, an airfoil optimization workflow under the premise of waveriding was developed. On the basis of the traditional airfoil optimization dominated by aerodynamic simulation and constrained by aerodynamic performance, geometric constraints with strong correlation between the upper and lower wing surfaces were added.

[0053] 3. The waverider-flying-wing dual-mode joint design enables the flight envelope of this type of aircraft to cover a wider speed range, from subsonic to hypersonic speeds. The waverider design and the variable cycle engine used for this purpose broaden the flight envelope of traditional aircraft.

[0054] 4. It breaks the inherent idea of ​​decoupling designs for different speeds (such as waverider forebody + wing-body combination) in the past. By adding geometrically constrained airfoil optimization, the waverider design suitable for supersonic / hypersonic speeds and the flying wing design suitable for subsonic / transonic / supersonic speeds are fully coupled.

[0055] 5. The proposed modal conversion method avoids aerodynamic and control problems.

[0056] 6. To adapt to the proposed modal conversion method, a series of trajectory designs, such as the "cat ear" shaped trajectory and the "leaf vein" shaped trajectory cluster, have been proposed, which provide improved performance and effects for hypersonic aircraft in autonomous take-off and landing, payload recovery, test platform construction, reconnaissance and strike, etc.

[0057] 7. The proposed "rudder double wing" applies the principle of supersonic favorable interference and provides an improved rudder surface arrangement for bidirectional flying wing aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. By referring to the drawings, the features and advantages of the present invention can be more clearly understood. The drawings are schematic and should not be understood as limiting the present invention in any way. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0059] Figure 1 It is a schematic diagram of the aerodynamic layout of a wide-speed range waverider bidirectional flying wing provided according to the first embodiment of the present invention.

[0060] Figure 2 It is a flow chart of a design method of a wide-speed range waverider bidirectional flying wing provided according to a second embodiment of the present invention.

[0061] Figure 3 1 is a schematic diagram of the geometric constraints of the Fourier series of the lower wing surface in an example of the design method of a wide-speed range waverider bidirectional flying wing provided by the second embodiment of the present invention.

[0062] Figure 4 Schematic diagrams of 12 alternative airfoils obtained by simulated annealing optimization in an example of a design method for a wide-speed range waverider bidirectional flying wing provided by the second embodiment of the present invention.

[0063] Figure 5 This is a CFD simulation flow diagram of a flying wing in the stratosphere at 6Ma and α=5° waveriding mode in an example of the design method of a wide-speed range waveriding bidirectional flying wing provided by the second embodiment of the present invention.

[0064] Figure 6 This is a CFD simulation flow diagram of a flying wing modal in the stratosphere at 2Ma and α=5° in an example of the design method of a wide-speed range waverider bidirectional flying wing provided by the second embodiment of the present invention.

[0065] Figure 7This is a CFD simulation flow diagram of a flying wing mode in the stratosphere at 0.8 Ma and α=1.5° in an example of a design method for a wide-speed range waverider bidirectional flying wing provided by the second embodiment of the present invention.

[0066] Figure 8 This is an example of applying the design method of a wide-speed range waverider bidirectional flying wing provided by the second embodiment of the present invention, in which Opt10 is finally derived from four preferred airfoils for CFD simulation and flow diagrams.

[0067] Figure 9a 3 is a schematic diagram of flow tracking of a wide-speed range waverider bidirectional flying wing in an example of applying the design method of a wide-speed range waverider bidirectional flying wing provided by the second embodiment of the present invention.

[0068] Figure 9b It is a schematic diagram of the lower surface of the waverider body of the wide-speed range waverider bidirectional flying wing obtained by flow tracing streamline lofting of the wide-speed range waverider bidirectional flying wing in an example of the design method of the wide-speed range waverider bidirectional flying wing provided by the second embodiment of the present invention.

[0069] Figure 9c This is a schematic diagram of an example of a design method for a wide-speed range waveriding bidirectional flying wing provided by a second embodiment of the present invention, in which the upper and lower surfaces of a bidirectional flying wing waverider body are combined and the tail end surface is closed to obtain a bidirectional flying wing waverider body.

[0070] Figure 9d It is a schematic diagram of a bridging surface coupling two waverider bodies obtained by lofting in an example of a design method for a wide-speed range waverider bidirectional flying wing provided by the second embodiment of the present invention.

[0071] Figure 9e 3 is a schematic diagram of the circumferential passivation of a wide-speed range waverider bidirectional flying wing in an example of the design method of a wide-speed range waverider bidirectional flying wing provided by the second embodiment of the present invention.

[0072] Figure 10a A schematic diagram of a local edge of a preliminary model of a body of a wide-speed-range waverider bidirectional flying wing before circumferential cut and passivation is performed in an example of applying the design method of the wide-speed-range waverider bidirectional flying wing provided by the second embodiment of the present invention.

[0073] Figure 10b A schematic diagram of a local edge of a preliminary model of a body of a wide-speed-range waverider bidirectional flying wing after circumferential cut and passivation in an example of a design method for a wide-speed-range waverider bidirectional flying wing provided by a second embodiment of the present invention.

[0074] Figure 11Schematic diagram of the position and structure of the rudder and wings of a flying wing in an example of a wide-speed range waveriding bidirectional flying wing provided by the third embodiment of the present invention.

[0075] Figure 12 1 is a schematic diagram of the flight path (trajectory) of an aircraft in an example of applying a wide-speed range waverider bidirectional flying wing provided by the fourth embodiment of the present invention.

[0076] Reference numerals:

[0077] 1-bidirectional flying wing waverider body, 2-wide speed range airfoil, 3-symmetrical bidirectional flying wing waverider body, 4-bridging surface of coupled waverider body, 5-bridging surface lofting guide line, 6-rudder wings, 7-differential / linked rudder wings, 8-hydraulic jacking mechanism, 9-rudder wing flow slot. DETAILED DESCRIPTION

[0078] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present invention and the features therein can be combined with each other without conflict.

[0079] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0080] The wide-speed range waveriding bidirectional flying wing and its design method according to an embodiment of the present invention are described in detail below with reference to the accompanying drawings.

[0081] like Figure 1 As shown, the aerodynamic layout method of the wide-speed range waverider bidirectional flying wing provided by the first embodiment of the present invention is to first construct a waverider body, i.e., a bidirectional flying wing waverider body portion 1, given a reference flow field, and place the waverider body in the vertical plane (i.e., Figure 1 The symmetrical bidirectional flying wing waverider body 3 is obtained by symmetry along the plane formed by the y-axis and the z-axis in the figure. Then, the two waverider body tail end surfaces 2 are bridged by the smooth bridging curved surface 4 of the coupled waverider body to form a bidirectional flying wing with a nearly rounded rhombus shape, wherein the guide line of the lofted curved surface used for bridging is the bridging curved surface lofting guide line 5. The wide-speed range waverider bidirectional flying wing can be moved along the small aspect ratio direction ( Figure 1 ±x direction) wave riding flight; at sub / trans / supersonic speed, after mode conversion, along the direction of large aspect ratio ( Figure 1 ± z direction) in a flying wing configuration. It should be understood that Figure 1The positions of the two-way flying wing waverider body 1 and the symmetrical two-way flying wing waverider body 3 shown in the figure are set for the purpose of explanation and understanding. In another embodiment, their positions can be exchanged, that is, they can be Figure 1 The waverider body on the middle right serves as a bidirectional flying wing waverider body, while the waverider body on the left in the figure serves as a symmetrical bidirectional flying wing waverider body.

[0082] refer to Figures 1 to 10b , a design method for a wide-speed range waveriding bidirectional flying wing provided by a second embodiment of the present invention is described, and the design method includes the following steps.

[0083] Step S1, cone hypersonic CFD, solves the reference flow field, performs CFD simulation (computational fluid dynamics simulation) to solve the reference flow field, and obtains the flow parameters of each point in the reference flow field. The flow field is post-processed to obtain the radial offset of the streamline at any point in the flow field relative to the front of the shock wave, for subsequent reconstruction of the airfoil. Specifically, it includes selecting a cone as a shock wave generator, setting simulation conditions and environmental parameters, performing CFD simulation to obtain simulation results, and using a discrete phase model (DPM) to inject massless particles into the simulation results for flow tracking to obtain the motion trajectory of the particles, and interpolating the radial offset of the particles in the entire flow field to obtain the flow parameters of each point in the reference flow field.

[0084] Step S2, based on the obtained flow parameters of each point in the reference flow field, airfoil design is performed to design the wide-speed range airfoil of the wide-speed range waverider bidirectional flying wing, that is, the cross-sectional shape of the tail end surface 2 of the bidirectional flying wing waverider body 1, to obtain the initial airfoil. Figure 9a As shown, it specifically includes determining the upper surface of the wide-speed range airfoil based on the results of free-flow tracing the FCC (Flow Capture Curve), and determining the lower surface of the wide-speed range airfoil based on the results of flow tracing the FCC. In the flying wing mode, the cross-section of the tail end surface of the waverider body of the bidirectional flying wing is the airfoil of the wide-speed range waverider bidirectional flying wing, which is largely related to the aerodynamic performance of the wide-speed range waverider bidirectional flying wing; in the waverider mode, this cross-section is also the tail end surface of the waverider body, complying with the waverider design requirements. Therefore, the upper surface of the wide-speed range airfoil is the FCC (Flow Capture Curve), and the lower surface is the result of the FCC after flow tracing.

[0085] Step S3, in order to realize the design of the upper and lower wing surfaces of the wide speed range airfoil, the initial airfoil is subjected to the geometry constraint-based shape parameterization and multi-objective constraint optimization to obtain the optimized airfoil, and the optimized airfoil is included in the airfoil solution set (database) as an alternative airfoil. Figure 3As shown, specifically, the method includes expressing the left-right symmetrical "double S-bend" shape of the lower wing surface in a rectangular coordinate system through the Fourier series, reconstructing the upper wing surface of the wide-speed domain airfoil 2 using the reference flow field (for example, a conical 6Ma hypersonic flow field) solved by step S1, calculating the curvature change sign, curvature change rate, relative thickness of the airfoil and other data of the upper wing surface as a loss function, and performing airfoil optimization to obtain a variety of smooth arched upper wing surfaces of the wide-speed domain airfoil 2 that meet the preset requirements, and using the airfoil including the upper wing surface obtained by the optimization as an alternative airfoil.

[0086] Step S4: Select several airfoils with smooth shapes from the multiple alternative airfoils in the airfoil solution set, perform CFD simulations at transonic and supersonic speeds, and ultimately select the optimal airfoil with the best lift coefficient, lift-to-drag ratio, and shock wave distribution. The criterion for selecting an airfoil with smooth shapes from the alternative airfoils can be to select an airfoil whose relative thickness (i.e., maximum thickness divided by chord length) meets set requirements. For example, an airfoil with a relative thickness in the range of 4%-10% and a small upper surface undulation can be selected to avoid the generation of strong shock waves at transonic speeds. The upper surface undulation of the upper airfoil can be evaluated by calculating data such as the curvature change sign and curvature change rate of the upper airfoil as a loss function.

[0087] Step S5, using the selected optimal airfoil as the basic shape as the tail end surface of the bidirectional flying wing waverider body 1, and using the upper airfoil curve of the optimal airfoil as the FCC, performing flow tracing on it to obtain the lower surface of the bidirectional flying wing waverider body 1, and using free flow tracing on it (that is, the upper airfoil curve of the optimal airfoil as the FCC) to obtain the upper surface of the bidirectional flying wing waverider body 1, combining the upper surface and the lower surface to obtain the bidirectional flying wing waverider body 1, and the obtained bidirectional flying wing waverider body 1 is oriented with respect to the vertical plane (that is, Figure 1 The above flow tracking follows the traditional waverider construction method. Figure 9b and Figure 9c , step S5 specifically includes the following steps.

[0088] Step S5.1: Using the selected optimal airfoil as the basic shape as the tail end surface of the bidirectional flying wing waverider body 1.

[0089] Step S5.2: The upper surface curve of the optimal airfoil is used as the FCC, and flow tracing is performed on it to obtain the lower surface of the bidirectional flying wing waverider body 1.

[0090] Step S5.3: The upper airfoil curve of the optimal airfoil is used as FCC, and free flow tracing is performed on it to obtain the upper surface of the bidirectional flying wing waverider body 1.

[0091] Step S5.4, combining the obtained upper surface and lower surface to obtain the bidirectional flying wing waverider body 1.

[0092] Step S5.5, symmetric the obtained bidirectional flying wing waverider body 1 about the vertical plane to obtain a symmetrical bidirectional flying wing waverider body 3.

[0093] Step S6, as Figure 9d As shown, the bridging surface lofting guide line 5 is used as the guide line, and the tail end surface of the bidirectional flying wing waverider body 1 and the tail end surface of the symmetrical bidirectional flying wing waverider body 3 are used as cross-sectional curves for lofting, and the bridging surface 4 of the coupled bidirectional flying wing waverider body 1 and the symmetrical bidirectional flying wing waverider body 3 is obtained. The bidirectional flying wing waverider body 1, the symmetrical bidirectional flying wing waverider body 3, and the bridging surface 4 of the coupled waverider part together constitute a preliminary model of the main body of the wide-speed range waverider bidirectional flying wing.

[0094] See also Figure 9d , it is shown that a symmetrical bidirectional flying wing waverider body is obtained by making the bidirectional flying wing waverider body symmetrical about the vertical plane, and the bridging surface lofting guide line is used as the guide line, and the tail end surface of the bidirectional flying wing waverider body and the tail end surface of the symmetrical bidirectional flying wing waverider body are used as cross-sectional curves for lofting to obtain the bridging surface of the coupled bidirectional flying wing waverider body and the symmetrical bidirectional flying wing waverider body.

[0095] Step S7, the boundary line of the preliminary model of the body of the wide-speed domain waverider bidirectional flying wing is moved inward by a distance to perform circumcision, so as to blunt the edge of the body of the wide-speed domain waverider bidirectional flying wing and obtain an updated model of the body of the wide-speed domain waverider bidirectional flying wing. The distance of the inward movement can be set as needed. The processing of this step can facilitate CFD simulation of the obtained model, specifically, facilitate the generation of boundary layers at the edges; and solve the problem of aerodynamic heating. Figure 9e , Figure 10a and Figure 10b As shown, in the preliminary model of the body of a wide-speed waverider bidirectional flying wing, its edges have no thickness, and the upper and lower surfaces converge into a single line, the leading edge line. In high-speed flow, this area can produce severe aerodynamic heating, which can lead to simulation failure and pose challenges to the thermal protection of the actual aircraft structure. Therefore, this step appropriately shifts the boundary of the preliminary model inward to form a small-thickness annular surface, replacing the zero-thickness leading edge line. This acts as a passivation, facilitating the drawing of several layers of mesh at the formed annular surface and avoiding meshing errors. It also slightly detaches the local shock wave from the body, isolating the heat and mitigating the adverse effects of aerodynamic heating.

[0096] Step S8, performs CFD simulation on the updated model of the body of the wide-speed domain waveriding bidirectional flying wing obtained in various modes and multiple working conditions to obtain simulation results. The obtained simulation results may include lift, drag, flow field, etc. Optionally, the updated model of the body of the wide-speed domain waveriding bidirectional flying wing obtained can be subjected to CFD simulation under three working conditions: flying in a flying wing mode at 0.8Ma and 2Ma, and flying in a waveriding mode at 6Ma. Alternatively, this step may also include performing CFD simulation on a working condition of flying at low altitude and low speed (for example, an altitude of 0m, a static temperature of 288K, a static pressure of 1atm, and a Mach number of 0.3Ma). This step S8 specifically includes the following steps.

[0097] Step S8.1 performs a CFD simulation on the updated model of the wide-speed range waverider bidirectional flying wing body in waverider mode at 6 Ma, including setting atmospheric and flow parameters for this operating condition and obtaining simulation results for this operating condition. This parameter setting may include setting altitude, temperature, and pressure as needed. Static temperature and static pressure can be obtained from a table, the Mach number and angle of attack can be set as needed, and the Reynolds number can be calculated based on the air viscosity coefficient and density obtained from the simulation results.

[0098] Step S8.2, performing CFD simulation on the updated model of the wide-speed range waverider bidirectional flying wing body under the flying wing mode at 0.8Ma and 2Ma, including setting the atmospheric and flow parameters under the working conditions, and obtaining the simulation results of the working conditions.

[0099] Step S8.3, performing CFD simulation on the updated model of the wide-speed range waverider bidirectional flying wing body in a flying wing mode at low altitude and low speed, including setting the atmospheric and flow parameters under the working condition to obtain the simulation results of the working condition.

[0100] Step S9 calculates the lift-to-drag ratio based on the simulation results and evaluates whether it meets the design expectations. The simulation results can also be further analyzed using fluid dynamics principles. The updated model of the wide-speed range waverider bidirectional flying wing is then output for use in the manufacturing process.

[0101] Example 1

[0102] The following references Figures 1 to 10b , Example 1 of the design method of a wide-speed range waverider bidirectional flying wing according to the second embodiment of the present invention is described.

[0103] The design method of the wide-speed range waveriding bidirectional flying wing of Example 1 specifically includes the following steps.

[0104] Step S1: Cone hypersonic CFD solves the benchmark flow field. Using the CFD software Fluent, a cone with a 6° half-apex angle is selected as the shock wave generator. The simulation conditions are set to 6 Ma zero angle of attack flow, and the environmental parameters are set to a true pressure of 5000 Pa and a true temperature of 220 K at an altitude of 20 km. After the simulation, a discrete phase model (DPM) is used to inject massless particles for flow tracking and interpolate the flow parameters at each point in the benchmark flow field.

[0105] Step S2, airfoil design, determines the upper surface of the wide-speed range airfoil based on the results of the FCC (Flow Capture Curve) after free flow tracking, and determines the lower surface of the wide-speed range airfoil based on the results of the FCC after flow tracking, to obtain the tail end cross-sectional shape of the bidirectional flying wing waverider body 1.

[0106] Step S3, using the Fourier series to express the bilaterally symmetrical "double S-bend" shape of the lower wing in a rectangular coordinate system, using the previously solved generating cone 6Ma hypersonic flow field to reconstruct the upper wing surface of the wide-speed range airfoil 2, calculating the curvature change sign, curvature change rate, relative thickness and other data of the upper wing surface as a loss function, and performing airfoil optimization to obtain 12 types of smooth arched upper wing surfaces of the wide-speed range airfoil 2 that meet the preset requirements, such as Figure 4 As shown, the optimized airfoil is used as an alternative airfoil.

[0107] Step S4: Select four airfoils with a relative thickness close to 4% and a smooth appearance from the 12 optimized alternative airfoils, perform CFD simulations at transonic / supersonic speeds, and ultimately select the optimal airfoil Opt10 with the best lift coefficient, lift-to-drag ratio, and shock wave distribution. Figure 8 .

[0108] Step S5, using the selected optimal airfoil Opt10 as the basic shape as the tail end surface of the bidirectional flying wing waverider body 1, the upper airfoil curve of the airfoil as the FCC, using the conventional waverider body construction method to perform flow tracking on it to obtain the lower surface of the bidirectional flying wing waverider body 1, using free flow tracking to obtain the upper surface of the bidirectional flying wing waverider body 1, combining the upper surface and the lower surface to obtain the bidirectional flying wing waverider body 1, and symmetrizing the obtained bidirectional flying wing waverider body 1 about the flow direction to obtain a symmetrical bidirectional flying wing waverider body 3.

[0109] Step S6, using the bridging surface lofting guide line 5 as the guide line, and using the tail end surface of the bidirectional flying wing waverider body 1 and the tail end surface of the symmetrical bidirectional flying wing waverider body 3 as the cross-sectional curves for lofting, to obtain the bridging surface 4 of the coupled bidirectional flying wing waverider body 1 and the symmetrical bidirectional flying wing waverider body 3. The bidirectional flying wing waverider body 1, the symmetrical bidirectional flying wing waverider body 3, and the bridging surface 4 of the coupled waverider part together constitute a preliminary model of the main body of the wide-speed range waverider bidirectional flying wing.

[0110] Step S7: Move the boundary line of the preliminary model of the wide-speed domain waverider bidirectional flying wing body inward by a distance to perform circumcision to blunt the edge of the wide-speed domain waverider bidirectional flying wing body, and obtain an updated model of the wide-speed domain waverider bidirectional flying wing body.

[0111] Step S8, performing CFD simulations on the updated model of the wide-speed range waverider bidirectional flying wing under various modes and multiple working conditions to obtain simulation results, such as Figures 5 to 7 As shown. Among them, the parameters of the CFD simulation under the working condition of 6Ma in waverider mode are set as altitude = 20km, pressure = 5000Pa, temperature = 220K, angle of attack α = 5°, and waverider mode simulation (Reynolds number Re = 86097986); the waverider mode simulation results under this working condition are obtained. The parameters of the CFD simulation under the working condition of 2Ma in flying wing mode are set as altitude = 11km, pressure = 20000Pa, temperature = 217.15K, angle of attack α = 5°, and Reynolds number Re = 117077340, and the parameters of the CFD simulation under the working condition of 0.8Ma are set as angle of attack α = 1.5° and Re = 46686122; the flying wing mode simulation results of the two working conditions are obtained.

[0112] Step S9, based on the obtained simulation results, a judgment is made. In the first embodiment, the obtained wide-speed range waverider bidirectional flying wing has a lift coefficient of 0.0612, a drag coefficient of 0.0091, a lift-to-drag ratio K=6.7005, and a longitudinal flow as follows: Figure 5 As shown in Figure 2, this lift-to-drag ratio breaks the so-called "lift-to-drag ratio barrier", reflecting the advantages of the obtained wide-speed range waverider bidirectional flying wing over the conventional configuration in hypersonic speed; under the flying wing mode simulation, the obtained wide-speed range waverider bidirectional flying wing has a lift coefficient of 0.1936 and a drag coefficient of 0.0291 when flying under the 2Ma working condition; the lift-to-drag ratio K = 6.6496, and the longitudinal flow is as follows: Figure 6 As shown in the figure, the lift coefficient of the wide-speed waverider bidirectional flying wing is 0.1799 at 0.8 Ma, the drag coefficient is 0.0108, the lift-to-drag ratio K is 16.6016, and the longitudinal flow is as follows: Figure 7 shown.

[0113] Unlike (hyper)sonic flow, in transonic flow, the trailing edge camber created by the bridging curved surface in step S6 improves moment characteristics to a certain extent, increasing the nose-up moment and reducing the trim pressure on the control surfaces. Therefore, in a flying wing design with insufficient tail lever or no tail, a wing with this trailing edge camber profile can achieve longitudinal static stability.

[0114] The wide-speed range waverider bidirectional flying wing configuration designed by the design method of the wide-speed range waverider bidirectional flying wing provided in the second embodiment has a small RCS (radar cross section) and can also provide the advantage of electromagnetic stealth.

[0115] The bi-symmetrical design of a bidirectional flying wing has poor static and dynamic stability in both longitudinal and lateral directions, and therefore relies heavily on the flight control system to calculate flight attitude and compensate for the control of the control surfaces. However, the difficulty in arranging the control surfaces lies in the following: if the elevators and drag rudders of a traditional flying wing are deployed in flying wing mode, the lever arm will inevitably be insufficient; the hinge axis of the control surface is parallel to the flight direction in waverider mode, making it difficult to control in waverider mode; in addition, the skin defects and exposed gaps caused by the rudder surface arrangement will undermine stealth and thermal insulation capabilities, and the remaining actuators will also affect the flight resistance in the other direction.

[0116] like Figure 11 As shown, in order to solve the above-mentioned problems and realize a wide-speed range waverider bidirectional flying wing with better control performance, a third embodiment of the present invention provides a design method for a wide-speed range waverider bidirectional flying wing. On the basis of the above second embodiment, it also includes the step of providing a rudder biplane on the upper wing surface to generate a lift-drag difference on both sides, thereby forming an actuating torque. In this embodiment, the principle of supersonic favorable interference can be utilized, or reference can be made to methods such as parasol wings to capture the interference lift generated by the reflection of the pointed body shock wave under the wing. It can be seen that an appropriate biplane design can exhibit good lift-drag characteristics at various speeds. The third embodiment provides a wide-speed range waverider bidirectional flying wing with a rudder biplane design that adopts differential / linked actuation on both sides.

[0117] Continue to refer Figure 11 Specifically, the design method of the wide-speed range waveriding bidirectional flying wing provided by the third embodiment includes the same steps as steps S1 to S6 and steps S8 to S9 of the above second embodiment, which will not be repeated here. In addition, in this embodiment, step S7 specifically includes the following steps.

[0118] Step S7.1, moving the boundary line of the preliminary model of the body of the wide-speed domain waverider bidirectional flying wing inward by a certain distance to perform circumferential cutting to blunt the edge of the body of the wide-speed domain waverider bidirectional flying wing, and obtaining the preliminary model of the body of the wide-speed domain waverider bidirectional flying wing after circumferential cutting.

[0119] Step S7.2, arranging rudder wings 6 and differential / linked rudder wings 7 on the top surface of the preliminary model of the body of the wide-speed waveriding bidirectional flying wing after circumcision, the rudder wings 6 and the differential / linked rudder wings 7 have the same structure and are symmetrically arranged. Optionally, this step may also include arranging three hydraulic lifting mechanisms 8 below the structures of the rudder wings 6 and the differential / linked rudder wings 7, respectively, to control the lifting and deflection of the rudder wings 6 and the differential / linked rudder wings 7. When the hydraulic lifting mechanisms 8 control the lifting and deflection of the rudder wings 6 and the differential / linked rudder wings 7, a rudder wing flow slot 9 is formed below the rudder wings 6 and the differential / linked rudder wings 7. As shown in FIG. Figure 11 As shown, the positions of the rudder wings 6 and the differential / linked rudder wings 7 can be set to correspond to the positions of the bidirectional flying-wing waverider body 1 and the symmetrical bidirectional flying-wing waverider body 3 of the preliminary model after ring cutting. If necessary, the rudder wings 6 and the differential / linked rudder wings 7 can be set so that they are located within the position range of the bidirectional flying-wing waverider body 1 and the symmetrical bidirectional flying-wing waverider body 3; in other cases, the rudder wings 6 and the differential / linked rudder wings 7 can also be set so that they extend to the range of the bridge curved surface 4.

[0120] like Figure 11 The rudder wings 6 and the differential / linked rudder wings 7 shown in FIG can utilize the difference in aerodynamic forces (moments) to achieve pitch, roll, and yaw operations. Figure 11 The rudder wings 6 and the differential / linked rudder wings 7 are each controlled by three hydraulic lift mechanisms 8. These mechanisms ensure the rudder surfaces can be raised and deflected as needed, compensating for the insufficient rudder deflection arm in the horizontal plane with vertical displacement. Simultaneously, the rudder wing flow channels 9 created by the raised rudder wings 6 and differential / linked rudder wings 7 also provide flow regulation and maneuvering. This wide-range waverider bidirectional flying wing system achieves effective control in both directions, and because the rudder deflection is minimal during high-speed flight, the hydraulic component strength requirements are low.

[0121] Continue to refer Figure 1The wide-speed-range waverider bidirectional flying wing designed by the design method of the wide-speed-range waverider bidirectional flying wing provided by the second embodiment according to the fourth embodiment of the present invention comprises: a bidirectional flying wing waverider body 1; a symmetrical bidirectional flying wing waverider body 3 having the same structure as the bidirectional flying wing waverider body 1 and symmetrically arranged with respect to the bidirectional flying wing waverider body 1; and a bridging curved surface 4 of the coupled waverider body, which bridges the bidirectional flying wing waverider body 1 and the symmetrical bidirectional flying wing waverider body 3 together. The bridging curved surface 4 of the coupled waverider body is obtained by lofting the tail end surfaces of the bidirectional flying wing waverider body 1 and the symmetrical bidirectional flying wing waverider body 3 using the bridging curved surface lofting guide line 5 as a guide line. When the wide-speed range waverider bidirectional flying wing uses the rounded corners of the bidirectional flying wing waverider body 1 or the rounded corners of the symmetrical bidirectional flying wing waverider body 3 as the forward head of the aircraft, it has a small aspect ratio and is a waverider mode; when the bidirectional flying wing waverider body 1 and the symmetrical bidirectional flying wing waverider body 3 are used as the wings on both sides of the aircraft, it has a large aspect ratio and is a flying wing mode.

[0122] The wide-speed waveriding bidirectional flying wing provided in the fourth embodiment can be converted between the waveriding mode and the flying wing mode: in the waveriding mode, the wide-speed waveriding bidirectional flying wing is rotated along the extension direction of the line connecting the wingtip fillets of the bidirectional flying wing waverider body 1 and the symmetrical bidirectional flying wing waverider body 3 (i.e. Figure 1 ±x direction in the flying wing) and has a small aspect ratio; in the flying wing mode, the wide speed range waverider bidirectional flying wing moves along the extension direction of the symmetry axis of the bidirectional flying wing waverider body 1 and the symmetrical bidirectional flying wing waverider body 3 (i.e. Figure 1 ±z direction) and has a large aspect ratio.

[0123] Optionally, the wide-speed-range waveriding bidirectional flying wing of this embodiment may further include the rudder wings 6 and the differential / linked rudder wings 7 designed by the design method of the wide-speed-range waveriding bidirectional flying wing provided in the third embodiment.

[0124] like Figure 12 As shown, based on the modal conversion characteristics of a wide-speed range waverider bidirectional flying wing, in order to adapt to unmanned positioning of a loitering missile or an aerial test platform, a fifth embodiment of the present invention provides a modal conversion method for a wide-speed range waverider bidirectional flying wing, including setting a sideslip-dominated modal conversion trajectory, specifically comprising the following steps:

[0125] Step S0: Constructing a wide-speed-range waveriding bidirectional flying wing. In this step, the design method of the wide-speed-range waveriding bidirectional flying wing provided in the second embodiment or the third embodiment can be used to construct the wide-speed-range waveriding bidirectional flying wing.

[0126] Step S1: The trajectory of the wide-speed range waverider bidirectional flying wing is divided into a takeoff phase, a climb phase, a power boost phase, an inertial ascent phase, a trajectory apex, and a sideslip phase. The trajectory apex is the mode transition phase, and the sideslip phase is the dive phase of the waverider mode. The boost-glide trajectory is used as the basis, and a near-right angle is designed at the trajectory apex.

[0127] Step S2: Control the wide-speed range waverider bidirectional flying wing to a high-aspect-ratio flying wing mode during the climb phase, starting from horizontal takeoff or separation from another aircraft, accelerate to within Mach 2, and climb to the stratosphere (e.g., approximately 20 km or higher), which is called the flying wing cruising altitude.

[0128] Step S3: Control the wide-speed range waverider bidirectional flying wing to climb from the cruising altitude to the near-space at a large track inclination angle in the power boost phase until the engine efficiency drops significantly.

[0129] Step S4, then the wide-speed range waverider bidirectional flying wing enters the inertial ascent phase, controls the engine of the wide-speed range waverider bidirectional flying wing to shut down, and the wide-speed range waverider bidirectional flying wing maintains unpowered ascent until it reaches the trajectory apex.

[0130] Step S5: Control the wide-speed waverider bidirectional flying wing to enter a modal transition section near the trajectory apex. At this time, the speed of the wide-speed waverider bidirectional flying wing is substantially reduced to zero, and the engine, the air inlet, and the compressor of the wide-speed waverider bidirectional flying wing are unlocked. The wing is rotated 90 degrees relative to the fuselage, aligned with the waverider direction, and locked with the waverider ramjet inlet.

[0131] Step S6: The wide-range waverider bidirectional flying wing is controlled to slope sideways to enter a sideslip phase (the wing mode of the wide-range waverider bidirectional flying wing is sideslip, while the waverider mode is a dive). The engine is re-ignited using compressed gas or other means. After a period of acceleration, the dynamic pressure required for the engine ramjet is achieved. The wide-range waverider bidirectional flying wing is then leveled and rapidly accelerated to near the waverider design point of 6 Ma. It then maintains gliding flight in the waverider mode, followed by a strike or a connected recovery trajectory. This connected recovery trajectory can form a "cat-ear" takeoff and landing trajectory.

[0132] See also Figure 12The boost-glide trajectory described above doesn't refer to a single trajectory, but rather a cluster of trajectories shaped like leaf veins. The main vein is the high-aspect-ratio flying wing mode flight segment of the wide-speed waverider bidirectional flying wing, while the secondary veins branching off from the main vein are the waverider mode flight segments. This trajectory cluster design, combined with the wing's inherent superior maneuverability compared to a missile, allows for greater flexibility in trajectory design. The wide-speed waverider bidirectional flying wing can "patrol without striking" for deterrence or reconnaissance. By docking two folded boost-glide trajectories, a "cat-ear" takeoff and landing trajectory with two apexes can be obtained, allowing the wide-speed waverider bidirectional flying wing to be retracted. Furthermore, one of the "leaf vein" trajectories can be selected for strike. The timing and location of the trajectory's peak, as well as the choice of glide to the left or right, can all be determined temporarily during flight, breaking the constraints of the "launch plane" of traditional trajectory design and further increasing the difficulty of interception.

[0133] If the aforementioned "cat-ear" takeoff and landing trajectory is separated from the waverider glide and landing sections and preceded by a reentry trajectory from Earth transfer orbit, it can also be used for recovering payloads or spacecraft in deep space missions, effectively acting as a space shuttle capable of horizontal landing. Furthermore, the design methods for wide-speed waverider bidirectional flying wings provided by embodiments of the present invention can also be used to design probe configurations for deep space exploration of planets with atmospheres.

[0134] The wide-speed range waverider bidirectional flying wing designed by the design method of the wide-speed range waverider bidirectional flying wing provided by the embodiment described above can adopt a large aspect ratio flying wing mode to fly between 0 and 2 Ma, wherein it may be necessary to use the ground effect to obtain lift during takeoff. After climbing to the cruising altitude of the wide-speed range waverider bidirectional flying wing, if it is necessary to switch to the small aspect ratio waverider mode, it enters Figure 12 The strike trajectory or "cat-ear" take-off and landing trajectory shown in the figure climbs to the apex of the trajectory at a large elevation angle. At this time, the speed is approximately 0, the engine is shut down, and the aircraft rotates 90 degrees relative to the fuselage. Then the aircraft slopes to the left or right (the airspeed is approximately 0 at this time, and the slope cannot be achieved by rudder deflection. It is possible to consider compressed gas as an attitude control engine or the landing gear as a momentum wheel), turns into the waveriding flight direction and enters a dive, and the engine ignites to accelerate.

[0135] After rapidly accelerating to supersonic speed, the wide-speed range waverider bidirectional flying wing automatically balances under the action of aerodynamic torque, flies along the waverider direction at a certain positive angle of attack, and then continues to accelerate to the design point, that is, the theoretical maximum speed of 6Ma.

[0136] In addition, the above theoretical maximum speed of 6 Ma is an example used to verify this design concept. Taking into account the spacecraft re-entry speed and the terminal strike speed of existing hypersonic aircraft, it is reasonable to select this value within the range of 5 to 15 Ma.

[0137] All of the above optional technical solutions can be combined in any way to form optional embodiments of the present application, and will not be described in detail here.

[0138] It should be understood that the order of execution of the steps in the above embodiments does not necessarily mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0139] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed in the present invention should be covered by the scope of protection of the present invention.

Claims

1. A design method for a wide-speed range waverider bidirectional flying wing, characterized in that: The following steps are involved: Step S1, solving the reference flow field, using the cone as the generating cone, performing CFD simulation to solve the reference flow field, and obtaining the flow parameters of each point in the reference flow field; Step S2, performing airfoil design based on the obtained flow parameters of each point in the reference flow field, designing a wide-speed range airfoil of the wide-speed range waverider bidirectional flying wing, and obtaining an initial airfoil to be used as the tail end surface of the waverider body of the bidirectional flying wing; Step S3: To achieve the design of a linked upper and lower airfoil for a wide-speed airfoil, the initial airfoil is subjected to geometrically constrained shape parameterization and multi-objective constraint optimization to obtain an optimized airfoil. The optimized airfoil is then included in the airfoil solution set as a candidate airfoil. Step S4, selecting several airfoils with smooth shapes from the multiple candidate airfoils in the airfoil solution set, performing CFD simulations at transonic / supersonic speeds, and ultimately selecting the optimal airfoil with the best lift coefficient, lift-to-drag ratio, and shock wave distribution; Step S5, using the selected optimal airfoil as the tail end surface of the bidirectional flying wing waverider body, processing to obtain the bidirectional flying wing waverider body and the symmetrical bidirectional flying wing waverider body; Step S6, lofting with the bridging curved surface lofting guide line as the guide line, and with the tail end surface of the bidirectional flying wing waverider body and the tail end surface of the symmetrical bidirectional flying wing waverider body as the cross-sectional curve, obtaining the bridging curved surface of the coupled bidirectional flying wing waverider body and the symmetrical bidirectional flying wing waverider body, the bidirectional flying wing waverider body, the symmetrical bidirectional flying wing waverider body, and the bridging curved surface of the coupled waverider body together constituting a preliminary model of the main body of the wide-speed domain waverider bidirectional flying wing; Step S7, moving the boundary line of the preliminary model of the body of the wide-speed-domain waverider bidirectional flying wing inward by a distance to perform circumcision to blunt the edge of the body of the wide-speed-domain waverider bidirectional flying wing, thereby obtaining an updated model of the body of the wide-speed-domain waverider bidirectional flying wing; Step S8, performing CFD simulations under various modes and multiple working conditions on the updated model of the wide-speed range waverider bidirectional flying wing body to obtain simulation results; Step S9: Calculate the lift-to-drag ratio based on the obtained simulation results, and output the updated model of the body of the wide-speed range waverider bidirectional flying wing for use in the manufacturing process.

2. The design method of a wide-speed range waverider bidirectional flying wing according to claim 1, characterized in that: Step S2 further includes: determining an upper surface of the wide-speed range airfoil based on the result of free flow tracking of the FCC, and determining a lower surface of the wide-speed range airfoil based on the result of flow tracking of the FCC, the upper surface and the lower surface together forming the initial airfoil.

3. The design method of a wide-speed range waverider bidirectional flying wing according to claim 1, characterized in that: Step S3 also includes: expressing the bilaterally symmetrical "double S-bend" shape of the lower airfoil in a rectangular coordinate system through a parameterized method, reconstructing the upper airfoil of the wide-speed range airfoil using the reference flow field generated by the solution, calculating the curvature change sign, curvature change rate and airfoil relative thickness information of the upper airfoil as a loss function, and performing airfoil optimization to obtain a variety of arched upper airfoils of the wide-speed range that are smooth and meet preset requirements, and using the airfoil including the optimized upper airfoil as an alternative airfoil.

4. The design method of a wide-speed range waverider bidirectional flying wing according to claim 1, characterized in that: Step S4 further includes: selecting an airfoil with a relative thickness in the range of 4%-10% from the candidate airfoils to perform CFD simulation at transonic / supersonic speeds.

5. The design method of a wide-speed range waverider bidirectional flying wing according to claim 1, characterized in that: Step S5 specifically includes the following steps: Step S5.1, using the selected optimal airfoil as the basic shape as the tail end surface of the waverider body of the bidirectional flying wing; Step S5.2, taking the upper surface curve of the optimal airfoil as the FCC, and performing flow tracing on it to obtain the lower surface of the waverider body of the bidirectional flying wing; Step S5.3, taking the upper airfoil curve of the optimal airfoil as the FCC, and performing free flow tracing on it to obtain the upper surface of the waverider body of the bidirectional flying wing; Step S5.4, combining the obtained upper surface and lower surface to obtain a bidirectional flying wing waverider body; Step S5.5, symmetric the obtained bidirectional flying wing waverider body about the vertical plane to obtain a symmetrical bidirectional flying wing waverider body.

6. The design method of a wide-speed range waverider bidirectional flying wing according to claim 1, characterized in that: Step S8 specifically includes the following steps: Step S8.1, performing CFD simulation on the updated model of the wide-speed range waverider bidirectional flying wing body in a waverider mode at 6 Ma, including setting atmospheric and flow parameters under the operating condition, and obtaining simulation results for the operating condition; Step S8.2, performing CFD simulation on the updated model of the wide-speed range waverider bidirectional flying wing body under the conditions of 0.8 Ma and 2 Ma in the flying wing mode, including setting the atmospheric and flow parameters under the conditions, and obtaining simulation results for the conditions; Step S8.3, performing CFD simulation on the updated model of the wide-speed range waverider bidirectional flying wing body in a flying wing mode at low altitude and low speed, including setting the atmospheric and flow parameters under the working condition to obtain the simulation results of the working condition.

7. The design method of a wide-speed range waverider bidirectional flying wing according to claim 1, characterized in that: Step S7 specifically includes the following steps: Step S7.1, moving the boundary line of the preliminary model of the body of the wide-speed-range waverider bidirectional flying wing inward by a certain distance to perform circumcision to blunt the edge of the body of the wide-speed-range waverider bidirectional flying wing, thereby obtaining the preliminary model of the body of the wide-speed-range waverider bidirectional flying wing after circumcision; Step S7.2, setting rudder wings and symmetrical differential / linked rudder wings on the top surface of the preliminary model of the body of the wide-speed domain waverider bidirectional flying wing after circumcision. The rudder wings and the differential / linked rudder wings have the same structure and are symmetrically set, thereby obtaining an updated model of the body of the wide-speed domain waverider bidirectional flying wing.

8. The design method of a wide-speed range waverider bidirectional flying wing according to claim 7, characterized in that: Step S7.2 also includes: setting three hydraulic lifting mechanisms below the rudder wings and the differential / linked rudder wings respectively to control the lifting and deflection of the rudder surfaces of the rudder wings and the differential / linked rudder wings respectively.

9. The wide-speed range waverider bidirectional flying wing designed by the design method of any one of claims 1 to 8 is characterized in that: The wide-speed range waverider bidirectional flying wing switches between the waverider mode and the flying wing mode: In the waverider mode, the wide-speed-range waverider bidirectional flying wing moves along the extension direction of the line connecting the bidirectional flying wing waverider body and the wingtip fillet of the symmetrical bidirectional flying wing waverider body, and has a small aspect ratio; In the flying wing mode, the wide-speed-range waverider bidirectional flying wing moves along the extension direction of the bidirectional flying wing waverider body and the symmetry axis of the symmetrical bidirectional flying wing waverider body, and has a large aspect ratio.

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