A transonic nonlinear aerodynamic correction method
By correcting the aerodynamic model using the dipole lattice method with CFD data, the problems of insufficient accuracy and low efficiency in aerodynamic analysis during transonic flight are solved, and efficient aeroelastic analysis is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA ACAD OF LAUNCH VEHICLE TECH
- Filing Date
- 2022-10-26
- Publication Date
- 2026-05-26
AI Technical Summary
In the aerodynamic analysis of transonic flight, existing technologies suffer from insufficient prediction accuracy of engineering methods and low computational efficiency of CFD methods, making it difficult to balance the requirements of computational accuracy and efficiency.
The aerodynamic model of the dipole lattice method is modified using CFD data. By generating the downwash velocity matrix and correcting the angle of attack, the aerodynamic influence coefficient matrix is improved, thereby enhancing the analysis accuracy and maintaining high efficiency.
A balance between computational accuracy and efficiency was achieved in the aerodynamic analysis of the transonic flight segment, meeting the requirements for rapid iteration in the overall design.
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Figure CN115906685B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of aerospace overall design technology, and relates to an aeroelastic design method for a space-to-ground reusable vehicle, and particularly to a method for correcting acoustic nonlinear aerodynamic forces. Background Technology
[0002] Reusable spacecraft undergo cross-airspace and cross-velocity flight during their operation. In the transonic flight phase, aerodynamic forces exhibit significant nonlinearity, greatly impacting aeroelastic properties. Engineering methods suffer from poor accuracy in this phase and require correction. Specifically, aeroelastic analysis requires aerodynamic forces as input and must balance computational accuracy and efficiency. Engineering aerodynamic models, such as the dipole lattice method, are commonly used for aeroelastic analysis. However, in the transonic flight segment, due to the strongly nonlinear characteristics of aerodynamic forces, engineering methods show significant deviations in prediction accuracy. While CFD methods can accurately describe the nonlinear characteristics of the flow field in the transonic flight segment, their low computational efficiency prevents them from meeting the requirements of rapid iterative overall design. Summary of the Invention
[0003] The purpose of this invention is to overcome the above-mentioned defects and provide a transonic nonlinear aerodynamic correction method, which solves the technical problem that it is difficult to balance calculation accuracy and analysis efficiency in the aerodynamic correction of aircraft in the transonic flight segment. This invention can realize the rapid iteration requirements of overall design and improve the analysis accuracy of engineering aerodynamic methods.
[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0005] A transonic nonlinear aerodynamic correction method includes:
[0006] Divide the surface area of the aircraft into surface elements;
[0007] Based on the surface element division results, the aerodynamic influence coefficient matrix AIC and the downwash velocity matrix W of all surface elements are generated using the dipole lattice method.
[0008] The velocity data of the external flow field of the aircraft were obtained using the steady CFD method;
[0009] Extract the downwash velocity of each surface element from the velocity data of the external flow field of the aircraft;
[0010] The additional angle of attack of each surface element is obtained based on the washing speed of each surface element;
[0011] The effective angle of attack of each surface element is obtained from its additional angle of attack.
[0012] The corrected downwash velocity of each surface element is obtained based on its effective angle of attack. The downwash velocity correction matrix W for all surface elements is then derived from the corrected downwash velocity of each surface element. e ;
[0013] Based on the washing speed matrix W and the washing speed correction matrix W e Obtain the AIC transformation matrix W t ;
[0014] Using the AIC transformation matrix W t The aerodynamic influence coefficient matrix AIC is corrected to obtain the corrected aerodynamic influence coefficient matrix AIC. e ;
[0015] Using the modified aerodynamic influence coefficient matrix AIC e Correct the aerodynamic forces.
[0016] Furthermore, the following relationship exists between the downwash velocity matrix W and the unsteady aerodynamic force Δp of the surface element:
[0017]
[0018] in, For the incoming flow pressure.
[0019] Furthermore, the surface region of the aircraft is divided into surface elements based on the pressure distribution data of the aircraft surface, so that the pressure of each surface element varies at equal intervals in the direction of the incoming flow and the spanwise direction.
[0020] Furthermore, the washing speed of each surface element is the speed at the washing control point of each surface element, and the washing control point of the surface element is the intersection of the cross section in the surface element and the 3 / 4 chord of the surface element.
[0021] Furthermore, the additional angle of attack α of each surface element j It is obtained according to the following formula:
[0022]
[0023] Among them, w j V represents the downwash velocity, and V is the incoming flow velocity used when obtaining the external flow field velocity data of the aircraft using the steady CFD method.
[0024] Furthermore, the effective angle of attack α of each surface element je It is obtained according to the following formula:
[0025] α je =α+α j ;
[0026] Where, α j The additional angle of attack is α, which is the angle of attack of the airflow when the velocity data of the external flow field of the aircraft is obtained using the steady CFD method.
[0027] Furthermore, the corrected washing speed w for each surface element je It is obtained according to the following formula:
[0028] w je =α je *V;
[0029] Where, α je For the effective angle of attack, V is the flow velocity used when obtaining the external flow field velocity data of the aircraft using the steady CFD method.
[0030] Furthermore, the AIC transformation matrix W t It is obtained according to the following formula:
[0031] W t =W*W e -1 .
[0032] Furthermore, the modified aerodynamic influence coefficient matrix AIC e It is obtained according to the following formula:
[0033] AIC e =AIC*W t .
[0034] Furthermore, aeroelastic analysis is performed using the modified aerodynamic force as input.
[0035] Compared with the prior art, the present invention has at least one of the following advantages:
[0036] (1) The present invention uses CFD data to correct the aerodynamic model of the dipole grid method, which makes up for the shortcomings of the engineering aerodynamic method in predicting the surface pressure of the aircraft in the transonic flight segment.
[0037] (2) This invention uses a velocity matrix to correct the aerodynamic characteristics of transonic flight, thereby improving accuracy;
[0038] (3) The present invention can combine the computational accuracy of CFD with the computational efficiency of engineering methods;
[0039] (4) This invention proposes a method for dividing surface elements, which improves the accuracy of the aerodynamic matrix. Attached Figure Description
[0040] Figure 1 This is a block diagram of the transonic nonlinear aerodynamic correction method of the present invention;
[0041] Figure 2 This is a typical aerodynamic grid on the surface of a spacecraft that travels between Earth and space.
[0042] Figure 3 Typical surface flow velocity distribution of a spacecraft that travels between Earth and space;
[0043] Figure 4 This is a schematic diagram of the surface element of the present invention. Detailed Implementation
[0044] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.
[0045] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.
[0046] Space-to-ground launch vehicles differ from traditional axisymmetric rockets in that they typically employ a complex aerodynamic layout with multiple control surfaces and a wing-body combination. This results in high structural elasticity, making them prone to aeroelastic phenomena coupled with aerodynamic forces. Aeroelastic analysis requires aerodynamic forces as input and must balance computational accuracy and efficiency. Engineering aerodynamic models, such as the dipole lattice method, are commonly used for aeroelastic analysis. However, in the transonic flight phase, due to the strongly nonlinear characteristics of aerodynamic forces, engineering methods exhibit significant deviations in prediction accuracy. While CFD methods can accurately describe the nonlinear characteristics of the flow field in transonic flight, their low computational efficiency prevents them from meeting the requirements for rapid iterative overall design.
[0047] This invention proposes a transonic nonlinear aerodynamic correction method. Based on the surface velocity data of the aircraft calculated by CFD, the aerodynamic influence coefficient matrix (AIC) of the dipole grid method is corrected, which takes into account both calculation accuracy and analysis efficiency. It can meet the requirements of rapid iteration of overall design and improve the analysis accuracy of engineering aerodynamic methods.
[0048] This invention discloses a transonic nonlinear aerodynamic correction method for transonic aerodynamic and aeroelastic analysis, comprising the following steps:
[0049] (1) Aerodynamic calculations were performed using the CFD method to obtain surface velocity data;
[0050] (2) Calculate the additional angle of attack and obtain the downwash velocity correction matrix;
[0051] (3) Corrected aerodynamic influence coefficient matrix (AIC);
[0052] (4) Transonic aerodynamic and aeroelastic analyses were performed using the modified AIC matrix.
[0053] Example:
[0054] A transonic nonlinear aerodynamic correction method, based on CFD-calculated aircraft surface velocity data, corrects the dipole lattice aerodynamic model for transonic aerodynamic and aeroelastic analysis. Figure 1 The specific steps of this invention are as follows:
[0055] Step (1): Mesh generation of the aircraft surface
[0056] The surface area of the aircraft is divided into several surface elements. The intersection of the cross section and the 1 / 4 chord line of the segment is marked as the pressure point, and the intersection of the cross section and the 3 / 4 chord line of the segment is marked as the downwash control point. Figure 4 As shown. Figure 2 This is a typical aerodynamic grid on the surface of a spacecraft that travels between Earth and space.
[0057] Step (II): Generate the aerodynamic influence coefficient matrix
[0058] Based on the element division in step one, the aerodynamic influence coefficient matrix AIC is obtained using the dipole lattice method. The unsteady aerodynamic forces and downwash functions of each element can be expressed as a linear relationship, as follows:
[0059]
[0060] Where Δp represents the unsteady aerodynamic force of the surface element. Let AIC be the incoming flow pressure, AIC be the aerodynamic influence coefficient matrix, and W be the downwash velocity matrix at the downwash control point.
[0061] Step (3): CFD calculation of the velocity of the external flow field of the aircraft.
[0062] The velocity data of the external flow field of the aircraft were calculated using the steady CFD method. Figure 3 This is a typical surface velocity distribution of a spacecraft that travels between Earth and space.
[0063] Step (IV) Surface Element Speed Extraction
[0064] Based on the CFD calculation results in step three, the velocity at the wash control point of the j-th element mesh is extracted and defined as the wash velocity w. j .
[0065] Step (5) Calculation of Additional Angle of Attack
[0066] Define the additional angle of attack α at the j-th grid downwash control point. j for:
[0067]
[0068] Where V is the incoming flow velocity used in CFD calculations.
[0069] Step (VI) Calculation of Effective Angle of Attack
[0070] At this point, the effective angle of attack α of the j-th grid is... je It can be represented as:
[0071] α je =α+α j (4)
[0072] Where α represents the incoming flow angle used in CFD calculations.
[0073] Step (7): Correcting the generation of the shuffle matrix
[0074] Based on the effective angle of attack obtained in step five, calculate the corrected downwash velocity w for each surface element. je The definition is as follows:
[0075] w je =α je *V (5)
[0076] The washing speed w at each face element washing control point je Generate the shuffling velocity correction matrix W for all surface elements. e .
[0077] Step (8), AIC Transformation Matrix W t generate
[0078] The washing speed matrix W generated in step two and the washing speed correction matrix W generated in step eight. e calculate:
[0079] W t =W*W e -1 (6)
[0080] Step (IX) Correcting the AIC matrix generation
[0081] The AIC matrix AIC generated in step (2) using the dipole lattice method is right-multiplied by W. t The corrected aerodynamic influence coefficient matrix AIC is obtained. e :
[0082] AIC e =AIC*W t (7)
[0083] Step (10): Complete aerodynamic correction
[0084] Using a positive aerodynamic influence coefficient matrix (AIC) e Aerodynamic and aeroelastic calculations are performed to complete the aerodynamic correction process.
[0085] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.
[0086] The contents not described in detail in this specification are common knowledge to those skilled in the art.
Claims
1. A transonic nonlinear aerodynamic correction method, characterized in that, include: Divide the surface area of the aircraft into surface elements; Based on the surface element partitioning results, the aerodynamic influence coefficient matrix is generated using the dipole lattice method. And the shuffling velocity matrix of all face elements ; The velocity data of the external flow field of the aircraft were obtained using the steady CFD method; Extract the downwash velocity of each surface element from the velocity data of the external flow field of the aircraft; The additional angle of attack of each surface element is obtained based on the washing speed of each surface element; The effective angle of attack of each surface element is obtained from its additional angle of attack. The corrected downwash velocity of each surface element is obtained based on its effective angle of attack. Then, the downwash velocity correction matrix for all surface elements is derived based on the corrected downwash velocity of each surface element. ; According to the washing speed matrix and the correction matrix for the washing speed Obtain the AIC transformation matrix ; Using AIC transformation matrix Influence coefficient matrix on aerodynamic forces After making corrections, the corrected aerodynamic influence coefficient matrix is obtained. ; Using the modified aerodynamic influence coefficient matrix Correct the aerodynamic forces; Downwash velocity matrix Unsteady aerodynamics of surface elements The following conditions must be met: ； in, For the incoming flow pressure; The surface region of the aircraft is divided into elements based on the pressure distribution data of the aircraft surface, so that the pressure of each element varies at equal intervals in the direction of the incoming flow and the spanwise direction. The washing speed of each element is the speed at the washing control point of each element. The washing control point of an element is the intersection of the cross section in the element and the 3 / 4 chord of the element.
2. The transonic nonlinear aerodynamic correction method according to claim 1, characterized in that, Additional angle of attack for each element It is obtained according to the following formula: ； in, For the washing speed, The incoming flow velocity is used when obtaining the velocity data of the external flow field of the aircraft using the steady CFD method.
3. The transonic nonlinear aerodynamic correction method according to claim 1, characterized in that, Effective angle of attack of each element It is obtained according to the following formula: ； in, To add angle of attack, The angle of attack of the flow is used when obtaining the velocity data of the external flow field of the aircraft using the steady CFD method.
4. The transonic nonlinear aerodynamic correction method according to claim 1, characterized in that, Corrected washing speed of each element It is obtained according to the following formula: ； in, For an effective angle of attack, The flow velocity is used when obtaining the velocity data of the external flow field of the aircraft using the steady CFD method.
5. The transonic nonlinear aerodynamic correction method according to claim 1, characterized in that, AIC Transformation Matrix It is obtained according to the following formula: 。 6. The transonic nonlinear aerodynamic correction method according to claim 1, characterized in that, Corrected aerodynamic influence coefficient matrix It is obtained according to the following formula: 。 7. The transonic nonlinear aerodynamic correction method according to claim 1, characterized in that, Aeroelastic analysis was performed using the corrected aerodynamic forces as input.