A method and structure for controlling shock boundary layer interaction by active and passive mixing

Abstract

The application discloses a method and structure for controlling shock wave boundary layer interference by active and passive mixing, and belongs to the technical field of aerodynamics and flow control. The application is directed to an inlet channel with shock wave turbulent boundary layer interaction (SWTBLI), a top circular arc surface of a rotating structural member with a circular cross section is extended into the inlet channel and occupies the main space of an initial separation zone, thereby forming a passive wall bulge; the initial separation zone is an area defined by a zero-speed envelope surface along the main flow direction of the original inlet channel under working conditions; meanwhile, the rotating structural member is driven to rotate around the central axis, and the tangential driving force generated by the top circular arc surface due to rotation is used to actively perform momentum compensation on near-wall fluid. The application can significantly improve the aerodynamic performance of SWTBLI, inhibit large-scale separation and weaken the intensity of turbulent kinetic energy for complex flow conditions such as supersonic inlets.

Description

Technical Field

[0001] This invention belongs to the field of aerodynamics and flow control technology, specifically relating to a method and structure for controlling shock wave boundary layer interference in an aircraft air intake. Background Technology

[0002] During the operation of supersonic and hypersonic vehicles, the Shock Wave / Turbulent Boundary Layer Interaction (SWTBLI) is a common and complex flow phenomenon. Under the influence of a strong adverse pressure gradient, SWTBLI leads to large-scale flow separation within the flow field, forming separation bubbles and low-momentum recirculation regions, which force the mainstream boundary layer to rise significantly and induce separation shock waves.

[0003] This large-scale separation structure not only leads to severe aerodynamic losses, but also has the following negative effects:

[0004] 1. Turbulent kinetic energy amplification: The strong shearing effect within the separated shear layer induces Kelvin-Helmholtz instability, which dominates the turbulent amplification process in the interaction region, leading to increased energy dissipation.

[0005] 2. Slow boundary layer recovery: Large-scale separation leads to a severe momentum deficit in the downstream boundary layer, requiring an extremely long flow direction distance to recover to the equilibrium turbulent boundary layer.

[0006] Traditional single flow control methods have significant limitations in dealing with strong shock wave interference. Traditional passive geometry modifications (such as conventional bulges) are still prone to residual separation at the shock wave incident point or leeward corners; while purely active control often fails to reconstruct large-scale separation regions globally and consumes a lot of energy. Therefore, there is an urgent need for an efficient flow control strategy that can eliminate large-scale separation structures macroscopically, eliminate residual separation locally, and accelerate boundary layer recovery. Summary of the Invention

[0007] The purpose of this invention is to effectively eliminate the large-scale separation structure caused by shock waves in the air intake duct, and to provide a method and structure for actively and passively controlling shock wave boundary layer interference (i.e., interference between shock waves and boundary layers), thereby eliminating residual separation locally and accelerating boundary layer recovery.

[0008] The specific technical solution adopted in this invention is as follows:

[0009] In a first aspect, the present invention provides a method for controlling shock boundary layer interference using a hybrid active and passive approach. For inlet channels exhibiting shock-turbulent boundary layer interaction (SWTBLI), a circular rotating structure with a circular cross-section extends its top arc surface into the inlet channel and occupies the main space of the initial separation zone, thereby forming a passive wall bulge. The initial separation zone is the area defined by the zero-velocity envelope surface along the mainstream direction of the original inlet channel under operating conditions. Simultaneously, by driving the rotating structure to rotate around its central axis, the tangential driving force generated by the rotation of the top arc surface actively compensates for the momentum of the near-wall fluid.

[0010] Secondly, this invention provides an inlet channel structure for actively and passively controlling shock boundary layer interference. The inlet channel contains shock-turbulent boundary layer interaction (SWTBLI). A channel is formed along the cross-section of the channel in the wall region where the shock and turbulent boundary layer interact. A rotating structural member with a circular outer profile is installed in the channel, and the central axis of the rotating structural member is perpendicular to the mainstream direction of the gas in the inlet channel. The top arc surface of the rotating structural member protrudes from the wall region and occupies the main space of the initial separation zone, forming a passive wall bulge. The initial separation zone is the area defined by the zero-velocity envelope surface along the mainstream direction of the original inlet channel under operating conditions. The rotating structural member and the driving mechanism form a transmission cooperation. Under the drive of the driving mechanism, the rotating structural member can rotate around its central axis, and the tangential linear velocity of the top arc surface of the rotating structural member has a velocity component consistent with the mainstream direction, thereby actively compensating for the momentum of the near-wall fluid.

[0011] As a preferred embodiment of the second aspect above, the rotating structural member is in the shape of a cylinder or a disk.

[0012] As a preferred embodiment of the second aspect above, the circular outer contour radius and installation position of the rotating structural component are positioned as follows:

[0013] For the original air intake channel before the channel is opened and the rotating structural component is installed, with the mainstream direction as the positive direction, the region in the original air intake channel where the velocity component of the average flow velocity along the mainstream direction is non-positive is identified as the effective separation zone. Then, based on the outer contour line of the effective separation zone in the longitudinal section of the air intake channel, the separation point, the reattachment point, and the point with the maximum normal height are determined. A unique circle passing through these three points is located, and the radius of this circle is used as the outer contour radius of the rotating structural component. The center of this circle is used as the position of the central axis of the rotating structural component in the longitudinal section of the air intake channel.

[0014] As a preferred embodiment of the second aspect above, the non-positive number is -0.1 to 0 times the free flow velocity component along the mainstream direction.

[0015] As a preferred embodiment of the second aspect above, the non-positive number is -0.008 to -0.002 times the free flow velocity component along the mainstream direction.

[0016] As a preferred embodiment of the second aspect above, the top arc surface of the rotating structure should completely cover the effective separation zone in the direction of the flow channel cross-section.

[0017] As a preferred embodiment of the second aspect above, the rotational speed of the rotating structural component should ensure that the tangential velocity of the top arc surface in the rotating state is 0.1 to 0.5 times the free flow velocity component along the main flow direction.

[0018] As a preferred embodiment of the second aspect above, the driving mechanism is a motor.

[0019] Thirdly, the present invention provides an aircraft having an inlet duct structure for controlling shock boundary layer interference using a hybrid active-passive control method as described in any of the embodiments of the second aspect above.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1) Suppressing large-scale separation: This invention introduces passive wall bulges into the separation zone of the inlet air passage, transforming the highly unstable separation shear layer into an attached flow, thereby cutting off the turbulent kinetic energy generation channel dominated by free shear from a spatial topological perspective.

[0022] 2) Reduced separation shock wave oscillation: The passive wall bulge introduced in this invention effectively shortens the oscillation scale of the separation shock wave, significantly reduces the proportion of low-frequency energy caused by large-scale sweeping in the intermittent region, and effectively improves the unsteady characteristics of the flow field and the dynamic load on the structure.

[0023] 3) Residual separation elimination: This invention actively drives the passive wall bulge in a tangential direction, thereby using the wall adhesion force to inject momentum into the near-wall low-energy fluid in the separation zone, effectively overcoming the local adverse pressure gradient at the shock foot and the leeward side of the bulge, and eliminating the shock incident point separation and corner separation that are difficult to avoid with simple passive control.

[0024] 4) Accelerated flow field recovery: By combining passive wall bulging with active tangential drive, this invention further weakens the near-wall velocity gradient and Reynolds shear stress, accelerates the recovery of the downstream velocity and temperature boundary layer to equilibrium, makes the deceleration and pressurization process more concentrated, and improves the overall pressure recovery efficiency of the supersonic flow channel. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the SWTBLI state in the original intake airflow channel.

[0026] Figure 2A schematic diagram of the inlet air passage structure for controlling shock wave boundary layer interference using a hybrid active and passive control method;

[0027] Figure 3 Schematic diagrams showing different sizes of the characteristic circles in the air intake channel structure;

[0028] Figure 4 A schematic diagram of a supersonic air intake for controlling shock wave boundary layer interference using a hybrid active and passive control method.

[0029] Figure 5 The flow field contour map is for the original inlet air passage.

[0030] Figure 6 This is a schematic diagram of the computational grid for the air intake duct;

[0031] Figure 7 A contour map showing the average flow velocity distribution before and after applying control.

[0032] Figure 8 Normal profiles of average flow velocity at different flow direction positions before and after applying control;

[0033] Figure 9 Distribution of wall pressure along the flow direction before and after applying control;

[0034] Figure 10 Spatial distribution of turbulent kinetic energy in the flow field before and after applying control.

[0035] The figures are labeled as follows: 1. Base plate; 2. Rotating structural component; 3. Drive mechanism; 4. Initial separation zone; 5. Shock generator wedge surface; 6. Incident shock wave; 7. Reflected shock wave; and 8. Expansion wave. Detailed Implementation

[0036] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Technical features in various embodiments of the present invention can be combined accordingly without mutual conflict.

[0037] In the description of this invention, it should be understood that when an element is considered to be "connected" to another element, it can be a direct connection to the other element or an indirect connection, i.e., there is an intermediate element. Conversely, when an element is said to be "directly" connected to another element, there is no intermediate element.

[0038] In the description of this invention, it should be understood that the terms "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0039] This invention systematically analyzes the dynamic mechanism within the shock-turbulent boundary layer interaction (SWTBLI) region of the inlet flow channel from an energy transfer perspective. It shows that the enhancement of turbulent kinetic energy mainly originates from the strong shearing effect within the separation shear layer, while the contribution of mean flow compression (deceleration) is limited to the region near the shock foot. The formation and development of the separation shear layer are key flow structures for enhancing turbulent kinetic energy. From a flow control perspective, if the development of the separation shear layer can be modulated and its momentum transport characteristics improved, the separation scale can be reduced and the overall flow performance optimized. Therefore, this invention constructs a hybrid active-passive control strategy for the separation shear layer: passive control reconstructs the flow structure of the separation region through bulge geometry to achieve directional modulation of the separation bubble; active control applies tangential drive to the bulge surface to compensate for the momentum of the low-momentum fluid, thereby regulating momentum exchange within the shear layer.

[0040] In a preferred embodiment of the present invention, a method for controlling shock boundary layer interference using a hybrid active-passive approach is provided. Specifically, for an inlet duct with SWTBLI (a supersonic inlet duct), the top arc surface of a rotating structural member with a circular cross-section is extended into the inlet duct and occupies the main space of the initial separation zone, thereby forming a passive wall bulge. At the same time, by driving the rotating structural member to rotate around the central axis, the tangential driving force generated by the rotation of the top arc surface is used to actively compensate the momentum of the near-wall fluid close to the arc surface in the separation zone.

[0041] It should be noted that this invention defines the flow direction with the largest velocity component in the inlet channel as the main direction of flow. Therefore, the initial separation zone defined in this invention refers to the area defined by the zero-velocity envelope surface along the main direction of flow in the original inlet channel under operating conditions. The zero-velocity envelope surface is the surface formed by all points in the entire inlet channel where the velocity component along the main direction of flow is 0. The original inlet channel refers to the inlet channel before the introduction of the rotating structural component (including auxiliary structures introduced for installing the rotating structural component, such as slots on the channel wall). The operating conditions of the inlet channel refer to the conditions under which the inlet channel is used in a real-world scenario. The specific operating condition type and parameters need to be determined based on the actual inlet channel being used, and are not limited thereto.

[0042] Additionally, it should be noted that the rotating structural component has a circular cross-section, making it a cylindrical or disc-shaped member. The top arc surface mentioned in this invention is actually a portion of its side surface. The entire rotating structural component can be laid flat and installed below the intake channel with its central axis perpendicular to the center line of the intake channel. A portion of the top of its side surface extends into the intake channel, while the remaining portion remains outside the intake channel. Since the original intake channel is sealed except for the inlet and outlet, slots are generally needed on the channel wall to accommodate the rotating structural component. The specific installation method can be adjusted according to actual conditions.

[0043] Furthermore, the driving rotation direction of the rotating structural component should ensure that the tangential driving force it generates can actively compensate for the momentum of the near-wall fluid close to the arc surface within the separation zone. Since the flow direction of the fluid within the separation zone is opposite to the mainstream direction, the tangential linear velocity at each point on the top arc surface of the rotating structural component should have a velocity component consistent with the mainstream direction in order to actively compensate for the momentum of the near-wall fluid.

[0044] Based on the above method, in another preferred embodiment of the present invention, a hybrid active-passive control inlet airflow channel structure for shock boundary layer interference is further designed. This inlet airflow channel contains shock-turbulent boundary layer interaction (SWTBLI), which needs to be suppressed. For example... Figure 1 The diagram schematically illustrates the state of the inlet airflow duct before any SWTBLI suppression measures are introduced; this is the original inlet airflow duct described above. The Mach number of the free flow (air) within the original inlet airflow duct is shown. Therefore, it belongs to the supersonic inlet. Due to the geometrical abrupt changes on the wall and the initial separation zone 4 generated under the action of a strong adverse pressure gradient, incident shock, separation shock, and expansion waves are generated inside the flow channel. The reflected shock 7 and expansion waves 8 are generated at an angle of... The initial separation region 4 is formed after the incident shock wave 6 hits the initial separation region 4. This initial separation region 4 is the area defined by the zero-velocity envelope surface along the mainstream direction in the original inlet channel under operating conditions. The zero-velocity envelope surface is the surface formed by all points in the entire inlet channel where the velocity component along the mainstream direction is 0 under this operating condition. If the internal space of the inlet channel is discretized into a three-dimensional coordinate system... Therefore, the three-dimensional space of the initial separation region 4 can be defined as follows:

[0045]

[0046] in: Representing coordinates The time-averaged velocity component along the mainstream direction at the location.

[0047]

[0048] Since the longitudinal profile of the inlet air passage is generally uniform, subsequent simulations will be based on... Figure 1 The single longitudinal section shown is used as an example for equivalent explanation. For the longitudinal section of the inlet air passage, this section can be discretized into two-dimensional coordinates. Therefore, the two-dimensional space of the initial separation region 4 can be defined as follows:

[0049]

[0050] in: Representing coordinates The time-averaged velocity component along the mainstream direction at the location. The zero-velocity envelope in two-dimensional space can be defined as:

[0051]

[0052] like Figure 2 As shown, to suppress the separation zone caused by SWTBLI in the original inlet airflow channel, an additional interference suppression structure is introduced into the original inlet airflow channel, including a rotating structure 2 and a drive mechanism 3. Specifically, a through channel is opened in the wall region where the shock wave and turbulent boundary layer interact (i.e., the location corresponding to the separation zone on the bottom plate 1 of the flow channel). The channel needs to be opened along the cross-section of the flow channel, and the length direction of the channel is perpendicular to the centerline of the flow channel. A rotating structure 2 with a circular outer profile is installed at the channel, and the central axis of the rotating structure 2 is perpendicular to the mainstream direction of the gas in the inlet airflow channel. The top arc surface of the rotating structure 2 protrudes from the wall region of the inlet airflow channel, that is, partially extends into the flow channel through the bottom plate 1, and the protruding arc surface needs to occupy the main space of the initial separation zone 4, forming a passive wall bulge. It should be noted that occupying the main space of the initial separation zone 4 means that it needs to occupy most of the space of the initial separation zone 4, but it does not necessarily have to occupy all of the space of the initial separation zone 4. The specific space occupied can be optimized and adjusted according to the actual situation. In theory, occupying a certain amount of space is enough to suppress interference, but the size of the occupied proportion will affect the degree of interference suppression.

[0053] Furthermore, passive wall bulging requires further integration with drive mechanism 3 to introduce active control. See also... Figure 2As shown, the rotating structure 2 and the driving mechanism 3 form a transmission cooperation. Under the drive of the driving mechanism 3, the rotating structure 2 can rotate around the central axis, and the tangential linear velocity of the top arc surface of the rotating structure 2 has a velocity component that is consistent with the mainstream direction in the flow channel, thereby actively compensating for the momentum of the near-wall fluid close to the arc surface in the separation zone.

[0054] It should also be noted that the channel only provides an opening for the rotating structural component 2 to extend into the air intake channel; the fixing and load-bearing of the rotating structural component 2 itself need to be achieved through other external mechanisms. Figure 2 Not shown in the diagram. In practical applications, both the rotating structural component 2 and the drive mechanism 3 can be mounted on a load-bearing fixed frame outside the air intake duct.

[0055] The aforementioned rotating structural component 2 can be cylindrical or disc-shaped, and its interior can be hollow, but its outer wall should be a complete curved surface. Furthermore, Figure 2 The simplified drawing method is used to show the drive mechanism 3. In practical applications, the drive mechanism 3 can be implemented by a motor that can meet the speed requirements of this scenario. The motor can directly drive the rotating structural component 2 through the output shaft or drive the rotating structural component 2 through other transmission mechanisms at a certain speed ratio.

[0056] exist Figure 2 Based on the structure shown, in order to maximally cut off the turbulent kinetic energy generation channel dominated by free shear and achieve the optimal control effect, the present invention also provides a circular outer contour radius of the rotating structural component 2 and its installation position positioned as follows:

[0057] For the original air intake channel before the slot is opened and the rotating structural component 2 is installed (i.e. Figure 1 (As shown in the air intake channel), with the mainstream direction as the positive direction, the region in the original air intake channel where the velocity component of the average flow velocity along the mainstream direction is non-positive is identified as the effective separation zone. Then, based on the outer contour line of the effective separation zone in the longitudinal section of the air intake channel, the separation point, the reattachment point, and the point with the maximum normal height are determined. A unique circle that passes through these three points simultaneously is located. The radius of this circle is used as the outer contour radius of the circular structure 2, and the center of this circle is used as the position of the central axis of the rotating structure 2 in the longitudinal section of the air intake channel.

[0058] It should be noted that the separation point mentioned above refers to the spatial point where the boundary layer flow first detaches from the wall, and the reattachment point refers to the spatial point where the separated flow re-contacts and reattaches to the wall. On a two-dimensional plane, the two are the upstream and downstream intersections of the outer contour line of the separation zone and the wall, respectively. The point with the maximum normal height refers to the spatial point where the vertical distance between the outer contour line of the separation zone and the wall reaches its maximum value.

[0059] It should be noted that the effective separation region in this invention is actually the aforementioned initial separation region 4 or a sub-region of the initial separation region 4. The internal space of the intake air passage is further discretized into a three-dimensional coordinate system. If this is the case, then the three-dimensional space of the effective separation region can be defined as:

[0060]

[0061] in: Representing coordinates The time-averaged velocity component along the mainstream direction at the location. This represents the velocity component of the free flow along the mainstream direction. Coefficient and . This represents the non-positive number used to define the boundary of the separation region.

[0062] Similarly, if defined using the longitudinal profile of the inlet air passage, the profile is discretized into two-dimensional coordinates. After representation, the two-dimensional space of the effective separation region can be defined as:

[0063]

[0064] in: Representing coordinates The time-averaged velocity component along the mainstream direction at the location. This represents the velocity component of the free flow along the mainstream direction. Coefficient and .

[0065] Therefore, it can be seen that the adjustment coefficient can be used. To adjust the proportion of the arc-shaped surface portion of the passive wall bulge occupying the initial separation zone 4. When the coefficient... At that time, the effective separation region belongs to a sub-region of the aforementioned initial separation region 4. However, when the coefficient... At this time, the effective separation region is equivalent to the aforementioned initial separation region 4. The circle located based on the separation point, the reattached point, and the point of maximum normal height is as follows: Figure 3 As shown by the dashed circle in the image, its radius R1 is significantly larger than... Figure 2 Based on coefficients The defined radius R of the circle. However, actual experiments show that near the separation initiation and reattachment positions, as well as in the near-wall bottom layer region, there are often several non-dominant backflow zones with extremely small separation heights. Although these local counterflow structures satisfy the mathematical separation criteria, their scale is small and their duration is limited, making it difficult to reflect the core topological characteristics of the main separation bubble. If they are directly incorporated into the bulge configuration design, it is easy to cause the bulge structure to be too flat, or even introduce non-physical geometric distortions. Therefore, in practical applications, the passive wall bulge does not need to completely occupy the initial separation zone 4; occupying only the main part of it is sufficient to effectively control the separation bubble. Therefore, in this invention, an optimal coefficient can be optimized according to the actual working conditions. This balances the energy loss and separation suppression effect caused by introducing the rotating structural component 2. As a preferred embodiment of the invention, The value ranges from -0.1 to 0, and a further preferred value is -0.008 to -0.002.

[0066] Furthermore, since the actual effective separation zone within the inlet air passage is three-dimensional, it has a certain width in the cross-sectional direction of the passage. The top arc surface of the rotating structure 2 can completely cover the effective separation zone in the cross-sectional direction of the passage, or it can partially cover it. However, from the perspective of optimal control effect, the top arc surface of the rotating structure 2 should cover the effective separation zone as completely as possible in the cross-sectional direction of the passage.

[0067] Furthermore, the rotational speed of the rotating structural component 2 can be optimized according to actual conditions, with the optimal effect of hybrid control shock boundary layer interference suppression as the standard. Theoretically, as long as the rotating structural component 2 rotates, there will be a certain effect of hybrid control shock boundary layer interference suppression. However, as a preferred embodiment of the present invention, the rotational speed of the rotating structural component 2 should ensure that the rotational tangential velocity of the top arc surface in the rotating state is 0.1 to 0.5 times the free flow velocity component along the mainstream direction.

[0068] The above-described active-passive hybrid control shock boundary layer interference inlet structure of the present invention can be applied as a supersonic inlet to aircraft, especially supersonic and hypersonic aircraft. Figure 4As shown, a hybrid active-passive control structure for shock boundary layer interference is introduced into a supersonic inlet. Due to the presence of a shock generator wedge 5, the supersonic inlet generates an incident shock wave. This incident shock wave creates a separation zone (shown by dashed lines) on the base plate 1. The supersonic fluid within the inlet encounters this separation zone, forming a separation shock wave. Therefore, a transverse channel is created on the base plate 1 below the separation zone, and a rotating structural member 2, driven by a drive mechanism 3, is introduced. The rotating structural member 2 is cylindrical, with a length equal to the width of the inlet, and its rotation axis is perpendicular to the main flow direction of the inlet. The arc-shaped portion at the top of the rotating structural member 2 extends into the inlet through the transverse channel, forming a bulge. The arc-shaped surface of the rotating structural member 2 should fit as closely as possible to the edge of the transverse channel, forming a dynamic seal to prevent leakage. The rotating structural member 2 rotates clockwise, thus providing momentum compensation for the near-wall fluid within the separation zone that is close to its arc-shaped surface.

[0069] To better demonstrate the above-mentioned method of controlling shock boundary layer interference using a hybrid active-passive approach, and the specific technical effects of the inlet channel structure for controlling shock boundary layer interference using a hybrid active-passive approach, the interference suppression effect is shown below through specific experiments.

[0070] Example 1

[0071] In this embodiment, in order to select the incident shock wave angle as The effectiveness was verified under strong interference conditions. Furthermore, the criterion for the effective separation region in two-dimensional space was defined as follows:

[0072]

[0073] This threshold criterion can effectively filter out extremely thin reflow layers close to the wall and spurious separations caused by numerical truncation errors during the geometric extraction process, thereby clearly identifying the spatial contour of the core reflow zone.

[0074] The flow field cloud diagram is obtained by simulating the original inlet airflow channel without the introduction of bulges and slots, as shown in the figure. Figure 5 As shown, δ represents the boundary layer thickness at the undisturbed location, y is the normal coordinate of the flow channel, and the x-axis is the horizontal axis. Represents the dimensionless flow direction coordinates in terms of δ. , It is the theoretical incident point of the incident shock wave. Figure 5 The solid white line in the image represents the effective separation region contour extracted based on the above criteria. Based on this contour, three feature points, namely the separation points, can be determined. Adding a dot And the point where the normal height reaches its maximum value within the separation zone. It is worth noting that, due to the significant asymmetry of the separation bubble structure in the flow direction, the location of the maximum separation height point in the flow direction... Generally not located and The geometric midpoint of the point. Then, using the above three feature points as constraints, an arc-shaped bulge passing through these three points is constructed to approximate the geometric contour of the main recirculation zone. This arc-shaped surface can be represented as...

[0075]

[0076] Among them, the center position The radius R is uniquely determined by the three feature points mentioned above. Therefore, when selecting and installing rotating structural components, R is used as the radius of the circular outer contour of the rotating structural component. The central axis of the rotating structural component is positioned within the longitudinal section of the intake air passage.

[0077] from Figure 5 It is evident that this bulge configuration, while maintaining geometric smoothness, can also conform to the asymmetric spatial distribution characteristics of the main separating bubble, providing a reasonable passive geometric basis for the subsequent construction of a hybrid active-passive control strategy.

[0078] Once the radius and center position of the circular outer contour of the rotating structural component are determined, numerical simulation is performed using the computational fluid dynamics software OpenCFD. Figure 6 This is the computational mesh for the constructed inlet channel. To avoid the potential adverse effects of curved walls on the accuracy of numerical discretization, this embodiment solves the governing equations in a general curvilinear coordinate system. During mesh generation, local orthogonalization is performed on the region near the bulge to ensure that the velocity and thermodynamic gradients in the near-wall region can be sufficiently distinguished and to minimize the numerical errors introduced by geometric mapping. Figure 6 The magnified view within the red box clearly shows the mesh orthogonality near the wall and the mesh refinement strategy within the boundary layer.

[0079] Based on the above grid and numerical settings, this embodiment considers four sets of examples for comparative analysis:

[0080] The first group consists of examples without control baselines ( ): That is, no interference suppression structure (no slotted or rotating structural components) is introduced into the original air intake channel;

[0081] The second group consists of passive control examples that only introduce passive wall bulges. ): That is, a rotating structural component is introduced into the original air intake channel through a slot in the bottom plate below the flow splitting zone. The radius and center position of the rotating structural component are determined according to... Figure 5 The three feature points obtained are used to determine and locate the components; the rotating structural components remain fixed and do not rotate.

[0082] The third group consists of examples of active-passive hybrid control with low-speed rotary drive, which are further superimposed on the passive bulge. Based on the rotating structural components introduced in the second group, the rotation of the rotating structural components is further controlled, and the tangential rotational velocity of the side wall arc surface is equal to the free flow velocity. 0.14 times;

[0083] The fourth group consists of a hybrid active-passive control example that further superimposes low-speed rotary drive on the passive bulge. Based on the rotating structural components introduced in the second group, the rotation of the rotating structural components is further controlled, and the tangential rotational velocity of the side wall arc surface is equal to the free flow velocity. 0.28 times. Therefore, when At that time, the ratio of the effective separation zone length to the bulge radius was 0.49. The tangential rotational velocity of the bulge surface... The characteristic velocity (corresponding to the rotational angular velocity is) Using the radius R of the arc as the characteristic length, the rotational Reynolds number corresponding to the control input can be defined as:

[0084]

[0085] In the formula: The fluid density inside the intake manifold. This refers to the viscosity of the fluid inside the air intake.

[0086] Therefore, the above control example and Their respective rotational Reynolds numbers The values ​​are 130,000 and 260,000.

[0087] To ensure the comparability of flow field responses under different control methods, all controlled cases used the same computational domain size, inflow conditions, numerical format, and time progression strategy, differing only in the magnitude of the driving velocity at the bulge wall. The final calculation results for the four cases are shown below:

[0088] Figure 7 The diagram shows the mean flow velocity distribution contours of the flow field before and after applying control for four examples (negative velocities indicate flow separation). It can be seen that before adding the bulge control (Base), a large-scale separation region exists in the flow field (enclosed by the black solid line); after adding the passive bulge (…),… The separation range is significantly reduced, with only a small separation zone existing at the leading edge and top of the bulge; after adding active control to the bulge ( , The obvious disappearance of the separation zone at the top indicates that the current passive bulge combined with active rotation drive control can significantly suppress flow separation and reduce the separation zone range.

[0089] Figure 8 The figure shows the average flow velocity normal profiles at different flow directions in four examples before and after control was applied. For visual clarity, the different flow directions are shown in the figure. The average flow velocity of the profile in the horizontal direction By integer offset The translation is performed. The main result is whether the average flow velocity can quickly recover to 1 in the normal direction; a fuller profile indicates a better effect. It can be seen that upstream... At the point where the flow field is unaffected by the shock wave, all profiles completely overlap; however, after being affected by the shock wave ( All lines), the velocity profile is fuller after the introduction of bump control ( The red line The yellow line is... (The blue line indicates that the control accelerated the boundary layer's recovery to an equilibrium state; compared to pure bulge control) After adding active control ( The downstream boundary layer recovers faster (the velocity profile is fuller), and the active drive intensity increases with the increase of the drive speed. The driving strength is higher than The stronger the driving force, the faster the downstream boundary layer recovers (the fuller the profile of the blue line).

[0090] Figure 9 The average wall pressure of the flow field before and after applying control is shown in four examples. The distribution along the flow direction is shown, with the black dotted line indicating a better effect as the pressure reaches approximately 3.25 more quickly. It can be seen that before control (Base, solid black line), downstream... The downstream pressure was far from recovered, but after adding bulge control, the downstream pressure recovered faster (approaching the black dotted line more quickly); further active drive was added on top of the bulge ( Pressure recovery is relatively pure bulge ( It is faster, and pressure recovery is further accelerated as the intensity of active control increases.

[0091] Figure 10 The spatial distribution of turbulent kinetic energy in the flow field before and after control is shown for four examples. A smaller K indicates lower turbulent kinetic energy and better control performance. It can be seen that before control (Base), the turbulent kinetic energy value is larger and has a wider range; after adding bulge control (… The value of turbulent kinetic energy is significantly reduced, and its spatial distribution range is smaller; after adding active drive control ( , The value of turbulent kinetic energy decreases further, and the value of downstream turbulent kinetic energy decreases even more with the increase of active control intensity. The turbulent kinetic energy value ratio Smaller).

[0092] In summary, this invention introduces a rotating structural component as a passive bulge into the inlet airflow channel. By geometrically filling and solidifying the large-scale separation zone, it transforms the highly unstable separation shear layer into attached flow, eliminating the large-scale separation structure at its source. Furthermore, active tangential driving further enhances near-wall momentum transport, suppresses local separation, and accelerates the recovery of the downstream velocity and temperature boundary layer to equilibrium, while also promoting pressure recovery after the interaction. From the perspective of turbulent statistical characteristics, this control strategy significantly alters the turbulent structure within the separation zone. The passive bulge weakens shear-dominated turbulence generation in the interaction zone by eliminating the separation shear layer; furthermore, active control further suppresses turbulent kinetic energy by modulating near-wall shear.

[0093] The embodiments described above are merely some preferred implementations of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A method for controlling shock wave boundary layer interference using a hybrid active-passive control approach, characterized in that, For inlet channels with shock wave-turbulent boundary layer interaction, the top arc surface of a rotating structural component with a circular cross-section extends into the inlet channel and occupies the main space of the initial separation zone, thereby forming a passive wall bulge. The initial separation zone is the area defined by the zero-velocity envelope surface along the mainstream direction of the original inlet channel under working conditions. At the same time, by driving the rotating structural component to rotate around the central axis, the tangential driving force generated by the rotation of the top arc surface is used to actively compensate the momentum of the near-wall fluid.

2. An inlet air passage structure for hybrid active and passive control of shock wave boundary layer interference, wherein shock wave-turbulent boundary layer interaction exists in the inlet air passage, characterized in that, The inlet airflow channel has a channel along its cross-section in the wall region where the shock wave and turbulent boundary layer interact. A rotating structural component with a circular outer profile is installed in the channel, and the central axis of the rotating structural component is perpendicular to the mainstream direction of the gas in the inlet airflow channel. The top arc surface of the rotating structural component protrudes from the wall region and occupies the main space of the initial separation zone, forming a passive wall bulge. The initial separation zone is the area defined by the zero-velocity envelope surface along the mainstream direction of the original inlet airflow channel under working conditions. The rotating structural component and the drive mechanism form a transmission cooperation. Under the drive of the drive mechanism, the rotating structural component can rotate around its central axis, and the tangential linear velocity of the top arc surface of the rotating structural component has a velocity component consistent with the mainstream direction, thereby actively compensating for the momentum of the near-wall fluid.

3. The intake channel structure for hybrid active-passive control of shock wave boundary layer interference as described in claim 2, characterized in that, The rotating structural component is in the shape of a cylinder or a disk.

4. The intake channel structure for hybrid active-passive control of shock wave boundary layer interference as described in claim 2, characterized in that, The radius of the circular outer contour of the rotating structural component and its installation position are determined as follows: For the original air intake channel before the channel is opened and the rotating structural component is installed, with the mainstream direction as the positive direction, the region in the original air intake channel where the velocity component of the average flow velocity along the mainstream direction is non-positive is identified as the effective separation zone. Then, based on the outer contour line of the effective separation zone in the longitudinal section of the air intake channel, the separation point, the reattachment point, and the point with the maximum normal height are determined. A unique circle passing through these three points is located, and the radius of this circle is used as the outer contour radius of the rotating structural component. The center of this circle is used as the position of the central axis of the rotating structural component in the longitudinal section of the air intake channel.

5. The intake channel structure for hybrid active-passive control of shock wave boundary layer interference as described in claim 4, characterized in that, The non-positive number is -0.1 to 0 times the free flow velocity component along the mainstream direction.

6. The intake channel structure for hybrid active-passive control of shock wave boundary layer interference as described in claim 5, characterized in that, The non-positive number is -0.008 to -0.002 times the free flow velocity component along the mainstream direction.

7. The intake channel structure for hybrid active-passive control of shock wave boundary layer interference as described in claim 5, characterized in that, The top arc surface of the rotating structural component should completely cover the effective separation zone in the direction of the flow channel cross-section.

8. The intake channel structure for hybrid active-passive control of shock wave boundary layer interference as described in claim 2, characterized in that, The rotational speed of the rotating structural component should ensure that the tangential velocity of the top arc surface in the rotating state is 0.1 to 0.5 times the free flow velocity component along the main flow direction.

9. The intake channel structure for hybrid active-passive control of shock wave boundary layer interference as described in claim 2, characterized in that, The driving mechanism is a motor.

10. An aircraft, characterized in that, An inlet air passage structure with active-passive hybrid control of shock boundary layer interference as described in any one of claims 2 to 9.

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