CN117669056B - Pneumatic structure for inhibiting wing flutter based on bionic concave-convex front edge and optimization method - Google Patents
Pneumatic structure for inhibiting wing flutter based on bionic concave-convex front edge and optimization method Download PDFInfo
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Abstract
The invention discloses a pneumatic structure for inhibiting wing flutter based on a bionic concave-convex front edge and an optimization method, which relate to the technical field of aviation and comprise a beam-shell type structure, wherein the beam-shell type structure comprises a straight beam, a prototype wing shell and a bionic concave-convex front edge wing shell, the straight beam horizontally passes through the bottoms of the prototype wing shell and the bionic concave-convex front edge wing shell, the prototype wing shell is arranged on one side of the bionic concave-convex front edge wing shell, a through hole is formed in one side, far away from the prototype wing shell, of the straight beam, a first wing rib and a second wing rib are embedded in the straight beam, the first wing rib and the second wing rib are arranged in parallel perpendicular to the straight beam, the first wing rib is arranged on one side, close to the through hole, of the prototype wing shell, and is connected with the prototype wing shell, and the second wing rib is connected with the bionic concave-convex front edge wing shell. By adopting the pneumatic structure, the flow direction vortex structure is passively generated by the fluid passing through the bionic concave-convex front edge structure, so that the flow separation can be effectively controlled, the critical flutter speed of the aircraft is improved, the occurrence of flutter is reduced, and the aircraft has better pneumatic performance.
Description
Technical Field
The invention relates to the technical field of aviation, in particular to a pneumatic structure for inhibiting wing flutter based on a bionic concave-convex leading edge and an optimization method.
Background
In order to navigate in thin high altitude for a long time, a super high altitude solar unmanned aerial vehicle can be provided with a wing with a large aspect ratio to acquire enough lift force and a solar panel surface area; the wind turbine also increases aerodynamic efficiency and increases wind energy capture efficiency per unit of the wind turbine by increasing the aspect ratio of the blades to reduce induced drag caused by downwash at the tip location. The wings of such elongated structures may exhibit significant structural flexibility characteristics. In addition, in order to reduce weight, the proportion of the composite material is higher, the wing structure is lightened in design, and the flexibility characteristic of the wing is further enhanced. The flexible elastic airfoil structure has a low natural frequency which can be as low as 0.6Hz, once encountering low-frequency gusts, the airfoil structure is extremely easy to resonate with external turbulence, the abrupt change of the airfoil load is caused, and the safety and the maneuverability of the aircraft structure are seriously threatened.
At present, two main modes of controlling wing flutter are respectively passive changing of wing structure and active control of wing flow field: 1) The mass distribution of the wing is changed through a mechanical structure, so that the local rigidity of the wing is improved, the critical flutter speed of the aircraft is improved, and the condition of flutter is more severe; 2) When the wing flutters, the surface of the wing always has a periodical separation and reattachment flow structure, and the air blowing active control device can effectively reduce the flow separation area on the surface of the wing, so that the periodical separation and reattachment process can not occur any more, and the flutter phenomenon is restrained.
The existing device for changing the mass distribution of the wing through a mechanical structure is quite heavy and complex, and the response speed is very slow or the expected mass distribution situation cannot be realized completely due to insufficient force for changing the mass in the use process, so that the device for changing the mass distribution is inconvenient to use and poor in stability, and the weight of an aircraft is increased by the method, and the energy utilization and economic benefits are reduced.
The existing active wing blowing device controls flow separation of the wing surface by transmitting energy to a flow field on the wing surface in a blowing mode, however, a control command and a blowing exciter respond in a time lag mode, a period of time is needed after blowing to enable the wing surface to flow and reattach, and meanwhile, the limited energy and the limited action range provided by blowing lead to limited capability of controlling the flow separation. Without a very effective method of predicting flutter, the aircraft can only turn on the active blowing device after the occurrence of flutter, at which time structural damage may be caused by long convergence time or by limited control capability such that severe vibrations caused by the flutter are not timely and effectively relieved.
Disclosure of Invention
The invention aims to provide a pneumatic structure for inhibiting wing flutter based on a bionic concave-convex front edge and an optimization method, wherein fluid passively flows to a vortex structure through the bionic concave-convex front edge structure, so that flow separation can be effectively controlled, the critical flutter speed of an aircraft is improved, and the occurrence frequency of flutter is reduced. Meanwhile, the bionic concave-convex leading edge structure is adopted, so that the lift-drag ratio of the wing can be improved, and the static stall attack angle can be increased, and the wing has better aerodynamic performance. The method for passively controlling the wing surface flow field is convenient and simple to realize without considering an active control algorithm and additional sensors and exciters, and can achieve the purpose of restraining flutter only by changing the aerodynamic shape near the wing tip of the wing.
In order to achieve the above purpose, the invention provides a pneumatic structure for restraining wing flutter based on a bionic concave-convex front edge and an optimization method, which comprises a beam-shell structure, wherein the beam-shell structure comprises a straight beam, a prototype wing shell and a bionic concave-convex front edge wing shell, the straight beam horizontally penetrates through the prototype wing shell and the lower part of the bionic concave-convex front edge wing shell, the prototype wing shell is arranged on one side of the bionic concave-convex front edge wing shell, a through hole is formed in one side of the straight beam far away from the prototype wing shell, a first wing rib and a second wing rib are embedded in the straight beam, the first wing rib and the second wing rib are arranged in parallel perpendicular to Ping Zhiliang, the first wing rib is arranged on one side close to the through hole and is connected with the prototype wing shell, and the second wing rib is connected with the bionic concave-convex front edge wing shell.
Preferably, the material of the prototype wing shell and the material of the bionic concave-convex front edge wing shell are both ABS resin, the prototype wing shell comprises a prototype front edge and a first rear shell, a first mounting groove is formed in the first rear shell, the bionic concave-convex front edge wing shell comprises a bionic concave-convex front edge and a second rear shell, and a second mounting groove is formed in the second rear shell.
Preferably, the front edge of the prototype is fixed with the first rear shell through fixing screws, the number of the first rear shells is two, and the first rear shells are connected with the first ribs through the first mounting grooves; the bionic concave-convex front edge is fixed with the second rear shells through fixing screws, the number of the second rear shells is two, and the second rear shells are connected with the second wing ribs through the second mounting grooves.
Preferably, the bionic concave-convex front edge comprises two design parameters, the wavelength is along the length direction, the amplitude is along the height direction, and the bionic concave-convex front edge adopts a constant wavelength variable amplitude setting.
Preferably, wherein the wavelength is fixed at 10mm, the amplitude is 6 x sin (pi/170 x) in length, where x represents the distance to the end.
Preferably, the number of the through holes is five, and the five through holes are respectively arranged at four vertexes and center points of one end of the rectangular straight beam.
An optimization method for inhibiting wing flutter based on bionic concave-convex leading edge comprises the following steps:
S1: the shape of the bionic concave-convex front edge refers to the bulge of the front edge of the whale pectoral fin of the seat head, and the size parameter of the concave-convex front edge is obtained by combining the design of the wing profile;
S2: the inhibition effect of the concave-convex front edge of the size parameter on the flutter of the wing with the large aspect ratio is measured through a wind tunnel experiment;
S3: and optimizing the size parameter of the concave-convex front edge for a plurality of times according to the test result, and finally determining the optimal concave-convex front edge size parameter for inhibiting flutter.
Preferably, the optimum design of the concave-convex front edge size comprises 4 parameters, and the amplitude of the concave-convex front edge on the wing at the distance x from the wing root is expressed as:
Wherein A (x) is the concave-convex front edge amplitude, x is the distance between the wing and the wing heel, x 0 is the distance between the center position and the wing root, A 0 is the maximum concave-convex amplitude, lambda is the wavelength, and L is the total width of the concave-convex front edge.
Preferably, after the amplitude of the concave-convex front edge is determined, the front 1/4 part of the wing airfoil is used as a contour and used as a guide line for lofting to form a smooth bionic concave-convex front edge appearance, the bionic concave-convex front edge is combined with the rear 3/4 part of the wing airfoil, and mounting holes are cut out for being embedded into a straight beam to form a complete integral bionic concave-convex front edge wing.
Preferably, in the wind tunnel experiment described in step S2, whether flutter occurs is determined by measuring deformation and vibration of the wing and flow fields around the wing;
Periodic leading edge vortex and trailing edge vortex shedding occur on the surface of the wing, so that large-range flow separation is caused, the aerodynamic force of the wing is changed in a quasi-periodic manner, the structure of the wing is vibrated in a corresponding periodic large scale, and stall flutter occurs;
The deformation and vibration of the wing are measured through a DIC (digital image correlation); the flow field around the wing is measured by particle image velocimetry PIV.
Therefore, the pneumatic structure and the optimization method for inhibiting wing flutter based on the bionic concave-convex leading edge have the following beneficial effects:
(1) The flow direction vortex structure is passively generated by the fluid passing through the bionic concave-convex front edge structure, and the flow separation can be effectively controlled, so that the critical flutter speed of the aircraft is improved, and the occurrence frequency of flutter is reduced.
(2) The bionic concave-convex leading edge structure is adopted, so that the lift-drag ratio of the wing can be improved, the static stall attack angle can be increased, and the wing has better aerodynamic performance.
(3) According to the method for passively controlling the wing surface flow field, an active control algorithm, an additional sensor and an exciter are not required to be considered, the structure is simple, convenient and easy to achieve, the purpose of inhibiting the flutter can be achieved by only changing the aerodynamic shape near the wing tip of the wing, the occurrence of the flutter can be inhibited once the wing is installed, and the aerodynamic performance of the wing is improved.
The technical scheme of the invention is further described in detail through the drawings and the embodiments.
Drawings
FIG. 1 is a schematic diagram of the overall structure of a pneumatic structure for inhibiting wing flutter based on a bionic concave-convex leading edge;
FIG. 2 is a schematic diagram of a straight beam structure of a pneumatic structure for inhibiting wing flutter based on a bionic concave-convex leading edge;
fig. 3 is a schematic diagram of a prototype wing shell structure of a pneumatic structure for suppressing wing flutter based on a bionic concave-convex leading edge.
FIG. 4 is a schematic diagram of a bionic concave-convex leading edge shell structure of a pneumatic structure for inhibiting wing flutter based on the bionic concave-convex leading edge;
FIG. 5 is a schematic diagram of a bionic concave-convex leading edge structure based on a pneumatic structure for suppressing wing flutter by the bionic concave-convex leading edge;
FIG. 6 is a schematic diagram of a bionic concave-convex leading edge control mechanism based on a pneumatic structure for suppressing wing flutter by the bionic concave-convex leading edge;
FIG. 7 is a diagram of the average result of a flutter suppression flow field based on a bionic concave-convex leading edge flutter suppression aerodynamic structure of the invention;
FIG. 8 is a flutter suppression result diagram of a pneumatic structure for suppressing wing flutter based on a bionic concave-convex leading edge;
FIG. 9 is a schematic diagram of an optimization parameter profile of an optimization method for suppressing wing flutter based on a bionic concave-convex leading edge;
FIG. 10 is an assembly view of a bionic concave-convex leading edge wing based on a method of optimizing the suppression of wing flutter by the bionic concave-convex leading edge of the present invention;
Reference numerals
1. A through hole; 2. a straight beam; 3. prototype wing shells; 4. a first rib; 41. a second rib; 5. bionic concave-convex front edge wing shells; 6. prototype leading edges; 7. a first rear case; 8, fixing a screw; 9. a first mounting groove; 10. bionic concave-convex front edge; 11. a second rear case; 12. and a second mounting groove.
Detailed Description
The technical scheme of the invention is further described below through the attached drawings and the embodiments.
Unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The terms "first," "second," and the like, as used herein, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", etc. are used merely to indicate relative positional relationships, which may also be changed when the absolute position of the object to be described is changed.
As shown in fig. 1, the structure comprises a beam-shell structure, wherein the beam-shell structure comprises a straight beam 2, a prototype wing shell 3 and a bionic concave-convex front edge wing shell 5, the straight beam 2 horizontally penetrates through the lower parts of the prototype wing shell 3 and the bionic concave-convex front edge wing shell 5, the prototype wing shell 3 is arranged on one side of the bionic concave-convex front edge wing shell 5, through holes 1 are formed in one side, far away from the prototype wing shell 3, of the straight beam 2, the five through holes 1 are respectively formed in four vertexes and center points of one end of the rectangular structure of the straight beam 2, and the through holes 1 are connected with a fixing device such as a machine body to enable the machine body to be a cantilever wing. The structure of the straight beam 2 is shown in fig. 2, 45 steel is adopted to ensure the strength of the whole structure, the straight beam 2 is embedded with a first wing rib 4 and a second wing rib 41, the first wing rib 4 and the second wing rib 41 are arranged in parallel perpendicular to the straight beam 2, the first wing rib 4 is arranged on one side close to the through hole 1 and is connected with the prototype wing shell 3, and the second wing rib 41 is connected with the bionic concave-convex front edge wing shell 5.
The material of the prototype wing shell 3 and the bionic concave-convex front edge wing shell 5 are both made of ABS resin, the prototype wing shell 3 comprises a prototype front edge 6 and a first rear shell 7, the structure of the prototype wing shell is shown in fig. 3, a first mounting groove 9 is formed in the first rear shell 7, the bionic concave-convex front edge wing shell 5 comprises a bionic concave-convex front edge 10 and a second rear shell 11, and a second mounting groove 12 is formed in the second rear shell 11.
The prototype front edge 6 is fixed with the first rear shell 7 through fixing screws 8, the number of the first rear shells 7 is two, and the first rear shell 7 is connected with the first wing rib 4 through a first mounting groove 9; the bionic concave-convex front edge 10 and the second rear shell 11 are fixed through the fixing screws 8, the number of the second rear shells 11 is two, and the second rear shells 11 are connected with the second wing ribs 41 through the second mounting grooves 12.
The bionic concave-convex front edge 10 comprises two design parameters, the structure of the bionic concave-convex front edge is shown in fig. 4, the wavelength is taken as a wavelength along the length direction, the amplitude is taken as an amplitude along the height direction, and the bionic concave-convex front edge 10 adopts a constant wavelength and variable amplitude setting. As shown in fig. 5, where the wavelength is fixed at 10mm, the amplitude is 6 x sin (pi/170 x) along the length, where x represents the distance to the end.
As shown in FIG. 6, the fluid passing over the raised structures of the peaks passively create a set of mutually rotating flow vortices that inhibit flow separation of the airfoils. The flow control result is shown in fig. 7, when the flutter critical wind speed is reached, the airfoil surface can generate periodic leading edge vortex and trailing edge vortex to drop, so that large-range flow separation is caused, the aerodynamic force of the airfoil is caused to generate quasi-periodic change, and the structure of the airfoil is correspondingly periodically deformed in a large scale, namely, the airfoil stall flutter is generated. After the aerodynamic profile of the wing is optimized by adopting the bionic concave-convex front edge, the flow vortex generated by the bionic concave-convex front edge inhibits the flow separation of the wing surface, so that the wing surface presents an attached flow state, and no periodical vortex generation and falling-off processes occur, so that the aerodynamic force of the wing does not obviously fluctuate, the structure of the wing also does not obviously deform, and the occurrence of wing flutter is inhibited. The wing with the bionic concave-convex front edge aerodynamic shape can enable the wing surface to be in an attached flow state under all working conditions, so that fluctuation of aerodynamic load and vibration of a wing structure are reduced, the control result is that, for example, as shown in fig. 8, the original large-aspect-ratio wing is obviously deformed before the flutter critical wind speed is reached, the flutter is generated when the original large-aspect-ratio wing reaches the flutter critical wind speed, the vibration amplitude is continuously increased along with further rising of the wind speed, and after the aerodynamic shape of the wing is optimized by adopting the bionic concave-convex front edge, even if the incoming wind speed is far higher than the flutter critical wind speed, the obvious deformation is not generated, and the occurrence of the flutter is restrained.
Flutter: when the flexible blades of aircrafts, wind driven generators and the like are subjected to aerodynamic force, elastic force and inertial force coupling action, serious self-excited vibration phenomenon occurs.
High aspect ratio wing: the aspect ratio of a wing is the ratio of the span length to the chord length of the wing, and a large aspect ratio wing is longer and narrower than a small aspect ratio wing. One component of aircraft drag is known as induced drag, which is inversely proportional to the aspect ratio, and therefore large aspect ratio wings can have a greater lift-to-drag ratio.
An optimization method for inhibiting wing flutter based on bionic concave-convex leading edge comprises the following steps:
S1: the shape of the bionic concave-convex front edge refers to the bulge of the front edge of the whale pectoral fin of the seat head, and the size parameter of the concave-convex front edge is obtained by combining the design of the wing profile;
S2: the inhibition effect of the concave-convex front edge of the size parameter on the flutter of the wing with the large aspect ratio is measured through a wind tunnel experiment;
S3: and optimizing the size parameter of the concave-convex front edge for a plurality of times according to the test result, and finally determining the optimal concave-convex front edge size parameter for inhibiting flutter.
As shown in fig. 9, the optimum design of the concave-convex front edge size includes 4 parameters, and the amplitude of the concave-convex front edge on the wing at the distance x from the wing root is expressed as:
Wherein A (x) is the concave-convex front edge amplitude, x is the distance between the wing and the wing heel, x 0 is the distance between the center position and the wing root, A 0 is the maximum concave-convex amplitude, lambda is the wavelength, and L is the total width of the concave-convex front edge.
As shown in fig. 10, after the amplitude of the concave-convex front edge is determined, the front 1/4 part of the wing airfoil is used as a contour and used as a guide line for lofting to form a smooth bionic concave-convex front edge, the bionic concave-convex front edge is combined with the rear 3/4 part of the wing airfoil, and mounting holes are cut out for being embedded into a straight beam to form a complete integral bionic concave-convex front edge wing.
When fluid passes through the concave-convex front edge outline structure, a group of reverse rotating flow direction vortex is passively generated at the convex position, and the flow direction vortex can inhibit flow separation of the wing; the uneven front edge with unequal amplitude can generate a flow direction vortex array with the vortex strength changing along the wing spanwise direction, and can inhibit the flow separation of the wing in a larger attack angle range.
In the wind tunnel experiment of the step S2, whether flutter occurs or not is judged by measuring deformation and vibration of the wing and flow fields around the wing;
Periodic leading edge vortex and trailing edge vortex shedding occur on the surface of the wing, so that large-range flow separation is caused, the aerodynamic force of the wing is changed in a quasi-periodic manner, the structure of the wing is vibrated in a corresponding periodic large scale, and stall flutter occurs;
The deformation and vibration of the wing are measured through a DIC (digital image correlation); the flow field around the wing is measured by particle image velocimetry PIV.
Example 1
Experimental test method for inhibiting flutter of bionic concave-convex front edge
A) The wing root of the wing with the large aspect ratio is fixed on a bracket of the wind tunnel for experimental test, and whether flutter occurs is judged mainly by measuring deformation and vibration of the wing and a flow field around the wing. When periodic leading edge vortex and trailing edge vortex shedding occur on the surface of the wing, large-range flow separation is caused, so that quasi-periodic change of aerodynamic force of the wing and corresponding periodic large-scale vibration of the structure of the wing occur, and stall flutter occurs at the moment.
B) Deformation and vibration of the wing were measured by Digital Image Correlation (DIC); the flow field around the wing is measured by particle image velocimetry (PARTICLE IMAGE velocimetry, PIV).
C) The experiment firstly gives the attack angle of the wing, then increases the wind speed step by step, and at each appointed wind speed, the deformation and vibration of the current wing and the surrounding flow field are measured.
As shown in table 1, the average amplitude of the wing tip torsional vibration of the prototype wing and the optimized bionic concave-convex leading edge wing at an angle of attack of 18 ° is given. The wing tip torsional vibration amplitude of the prototype wing is obviously increased at the wind speed of 20.5m/s, which indicates that the wing at the moment has entered a large-amplitude flutter state. The vibration amplitude continues to increase with wind speed.
E) The optimized bionic concave-convex leading edge wing does not generate large-amplitude torsional vibration at all tested wind speeds, which indicates that the wing does not generate flutter, namely the front of the bionic concave-convex inhibits the wing flutter.
F) The flow diagram and the vorticity distribution diagram of the flow field of the prototype wing and the bionic concave-convex leading edge wing at the wind speed of 20.5m/s at the angle of attack of 18 degrees are shown in figure 4. The flow field sampling position is 0.85 wing length section from the wing root. At this time, the prototype wing has flutter, and severe deformation of the section of the wing can be observed. Meanwhile, the generated leading edge vortex and trailing edge vortex are in shedding phenomenon at the back of the section of the wing, periodic large-scale flow separation occurs at the leading edge of the wing, so that aerodynamic force of the wing is changed in a quasi-periodic manner, corresponding periodic large-scale deformation occurs in the structure of the wing, and wing stall flutter occurs.
After the aerodynamic profile of the wing is optimized by adopting the bionic concave-convex front edge, the flow vortex generated by the bionic concave-convex front edge inhibits the flow separation of the wing surface, so that the wing surface presents an attached flow state, and the periodical vortex generation and falling-off processes are not generated any more, so that the aerodynamic force of the wing does not obviously fluctuate, the structure of the wing also does not obviously deform, and the occurrence of wing flutter is inhibited.
Comparative example
When the surface of the prototype wing reaches the flutter critical wind speed, periodic leading edge vortex and trailing edge vortex drop to cause large-range flow separation, so that aerodynamic force of the wing is subjected to quasi-periodic change, the structure of the wing is subjected to corresponding periodic large-scale vibration, and wing stall flutter is generated.
After the aerodynamic profile of the wing is optimized by the bionic concave-convex front edge, the flow vortex generated by the bionic concave-convex front edge inhibits the flow separation of the wing surface, so that the wing surface presents an attached flow state, and no periodical vortex generation and falling-off processes occur, so that the aerodynamic force of the wing does not obviously fluctuate, the structure of the wing also does not obviously deform, and the occurrence of wing flutter is inhibited.
In conclusion, the wing with the optimized aerodynamic profile of the bionic concave-convex front edge can enable the wing surface to be in an attached flow state under a larger attack angle, so that fluctuation of aerodynamic load and vibration of a wing structure are reduced.
Therefore, the pneumatic structure and the optimization method for inhibiting wing flutter based on the bionic concave-convex front edge are adopted, fluid passively flows to the vortex structure through the bionic concave-convex front edge structure, and flow separation can be effectively controlled, so that the critical flutter speed of an aircraft is improved, and the occurrence frequency of flutter is reduced. Meanwhile, the bionic concave-convex leading edge structure is adopted, so that the lift-drag ratio of the wing can be improved, and the static stall attack angle can be increased, and the wing has better aerodynamic performance. The method for passively controlling the wing surface flow field is convenient and simple to realize without considering an active control algorithm and additional sensors and exciters, and can achieve the purpose of restraining flutter only by changing the aerodynamic shape near the wing tip of the wing.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention and not for limiting it, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that: the technical scheme of the invention can be modified or replaced by the same, and the modified technical scheme cannot deviate from the spirit and scope of the technical scheme of the invention.
Claims (5)
1. The utility model provides a pneumatic structure based on bionical unsmooth leading edge restraines wing flutter which characterized in that: the bionic concave-convex front edge wing structure comprises a beam-shell type structure, wherein the beam-shell type structure comprises a straight beam, a prototype wing shell and a bionic concave-convex front edge wing shell, the straight beam horizontally penetrates through the lower parts of the prototype wing shell and the bionic concave-convex front edge wing shell, the prototype wing shell is arranged on one side of the bionic concave-convex front edge wing shell, a through hole is formed in one side, far away from the prototype wing shell, of the straight beam, a first wing rib and a second wing rib are embedded in the straight beam, the first wing rib and the second wing rib are perpendicular to Ping Zhiliang and are arranged in parallel, the first wing rib is arranged on one side, close to the through hole, and is connected with the prototype wing shell, and the second wing rib is connected with the bionic concave-convex front edge wing shell;
The material of the prototype wing shell and the material of the bionic concave-convex front edge wing shell are both ABS resin, the prototype wing shell comprises a prototype front edge and a first rear shell, a first mounting groove is formed in the first rear shell, the bionic concave-convex front edge wing shell comprises a bionic concave-convex front edge and a second rear shell, and a second mounting groove is formed in the second rear shell;
The prototype front edge is fixed with the first rear shells through fixing screws, the number of the first rear shells is two, and the first rear shells are connected with the first wing ribs through the first mounting grooves; the bionic concave-convex front edge is fixed with the second rear shells through fixing screws, the number of the second rear shells is two, and the second rear shells are connected with the second wing ribs through the second mounting grooves;
The bionic concave-convex front edge comprises two design parameters, the wavelength is along the length direction, the amplitude is along the height direction, and the bionic concave-convex front edge is arranged in a constant wavelength variable amplitude manner; wherein the wavelength is 10mm, and the amplitude satisfies 6 along the length direction sin(π/170X), wherein x represents the distance to the end;
The design of the bionic concave-convex wing comprises the following steps:
S1: the shape of the bionic concave-convex front edge refers to the bulge of the front edge of the whale pectoral fin of the seat head, and the size parameter of the concave-convex front edge is obtained by combining the design of the wing profile;
S2: the inhibition effect of the concave-convex front edge of the size parameter on the flutter of the wing with the large aspect ratio is measured through a wind tunnel experiment;
s3: and optimizing the size parameter of the concave-convex front edge for a plurality of times according to the test result, and finally determining the optimal concave-convex front edge size parameter for inhibiting flutter.
2. The aerodynamic structure for suppressing wing flutter based on a bionic concave-convex leading edge according to claim 1, wherein: the number of the through holes is five, and the five through holes are respectively arranged at four vertexes and center points of one end of the rectangular straight beam.
3. An optimization method for inhibiting wing flutter based on a bionic concave-convex front edge is characterized by comprising the following steps: the method comprises the following steps: s1: the shape of the bionic concave-convex front edge refers to the bulge of the front edge of the whale pectoral fin of the seat head, and the size parameter of the concave-convex front edge is obtained by combining the design of the wing profile;
S2: the inhibition effect of the concave-convex front edge of the size parameter on the flutter of the wing with the large aspect ratio is measured through a wind tunnel experiment;
s3: optimizing the size parameter of the concave-convex front edge for a plurality of times according to the test result, and finally determining the optimal concave-convex front edge size parameter for inhibiting flutter;
The optimal design of the concave-convex front edge size comprises 4 parameters, and the amplitude of the concave-convex front edge, which is positioned at a distance x from the wing root, on the wing is expressed as:
；
Wherein A (x) is the concave-convex front edge amplitude, x is the distance between the wing and the wing heel, x0 is the distance between the central position and the wing root, A0 is the maximum concave-convex amplitude, lambda is the wavelength, and L is the total width of the concave-convex front edge.
4. The optimization method for inhibiting wing flutter based on the bionic concave-convex leading edge according to claim 3, which is characterized in that: after the amplitude of the concave-convex front edge is determined, the front 1/4 part of the wing airfoil is taken as a contour, the contour is laid out as a guide line, the smooth bionic concave-convex front edge appearance is formed, the bionic concave-convex front edge is combined with the rear 3/4 part of the wing airfoil, and mounting holes are cut out for being embedded into a straight beam, so that the complete integral bionic concave-convex front edge wing is formed.
5. The optimization method for inhibiting wing flutter based on the bionic concave-convex leading edge according to claim 3, which is characterized in that: in the wind tunnel experiment in the step S2, whether flutter occurs is judged by measuring deformation and vibration of the wing and flow fields around the wing; the deformation and vibration of the wing are measured through a DIC (digital image correlation); the flow field around the wing is measured by particle image velocimetry PIV.
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| CN108382590A (en) * | 2018-02-24 | 2018-08-10 | 浙江天遁航空科技有限公司 | Composite wing unmanned plane |
| CN109050876A (en) * | 2018-07-13 | 2018-12-21 | 北京航空航天大学 | A kind of new micro unmanned plane using bionical wing |
| CN113669194A (en) * | 2021-08-09 | 2021-11-19 | 中国科学院工程热物理研究所 | Flow separation control method based on bionic concave-convex front edge structure |
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| US20060060721A1 (en) * | 2004-03-30 | 2006-03-23 | Phillip Watts | Scalloped leading edge advancements |
| US10858088B2 (en) * | 2016-08-31 | 2020-12-08 | David E. Shormann | Biomimetic airfoil bodies and methods of designing and making same |
| CN108974326B (en) * | 2018-06-28 | 2021-02-09 | 西安交通大学 | Bionic wave front edge wingtip winglet device |
| CN114198249A (en) * | 2021-12-10 | 2022-03-18 | 华北电力大学（保定） | Wind turbine wing section structure with bionic pneumatic elastic sheet |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108382590A (en) * | 2018-02-24 | 2018-08-10 | 浙江天遁航空科技有限公司 | Composite wing unmanned plane |
| CN109050876A (en) * | 2018-07-13 | 2018-12-21 | 北京航空航天大学 | A kind of new micro unmanned plane using bionical wing |
| CN113669194A (en) * | 2021-08-09 | 2021-11-19 | 中国科学院工程热物理研究所 | Flow separation control method based on bionic concave-convex front edge structure |
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