CN-121980692-A - Corrugated wall wing airfoil and design method thereof

CN121980692ACN 121980692 ACN121980692 ACN 121980692ACN-121980692-A

Abstract

The invention relates to a corrugated wall wing airfoil and a design method thereof, which are applied to an unmanned aerial vehicle and are characterized in that a corrugated wall is arranged in a chord-wise area of the upper surface of the airfoil, the corrugated wall is used for inducing the boundary layer on the upper surface of the airfoil to transition in advance and inhibiting the generation of laminar flow separation bubbles, the corrugated wall is of a sine function corrugated structure, and the sine curve of the corrugated wall meets the following conditions: . The sine corrugated wall surface structure with specific geometric parameters is arranged in the chord direction middle-rear area of the upper surface of the wing airfoil, so that the local pressure distribution of the airfoil surface is changed, the boundary layer is induced to generate transition in advance, the generation of laminar flow separation bubbles is inhibited, the wall friction resistance and the pressure difference resistance are reduced, and the problem that the drag reduction effect of the low-altitude low-speed unmanned wing is limited is solved.

Inventors

SUN SHIWEI
Wei Zexuan
WU YIHANG
XU HEYONG

Assignees

上海伟视清数字技术有限公司
河南九如科技有限责任公司

Dates

Publication Date: 20260505
Application Date: 20260409

Claims (10)

1. The design method of the corrugated wall wing profile is characterized by comprising the following steps of: S1, acquiring geometrical coordinate data of an airfoil, and establishing a geometrical model of the airfoil; s2, in the chord direction section of the upper surface of the airfoil To the point of Built-in waver function region, called waver region, at the original airfoil upper surface baseline And superposing a sine disturbance function to form a corrugated wall structure, wherein the coordinates of the corrugated profile of the corrugated wall structure satisfy the following conditions: Wherein, the Is the coordinates of the corrugated profile, Is the coordinates of the upper surface of the original airfoil, In the form of an amplitude of the wave, As a function of the wavelength(s), In order to be the starting position of the corrugation, In the end position of the corrugation, Is a chord coordinate; S3, carrying out smoothing treatment on the corrugated surface in the step S2 so as to realize smooth transition between the corrugated area and the smooth surface of the original airfoil; s4, performing aerodynamic performance evaluation on the corrugated airfoil subjected to the photoside treatment to obtain aerodynamic performance parameters; S5, carrying out corrugated structure parameter optimization: wherein the corrugation parameters include a corrugation start position Corrugated end position Amplitude of wave Wavelength of Changing the initial position of the corrugation Corrugated end position Amplitude of wave Wavelength of Repeatedly executing the step S2 to the step S4 to obtain pneumatic performance parameters corresponding to different parameter combinations; and setting parameter constraint conditions as follows: On the premise of meeting the constraint condition, determining the ripple structure parameters meeting the target aerodynamic performance requirement.
2. The method of designing a corrugated wall airfoil according to claim 1, wherein in step S3, the corrugated region is locally smoothed by cubic B-splines to make both ends of the corrugations And (3) with The first derivative and the second derivative are continuous.
3. The method of designing a corrugated wall airfoil according to claim 1, wherein the aerodynamic performance evaluation in step S4 is performed by numerical simulation in which the surrounding flow field of the airfoil is gridded and locally encrypted in the chord direction in the corrugated area so that the number of nodes arranged in a single corrugated period is greater than 10.
4. A method of designing a corrugated wall wing airfoil as claimed in claim 3 in which in said numerical simulation the first layer grid height near the airfoil surface is set to 。
5. The method for designing a corrugated wall wing airfoil according to claim 3, wherein the numerical simulation uses a k-kl- ω three-way transition model to perform the airfoil bypass numerical simulation.
6. A corrugated wall wing airfoil for an unmanned aerial vehicle, which is characterized in that the corrugated wall wing airfoil designed by the design method of the corrugated wall wing airfoil as claimed in any one of claims 1 to 5 is provided with a corrugated wall in a chord-wise area on the upper surface of the airfoil, the corrugated wall is used for inducing the boundary layer on the upper surface of the airfoil to transition in advance and inhibiting the generation of laminar flow separation bubbles, the corrugated wall is of a sine function corrugated structure, and the sine curve of the corrugated wall meets the following conditions: Wherein, the In the form of an amplitude of the wave, In the case of a corrugated wavelength, Is the chordwise coordinate.
7. The corrugated wall wing airfoil according to claim 6, wherein said corrugated wall is disposed in the area of 50% to 80% of the airfoil upper surface chord wise direction.
8. The corrugated wall wing airfoil according to claim 7, wherein said airfoil is a NACA4412 airfoil having an airfoil chord c of 100 mm and an amplitude Mm, wavelength mm。
9. The corrugated wall wing airfoil of claim 8 wherein said corrugated structure is a concave sinusoidal corrugated structure having its sine wave crest tangential to said airfoil upper surface.
10. The corrugated wall wing airfoil of claim 6 wherein said corrugated wall is formed by a laser machining or precision milling process.

Description

Corrugated wall wing airfoil and design method thereof Technical Field The invention relates to the field of aviation drag reduction technology and passive flow control, in particular to a corrugated wall wing airfoil and a design method thereof. Background With the wide application of unmanned aerial vehicle in fields such as military reconnaissance, survey and drawing monitoring, logistics transportation, etc., have put forward higher demands to unmanned aerial vehicle's range, duration and flight efficiency. Under low-altitude and low-speed flight conditions, aerodynamic drag on the surface of the unmanned aerial vehicle wing becomes an important factor affecting flight performance, and therefore, reducing aerodynamic drag by improving the wing airfoil structure becomes an important research direction in current unmanned aerial vehicle designs. The drag reduction techniques currently in common mainly include active flow control techniques and passive flow control techniques. Active flow control techniques typically achieve drag reduction by applying external energy to the airfoil surface, such as by blowing, suction, or plasma control, to alter the boundary layer flow conditions. However, the technology generally has the problems of complex structure, higher energy consumption, high system reliability requirement and the like, and has higher popularization difficulty in application scenes such as a small unmanned aerial vehicle and the like. In contrast, the passive flow control technology does not need additional energy input, can regulate and control the air flow by changing the geometric structure of the surface of the wing, and has the advantages of simple structure, high reliability, low maintenance cost and the like. Currently common passive flow control structures include transition zones, pit arrays, trench structures, saw tooth trailing edge structures, and the like. However, most of these structures are designed for high reynolds number aircrafts, and the drag reduction effect of the unmanned aerial vehicle is still limited under the working condition of the unmanned aerial vehicle with low altitude and low speed. The corrugated wall structure was initially applied to the field of heat exchanger enhanced heat transfer and was subsequently gradually introduced into aviation drag reduction studies. By forming periodic corrugation structures on the wall surface, local vortex structures can be induced in the boundary layer, and low-speed flow areas are formed in the trough areas, so that the shearing stress of the wall surface is reduced, the local pressure distribution is changed to a certain extent, and adverse flow separation phenomena can be restrained. However, the drag reduction effect of the corrugated structure has higher sensitivity to parameters such as corrugated wavelength, amplitude, arrangement position and the like, and if the parameter design is not reasonable, aerodynamic drag may be increased instead. Disclosure of Invention It is an object of the present invention to provide a corrugated wall airfoil and method of designing the same that addresses or at least alleviates one or more of the above-identified problems and other problems of the prior art. In order to achieve the foregoing object, according to a first aspect of the present invention, there is provided a corrugated wall wing airfoil for use in an unmanned aerial vehicle, wherein a corrugated wall is provided in a chordwise region of an upper surface of the airfoil, the corrugated wall is used for inducing a boundary layer on the upper surface of the airfoil to transition in advance and suppressing generation of laminar flow separation bubbles, the corrugated wall is a sine function corrugated structure, and a sine curve of the corrugated wall satisfies: Wherein, the In the form of an amplitude of the wave,In the case of a corrugated wavelength,Is the chordwise coordinate. In a corrugated wall wing airfoil as previously described, optionally, the corrugated wall is disposed in the area of 50% to 80% of the airfoil upper surface chord wise direction. In the corrugated wall wing airfoil as described above, optionally, the airfoil is a NACA4412 airfoil having an airfoil chord length c of 100 mm, amplitudeMm, wavelengthmm。 In the corrugated wall wing airfoil as described above, optionally, the corrugated structure is a concave sinusoidal corrugated structure with its sine wave crest tangential to the airfoil upper surface. In the corrugated wall wing airfoil as described above, the corrugated wall is optionally formed by laser machining or precision milling processes. According to a second aspect of the present invention, there is also provided a method of designing a corrugated wall airfoil, comprising the steps of: S1, acquiring geometrical coordinate data of an airfoil, and establishing a geometrical model of the airfoil; s2, in the chord direction section of the upper surface of the airfoil To the point ofBuilt-in waver