Method for expanding volume of wave rider by using cubic polynomial

Abstract

The invention relates to a method for expanding the volume of a wave rider by using a cubic polynomial, which is implemented by keeping the lower surface of the wave rider unchanged, constructing a convex upper surface by using the cubic polynomial, and replacing the upper surface tracked in a free flow to increase the volume. A modeling contour line of the upper surface is set to comprise a central keel line and a cross section section line which are expressed by cubic polynomials, and coefficients of the polynomials are determined by positions and slopes of a head point and a tail point. Anexpression form of the upper surface can be obtained by combining the front edge contour line. On the basis that the smooth and continuous upper surface is guaranteed, the extractable design parameters comprise the trailing edge thickness, the head inclination angle and the side edge inclination angle, and the waverider appearances with different volumes can be generated by changing the design parameters. The method of expanding the upper surface enables the lift-drag ratio loss of the profile to be less than the lift-drag ratio loss of the profile when compared with the method of generating awave-rider lower surface with a greater thickness.

Description

technical field [0001] The invention relates to the field of hypersonic aerodynamic design, especially the layout form of waveriders. Background technique [0002] When the aircraft flies at hypersonic speed, there will be relatively strong shock waves. Generally speaking, the existence of shock waves leads to wave resistance, which increases the resistance at hypersonic speeds; but on the other hand, the pressure of the flow field after the wave increases. This characteristic The rational use of can improve the lift, and the waverider is exactly a typical shape utilizing this property. It prevents the leakage of high-pressure gas from the lower surface to the upper surface by attaching shock waves, thus dividing the flow field up and down along the leading edge into two independent problems: the lower surface is the waveriding surface, which is the main provider of lift; Streamlines are generated by flow tracing, and some scholars generate Mach expansion surfaces to furthe...

AI Technical Summary

Problems solved by technology

[0003] The waverider has attracted widespread attention at home and abroad due to its high lift-to-drag ratio, but its small volume has always limited its engineering application

In most studies, the method of expanding the volume of the waverider is to design the lower surface, increase the shock angle of the reference flow field, or modify the shock wave exit profile to increase the thickness of the lower surface of the waverider, but this treatment will greatly increase the resistance , and have an adverse effect on the installation of the intake duct

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