Rapid searching method for entropy layer characteristic value

Abstract

The invention discloses a rapid searching method for entropy layer characteristic values, and belongs to the field of aerodynamic flow stability, and the method comprises the steps: S1, obtaining a laminar flow field; s2, extracting a laminar flow calculation profile; s3, searching an entropy layer characteristic value; s4, identifying entropy layer stability physical understanding; and S5, verifying. According to the method, the effective eigenvalue of the entropy layer can be found, the problem that the eigenvalue cannot be found is avoided, the real physical understanding of the eigenvalue of the entropy layer can be identified, stability analysis of the entropy layer is facilitated, the method has the advantage of high calculation and finding speed of the eigenvalue of the entropy layer, and the time cost is reduced.

Description

technical field [0001] The invention relates to the field of aerodynamic flow stability, and more specifically, relates to a method for quickly searching for characteristic values ​​of entropy layers. Background technique [0002] When the aircraft flies at high speed, it will be strongly compressed to form a shock wave. In the head region, the shock wave is strongly bent causing its shape to become a kind of bow, this shock wave is called a bow shock. The gas behind the bow shock is stratified due to different flow characteristics. From the surface of the aircraft to the shock, the gas is divided into a boundary layer, an entropy layer, and an outer layer in sequence. The boundary layer is a thin layer formed by the adhesion of the gas to the surface due to the viscosity of the gas; the entropy layer is the area where high entropy gradient, high temperature, and low density gas are formed after the shock wave due to the bending of the shock wave; the outer layer is the bas...

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Problems solved by technology

[0004] The disturbance in the entropy layer can be obtained by solving the modal eigenvalues ​​of the linear stability equation, but its inflection point instability characteristics are not obvious, and its eigenvalue solutions are not easy to find, which has always been a headache for scholars.

The traditional method is to "get" the correct physical understanding by "spreading points widely", but it is often time-consuming and labor-intensive and not necessarily obtained. The main reasons are: 1) Blindly setting the frequency range increases unnecessary calculations ; 2) Blindly setting the disturbance wavelength interval, it is easy to miss the correct physical understanding; 3) It is impossible to judge whether the entropy layer eigenvalue solution is a real physical understanding

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