A hypersonic cross-flow transition prediction method considering the effect of surface roughness

Abstract

The invention discloses a hypersonic cross-flow transition prediction method considering the effect of surface roughness. The hypersonic cross-flow transition prediction method is based on making the critical cross-flow Reynolds number and surface roughness satisfy a logarithmic relationship, and based on hypersonic wind tunnel experiments Data, through the CFD laminar flow solution to obtain the Reynolds number of the transition critical momentum thickness under hypersonic conditions with different roughness, the least square method is used to solve the relationship coefficient, and the criterion relation is obtained, and through the existing γ‑Re θt The cross-flow source term D is added to the momentum thickness transport equation of the transition model SCF Realize the prediction of cross flow transition. Due to γ‑Re θt The transition model itself is a localized model, while the cross-flow criterion Re SCF It is obtained through iteration, and it does not need to integrate to solve the momentum thickness Reynolds number, and also realizes localization. Therefore, this method does not involve the calculation or invocation of non-local quantities, and the prediction technology is completely localized, which is suitable for large-scale parallel computing.

Description

technical field [0001] The invention belongs to the technical field of flow prediction, and in particular relates to a method capable of predicting the transition position of hypersonic cross flow under different surface roughness. Background technique [0002] When the fluid (gas or liquid) flows around the solid, the interaction area between the fluid and the solid mainly occurs in the thinner boundary layer outside the solid wall, which is also called the boundary layer. Boundary layer flow has two states: laminar flow state and turbulent flow state. There is a huge difference between the two flow states in terms of aerodynamic distribution, thermal distribution and mixing on the surface of the object. The process of changing from laminar flow to turbulent flow is called transition, and the prediction of transition is of great significance to the design of aerospace vehicles. The transition process is a complex nonlinear process affected by multi-factor coupling, which ...

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Problems solved by technology

The strong discontinuity characteristics and wall temperature effect of hypersonic flow, as well as the three-dimensional rotating body shape different from the low-speed airfoil, make the traditional low-speed cross-flow transition prediction technology no longer applicable in hypersonic flow.

[0007] 2. Existing cross-flow transition prediction techniques are rarely able to achieve complete localization

The cross-flow transition criterion based on the cross-flow Reynolds number needs to search for the maximum cross-flow velocity and the position in the boundary layer corresponding to a specific velocity in the whole field, so this criterion and its corresponding cross-flow transition prediction technology cannot be fully localized

It is difficult to implement and promote non-localized prediction technology in large-scale parallel computing, which affects computing efficiency

[0009] 3. The existing hypersonic cross-flow transition prediction technology level does not consider the influence of surface roughness on cross-flow transition

[0031] The above-mentioned entire transition prediction system including the cross-flow prediction module can achieve localization and introduce roughness effects, but it is currently only applicable to subsonic cross-flow transition prediction

In the prediction of hypersonic cross flow, there will be a problem that the cross flow does not start, that is, the subsonic cross flow transition model cannot predict the cross flow transition under hypersonic conditions

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