Hypersonic transverse flow transition prediction method considering surface roughness effect

Abstract

The invention discloses a hypersonic transverse flow transition prediction method considering a surface roughness effect. The hypersonic transverse flow transition prediction method is based on the fact that a critical transverse flow Reynolds number and surface roughness meet a logarithmic relationship, and based on hypersonic wind tunnel experimental data, transition critical momentum thicknessReynolds numbers of different roughness under a hypersonic condition are obtained through CFD layer solution, a least square method is adopted to solve a relation coefficient, a criterion relational expression is obtained, and prediction of transverse flow transition is achieved by adding a transverse flow source item DSCF into an existing gamma-Retheta t transition model momentum thickness transport equation. Due to the fact that a gamma-Retheta t transition model is a localization model, the transverse flow criterion ReSCF is obtained through iteration, the momentum thickness Reynolds numberdoes not need to be solved through integration, and localization is achieved. Therefore, the method does not relate to calculation or calling of non-local amount, the prediction technology achieves complete localization, and the method is suitable for large-scale parallel calculation.

Description

Technical field [0001] The invention belongs to the technical field of flow prediction, and in particular relates to a method that can predict the transition position of hypersonic cross flow under different surface roughness. Background technique [0002] When a fluid (gas or liquid) flows around a solid, the interaction area between the fluid and the solid mainly occurs in the thin surface 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 are huge differences between these two flow regimes in terms of aerodynamic distribution, thermal distribution and mixing effects on the surface of the object. The process of changing from laminar flow to turbulent flow is called transition, and transition prediction is of great significance to the design of aerospace vehicles. The transition process is a complex nonlinear process affected by multi-factor coupling. According to the mod...

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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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