A boundary layer separation-induced transition prediction method, device, equipment and medium

Abstract

The invention discloses a boundary layer separation-induced transition prediction method, device, equipment and medium in a wide speed range. and incoming flow parameters, using the improved k‑ω‑γ transition model to predict the separation-induced transition of the surface boundary layer of the aircraft; the improved k‑ω‑γ transition model includes: (1) by constructing a damping function for the effective (2) Construct a pressure gradient factor based on local variables as the separation transition indicator factor; (3) Construct a separation intermittent factor that can reflect the separation effect of the boundary layer based on the pressure gradient factor, thus realizing k‑ω‑γ Separation of patterns induces transition prediction functions. The invention can be simultaneously applied to the separation-induced transition prediction of subsonic velocity, transonic velocity and supersonic velocity. The invention is entirely based on local variables and Galilean invariants, and can be applied to massively parallel modern CFD programs based on coordinate system motion.

Description

technical field [0001] The invention belongs to the technical field of transition prediction, and in particular relates to a method, device, equipment and medium for boundary layer separation induced transition prediction in a wide speed domain. Background technique [0002] Transition is a continuous physical process in which the flow evolves from a stratified stable laminar state to a chaotic turbulent state. The transition process of the boundary layer contains various forms of instability. The currently recognized instability modes mainly include: the first, second and second modes in the mode growth stage. Modes, etc.; cross-flow modes appearing in three-dimensional flow; separation instability induced by flow separation and Klebanoff modes excited in Bypass transition, etc. Among them, separation-induced transition is widely present in the boundary layer flow of turbine blades, low-speed airfoils, hypersonic vehicles and other shapes, and is crucial to the evolution ...

AI Technical Summary

Problems solved by technology

This greatly limits the application of the model in the boundary layer transition prediction in the wide velocity domain;

[0005] 2. Most of the existing models are not based on Galilean invariants, so they cannot be applied to the situation where the object plane moves relative to the coordinate system;

[0006] 3. The solution of non-local variables such as momentum thickness and boundary layer thickness is inevitably introduced into the existing model construction

These non-local variables require integral solutions, which are difficult to implement in CFD programs based on unstructured grids and modern massively parallel computing;

[0007] 4. The existing model lacks the consideration of the separation-induced transition mechanism, which makes it necessary to recalibrate the model parameters when predicting the boundary layer separation transition for different shapes, and the prediction accuracy is reduced, and in the transition prediction of the actual three-dimensional shape often fails

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