Method for fluid simulation by using Boltzmann equation

Abstract

The invention discloses a method and a system for fluid simulation by using Boltzmann equation. The method for fluid simulation by using Boltzmann equation comprises the following steps: surface meshenvelope treatment; generating spatial Cartesian grids; full transient flow field calculation. This method calculates the molecular cluster density function of each point in the flow field at different time. The particle distribution function satisfies the lattice Boltzmann equation. The method for simulating a fluid by using the Boltzmann equation adopts a full-detail geometric model, does not need to be simplified, and ensures the authenticity and accuracy of the simulation result; full transient algorithm, accurate calculation of the real transient aerodynamic force; accurate solution of separated flow at hgh angle of attack (or stall state); time-marching explicit algorithm, so that there is no divergence problem in the solution process; high-precision automatic solution, so that no manual intervention is needed and high stability is achieved.

Description

Technical field: [0001] The invention relates to a simulation method applied to fluid mechanics, in particular to a computer simulation method applied to fluid mechanics. Background technique: [0002] At present, in the field of simulation of fluid mechanics, most of the traditional calculation methods first discretize the macroscopic control equations, then use some numerical method to solve the discrete equations, and finally obtain the macroscopic physical quantities. The traditional simulation methods based on N-S equation (Navier-Stokes equation, describing the conservation of momentum of viscous incompressible fluid, referred to as N-S equation) and steady-state approximation have some shortcomings: [0003] A lot of manual simplification work is required: the geometric model must be simplified, the method cannot directly calculate the full-detailed calculation model, and cannot simulate the transient flow field characteristics of the real model. For complex models o...

AI Technical Summary

Problems solved by technology

[0004] Steady-state algorithm: The traditional N-S equation simulation method uses an iterative solution algorithm to approach the steady-state solution result, which cannot calculate unsteady aerodynamic loads such as flutter problems caused by transient pressure fluctuations, and also cannot solve the aerodynamic noise of automobiles and warships well. Ship's hydrodynamic noise and other issues

[0005] Approximate solution: The traditional N-S equation simulation method is more suitable for solving the conventional non-separation flow, and cannot accurately calculate the large separation flow at a large angle of attack or stall state, nor can it accurately calculate the dynamic aerodynamic force during the flight of the aircraft

[0006] Solution accuracy: The calculation result accuracy of the traditional N-S equation simulation method is related to the grid, and the quality of the grid division is related to the experience of the analyst. The low quality of the grid division will lead to large errors in the calculation results, and even make the calculation results Divergence, the calculation results are heavy on human factors, and there are big problems in the uniqueness, convergence and stability of the calculation results

Images