低Prandtl数水平流体层自然对流的振荡和分歧

BIFURCATION AND OSCILLATION OF NATURAL CONVECTION IN A HORIZONTAL LAYER OF LOW PRANDTL NUMBER FLUID

本文用具有QUICK方案的有限差分法对底部加热的低Prandtl数水平流体层自然对流换热进行了数值计算，研究了这种问题中存在的振荡和分歧问题。结果显示，在Ra的一定取值区间，有4涡型流场和5涡型流场两个解的分支。但在这个区间以外，最终的结果没有出现分歧。在所发现的两个解的分支中，问题由稳态转变为非稳态的临界Racr是不同的。

Bifurcation and oscillation were studied for the natural convection in a horizontal layer of low Prandtl number fluid using SIMPLE algorithm with a kind of QUICK scheme. It can be found that the numerical results are related to the initial conditions adopted for the calculation and the flow fields have the same flow patterns as the initial when Rad<Ra<Rau. When Ra>Racr, the fluid flow and heat transfer become unsteady. Racr isrelated to the flow pattern of initial flow field.