求解流动和传热问题的一种新的全隐算法-CLEAR(下)

A NEW FULLY IMPLICIT ALGORITHM FOR SOLVING FLUID FLOW AND HEAT TRANSFER PROBLEMS-CLEAR (Ⅱ)

本文上篇阐述了CLEAR算法的推导过程和计算步骤,本文下篇通过五个二维不可压缩流动和传热的算例,对CLEAR算法和SIMPLER算法进行了比较,比较的内容为,在相同的收敛条件下, CLEAR算法和SIMPLER算法收敛所需的迭代次数的比值和对应的CPU时间的比值,以及这两个比值和时步倍率的关系,从而进一步研究了CLEAR算法的健壮性。计算结果表明,CLEAR算法可以在很大程度上加速迭代收敛,就所比较的算例而言,其可以节省迭代次数31％-85％,节省CPU时间17％-78％,而且该算法的健壮性可以通过引入第二松弛因子而得以提高。

The derivation process and calculation procedure of CLEAR algorithm is formulated in the first part of this paper, and in this part. The SIMPLER and CLEAR algorithm are compared with five two dimensional numerical examples of incompressible fluid flow and heat transfer problems on the subject of the ratio of the iteration number and the corresponding consumed CPU time for obtaining a converged solution under the same converging condition to investigate the robustness characteristic of the new algorithm. It turns that CLEAR can appreciably enhance the convergence rate which can save the iteration number of 31%~85% and 17%~78% for CPU time compared to SIMPLER algorithm for the five problems tested, and the robustness can be improved by the second relaxation factor.