Semi‐implicit and explicit finite element schemes for coupled fluid/thermal problems
Semi‐implicit and explicit finite element schemes for coupled fluid/thermal problems
复制标题
DOI：
10.1002/nme.1620340218
复制
发表时间：
1992-03
影响因子：
2.9
通讯作者：
B. Ramaswamy;T. Jue;J. Akin
中科院分区：
文献类型：
--
作者：
B. Ramaswamy;T. Jue;J. Akin
在一系列数值试验的基础上，对用于不可压缩流动计算的两种纯显有限元方法和一种半隐式有限元方法进行了比较研究。采用“分离”的方法，按顺序考虑运动方程。对配方的基本概念和特点以及所使用的解决方法进行了详细的技术描述。研究了Chorin投影算法的各种修改，特别是它们对稳定性和精度的影响。与显式方法相比，随着雷诺数的增加，半隐式方法的稳定性受到的限制较小。在大时间步长时，也降低了人工粘度，获得了更高的精度。高雷诺数下的空腔流动和绕后台阶流动问题以及高瑞利数下的自由对流问题的数值解表明了本文所讨论方法的有效性。结果表明，与显式方法相比，半隐式方法所需的迭代次数更少，并且通过与现有方法的比较，保证了本方法的精度。
A comparative investigation, based on a series of numerical tests, of two purely explicit and one semi-implicit finite element methods used for incompressible flow computation is presented. The ‘segregated’ approach is followed and the equations of motion are considered sequentially. The fundamental concepts and characteristics of the formulations and the solution methodology used are described in technical detail. Various modifications to Chorin's projection algorithm are investigated, particularly with respect to their effects on stability and accuracy. The stability of the semi-implicit method is shown to be less restrictive when compared to the explicit methods as the Reynolds number increases. At large time steps the artificial viscosity is also reduced and higher accuracy is obtained. The performance of the methods discussed in this paper is illustrated by the numerical solutions obtained for the cavity flow and flow past a rearward-facing step problems at high Reynolds numbers, and free convection flow problem at high Rayleigh numbers. It is shown that the semi-implicit method needs fewer iterations than the explicit methods, and the accuracy of the present methods is guaranteed by comparison with the existing methods.