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Summary: TEMPORAL SECOND-ORDER ACCURACY OF
SIMPLE-TYPE METHODS FOR INCOMPRESSIBLE
UNSTEADY FLOWS
Ming-Jiu Ni and Mohamed A. Abdou
UCLA MAE Department, Engineering IV,
Los Angeles, California, USA
SIMPLE-type methods are presented in a more concise formulation. This formulation is
used to analyze temporal accuracy for unsteady flows. Detailed error formulations are
given. Analysis shows that SIMPLE-type methods have second-order temporal accuracy if a
second-order temporal updating technique is employed to update both the convective and
diffusion terms. Two algorithms for unsteady flows are presented. Algorithm A is an
iteration method, which will cost more time than algorithm B, a noniteration algorithm.
Also several second-order updating techniques are presented. A classical validation example
is employed to validate the temporal accuracy in this article. A new four-step SIMPLE-type
method is presented, in which the pressure Poisson equation, not the pressure difference
Poisson equation is solved.
1. INTRODUCTION
The dimensionless unsteady incompressible NavierStokes equations in
primitive variables can be written as
@u
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