High aspect ratio problem....

smjl · October 23, 2011, 00:10

I am currently solving Euler eqn from my compressible SIMPLE algorithm using structured grids. On some high-aspect ratio grids, convergence is slow and it sometimes fails. I found that happened when the gradient of variable( u v p ...) is large where the aspect ratio of grid is also large. It's just a small region, but make the convergence slow. then i changed second order upwind scheme to first upwind , everything became ok. I don't known why? Does second order scheme makes that happened? and how should i do to solve this problem if i want to get second order accuracy?

Far · October 23, 2011, 06:48

reduce the CLF number

October 23, 2011, 00:10	High aspect ratio problem....	#1
smjl New Member lei.zhao Join Date: Nov 2009 Posts: 1 Rep Power: 0	I am currently solving Euler eqn from my compressible SIMPLE algorithm using structured grids. On some high-aspect ratio grids, convergence is slow and it sometimes fails. I found that happened when the gradient of variable( u v p ...) is large where the aspect ratio of grid is also large. It's just a small region, but make the convergence slow. then i changed second order upwind scheme to first upwind , everything became ok. I don't known why? Does second order scheme makes that happened? and how should i do to solve this problem if i want to get second order accuracy?

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October 23, 2011, 06:48		#2
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	reduce the CLF number