Local spikes in force coefficients -- CFD Online Discussion Forums

May 1, 2019, 15:14

Local spikes in force coefficients

sjsivabharathy

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jawahar sivabharathy

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Hi all,
I'm trying to solve an unsteady flow at Re = 100.
I use pisofoam solver with a time step size dt = 0.001.
My residuals are so small and maximum Courant number is 0.2.
The force coefficients on the model is periodic but sometime I get these
spikes in both Cl and Cd. I have attached them.
Could someone please explain me why this kind of behavior occurs.
I will provide any additional information if required.
Thanks,
Jawahar.

Attached Images

	cl.png (24.2 KB, 9 views)
	cd.png (15.0 KB, 6 views)

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