|November 27, 2003, 10:11||
Defining time step size
OK, this is a simple problem, that I haven't got my head round,
I have a test case to model, which has a characteristic height 0.066m (as used for E in K-E). For running the URANS sims for vortex shedding, in kelvin-helmhotz (K-H) form. I have taken the size of the first K-H instability, and calculated the time the free-stream velocity takes to pass over it, gave it 30 steps over the motion, which results in a timestep of 0.000006 sec. Is that too small?
The Cd and Cl traces are extremely unsteady, varying between 10 and 0 for Cl( high as 30 - -15 near start) and 5 and 0 for Cd (30 - -5 near start).
Length of 1st K-H approx = 0.005423m (0.000180 sec/periodic motion) Length of test case = 0.371m vel = 30m/s (Re approx 9*10^5)
Thanks for any advice.
|Thread||Thread Starter||Forum||Replies||Last Post|
|How to write k and epsilon before the abnormal end||xiuying||OpenFOAM Running, Solving & CFD||8||August 27, 2013 15:33|
|Time step size, number of time steps and max iterations per time step||guido_88||FLUENT||4||August 30, 2012 14:49|
|Orifice Plate with a fully developed flow - Problems with convergence||jonmec||OpenFOAM Running, Solving & CFD||3||July 28, 2011 05:24|
|Problems in compiling paraview in Suse 10.3 platform||chiven||OpenFOAM Installation||3||December 1, 2009 08:21|
|Transient simulation not converging||skabilan||OpenFOAM Running, Solving & CFD||12||September 17, 2007 17:48|