VortexShedding Flow at HighReynolds Number
Hi Dear friends,
In recent days, I have been simulated the behaviour of the flow behind a square cylinder. My code uses RANS and two KEpsilon models (the standard and LowReynolds). With both the models, the twovortex row does not persist in the wake. My question is: is this behaviour correct? Thanks. Ferreira. 
Re: VortexShedding Flow at HighReynolds Number
(1). Fill your bath tub with water. (2). Move the square cylinder stick through the surface of the water in a steady stroke. (3). Observe the wake behind the square cylinder. (4). Spread some baby powder on the surface to aid the observation. Estimate the Reynolds number and check the result. (5). Effect of Reynolds number? You will have to run a real test to find out.

Re: VortexShedding Flow at HighReynolds Number
Your RANS simulation is doing what it is designed to do with the keps. (an eddy viscosity) model  all unsteady turbulent motion, and the unsteady vortex shedding, is smeared out with the large eddy viscosities thrown into the simulation just behind your square through the use of the keps. model. As a result, the unsteadiness that occurs in real life can't be reproduced
At best, what you can expect from your RANS simulation using the turbulence model is something that is close to the long time average of the real flow. 
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