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How to estimate total time and timestep for unsteady simulations? |
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#1 |
New Member
Join Date: May 2013
Posts: 10
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Hi fellows,
I'm having the hardest time ![]() Some of the experimental data known that could help to carry out the unsteady simulation are: two Strouhal number based on bubble length (separation to reattachment point) and reference velocity, Uref = 25 m/s. The first Strouhal number describes the breathing motion of the bubble, St = 0.01 and the second one describes the emission of coherent structures in (by?) the shear layer, St = 0.35. Could anyone please give me a hint on how to get to see, for example, u' x t??? ![]() Thanks in advance! |
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#2 |
New Member
Join Date: May 2013
Posts: 10
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I have been using BSL EARSM model on CFX to steady simulation. This was the only model that best showed the flow pattern, compared to experiments (oil-film technique), in the upper wall of the wind tunnel test section in the region of the separated flow.
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#3 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,816
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You should do some careful research on turbulence models to help with this work. Most (if not all) 2 eqn turbuelnce models will be unsuitable for this as they have known deficiencies in getting separation bubbles the correct size. RSM models may help, but you may well have to use an LES style model.
You need to spend a merry day at the library doing a literature review on all this before starting, I would suggest.
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Tags |
separation bubble, timesteps, tsb, unsteady |
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