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hyderkhan74 July 11, 2012 07:47

Log law for unsteady velocity profile
 
Hi
I want to simulate the unsteady wind flow over a house. For steady simulation I use Log law velocity profile but I couldn`t find a formula for the Unsteady simulation where the wind speed is changes with time. so I wonder what is the formula for such problem ?

FMDenaro July 11, 2012 10:02

Quote:

Originally Posted by hyderkhan74 (Post 370794)
Hi
I want to simulate the unsteady wind flow over a house. For steady simulation I use Log law velocity profile but I couldn`t find a formula for the Unsteady simulation where the wind speed is changes with time. so I wonder what is the formula for such problem ?


no analytical law exists for unsteady turbulent velocity, the log-law has statistical meaning for a flow in energy equilibrium (production=dissipation) such that the time derivative statistically vanishes.
If you have a flow that increases in time I suggest using LES with a grid resolving the boundary layer, however this is computational expensive.


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