Bulk velocity

mcaro · August 17, 2011, 15:10

Hello,

i am trying to simulate a turbulent flow around a wall-mounted cube using the kappa-epsilon model and, in a future, the RNG- kappa-epsilon model.

The Reynolds number based on the bulk velocity and the channel height (Re=U_b* H/nu, U_b bulk velocity, H cube height and nu cinematic viscosity) is Re=40000.

But , excuse me for this question: How i compute the bulk velocity?

I am using to simulate this problem an in-house code for turbulent flows , for this i need the inflow velocity , Uo ,to start the simulation. The H value is done as the Re above mentioned.

The initial and boundary conditions are taken from Lakehal and Rodi,"Calculation of the flow past a surface-mounted cube with two-layer turbulence models", 1997.

regards
Miguel

mcaro · August 18, 2011, 11:02

Turbulent flows, S. Pope, "wall flows", p.p.264-280.

Rami · August 22, 2011, 07:23

$u_{i,bulk} = \int_{\partial V} \rho u_i dA / \int_{\partial V} \rho dA$

JR22 · March 19, 2013, 08:06

Does my question answer your question?

I asked (paraphrasing):

Quote:

The stressComponents postprocessing utility (utilities/postProcessing/stressField/stressComponents.C) provides a Ub vector (x,y,z) mapped on surfaces. What is the physical meaning of Ub?

I know this is a pretty old thread, but this might give it a happy ending.

August 17, 2011, 15:10	Bulk velocity	#1
mcaro New Member Miguel Caro Join Date: Apr 2010 Posts: 26 Rep Power: 16	Hello, i am trying to simulate a turbulent flow around a wall-mounted cube using the kappa-epsilon model and, in a future, the RNG- kappa-epsilon model. The Reynolds number based on the bulk velocity and the channel height (Re=U_b* H/nu, U_b bulk velocity, H cube height and nu cinematic viscosity) is Re=40000. But , excuse me for this question: How i compute the bulk velocity? I am using to simulate this problem an in-house code for turbulent flows , for this i need the inflow velocity , Uo ,to start the simulation. The H value is done as the Re above mentioned. The initial and boundary conditions are taken from Lakehal and Rodi,"Calculation of the flow past a surface-mounted cube with two-layer turbulence models", 1997. regards Miguel

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August 18, 2011, 11:02		#2
mcaro New Member Miguel Caro Join Date: Apr 2010 Posts: 26 Rep Power: 16	Turbulent flows, S. Pope, "wall flows", p.p.264-280.

August 22, 2011, 07:23		#3
Rami Senior Member Rami Ben-Zvi Join Date: Mar 2009 Posts: 155 Rep Power: 17	$u_{i,bulk} = \int_{\partial V} \rho u_i dA / \int_{\partial V} \rho dA$