# turbulent flow around cylinder

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May 19, 2013, 07:57
turbulent flow around cylinder
#1
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kazem
Join Date: Mar 2012
Location: kazeroun,iran
Posts: 3
Rep Power: 7
I have been studing external flow around a cylinder at Re=10e6 ,Ihave been using k-e model. pressure coefficient (that attach below) is incorrect !
because pressure coefficient is larger than one.
my problem is putting pressure on the referrence values??
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 May 29, 2013, 06:06 #2 Senior Member   Rami Ben-Zvi Join Date: Mar 2009 Posts: 148 Rep Power: 10 Hi kazem azizem, AFAIK, the drag force is Fd = 1/2 * Rho * U^2 * Cd. Therefore, if you normalize everything consistently, (e.g., density, velocity and pressure by rho0, U0 and 1/2 * rho0 * U0^2, respectively), you should be OK. Am I missing something? Rami

May 29, 2013, 16:59
#3
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kazem
Join Date: Mar 2012
Location: kazeroun,iran
Posts: 3
Rep Power: 7
Quote:
 Originally Posted by Rami Hi kazem azizem, AFAIK, the drag force is Fd = 1/2 * Rho * U^2 * Cd. Therefore, if you normalize everything consistently, (e.g., density, velocity and pressure by rho0, U0 and 1/2 * rho0 * U0^2, respectively), you should be OK. Am I missing something? Rami
hi Rami azizam
what do you mean normalize velocity or density consistly?
Did you mean dimensionless expressions of velocity and pressure ...?

 May 30, 2013, 13:05 #4 Senior Member   Rami Ben-Zvi Join Date: Mar 2009 Posts: 148 Rep Power: 10 Kazem Jun, Yes, that is what I mean. After all, Cd is mearly a nondimensional form of the drag force, Fd. I am not sure though if the form I had used (Fd = 1/2 * Rho * U^2 * Cd, in which case you get Cd=2 for an infinite plate normal to the flow) is the conventional or is it without the 1/2. Khoda hafes, Rami

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