[kazem]

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??

[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

[kazem]

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 ...?

[Rami]

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