Uniform Flow around a cylinder

zhoubinwx · March 29, 2009, 12:18

Hi Santos,

That's great to hear from you. I think your computational domain will be smaller than mine. (maybe there will be difference for the influence from cylinder and from sphere).

I have other analytical solution for sphere. Please let me know if you need.

Best regards,

Bin

santos · March 29, 2009, 14:58

Hi Bin,

I just finished a simulation with 1/40 ratio between sphere radius and channel height, and my Cd value deviates just 3% from Stokes law (in my previous attempts the error was higher for smaller channel height).

What analytical solution you have?

Regards,
Jose Santos

zhoubinwx · March 30, 2009, 14:14

Hi, Santos,

The expression of different analytical solutions for sphere case is in my Vista system. I will email you tonight. Please accept it from Italy

Best regards,

Bin

marico · March 31, 2009, 02:54

Hi FOAMers,

I'm doing the same things around the cylinder. I previously ran a case with k-Epsilon around 1E+5 < Re < 1E+6 sucessfully.
Now I try to do the same with kOmegaSST model, but the solution is not fine, the forceCoefficients are not steady. Can someone please help me with the boundary conditions for k and omega ?! What about zeroGradient a Inlet for such a case?

Thank You
Marco

lin · March 31, 2009, 11:50

I'm not sure,but generally it seems to be a general rule to prescribe inlet values of turbulent quantites.You could guess the value or use the value from experimental results.

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March 29, 2009, 12:18		#41
zhoubinwx Senior Member ZHOU Bin Join Date: Mar 2009 Location: Nanjing/Torino, Nanjing/Piemente, China/Italy Posts: 164 Rep Power: 17	Hi Santos, That's great to hear from you. I think your computational domain will be smaller than mine. (maybe there will be difference for the influence from cylinder and from sphere). I have other analytical solution for sphere. Please let me know if you need. Best regards, Bin

March 29, 2009, 14:58		#42
santos Senior Member Jose Luis Santos Join Date: Mar 2009 Location: Portugal Posts: 215 Rep Power: 18	Hi Bin, I just finished a simulation with 1/40 ratio between sphere radius and channel height, and my Cd value deviates just 3% from Stokes law (in my previous attempts the error was higher for smaller channel height). What analytical solution you have? Regards, Jose Santos

March 30, 2009, 14:14		#43
zhoubinwx Senior Member ZHOU Bin Join Date: Mar 2009 Location: Nanjing/Torino, Nanjing/Piemente, China/Italy Posts: 164 Rep Power: 17	Hi, Santos, The expression of different analytical solutions for sphere case is in my Vista system. I will email you tonight. Please accept it from Italy Best regards, Bin

March 31, 2009, 02:54		#44
marico Member Marco Müller Join Date: Mar 2009 Location: Germany Posts: 94 Rep Power: 17	Hi FOAMers, I'm doing the same things around the cylinder. I previously ran a case with k-Epsilon around 1E+5 < Re < 1E+6 sucessfully. Now I try to do the same with kOmegaSST model, but the solution is not fine, the forceCoefficients are not steady. Can someone please help me with the boundary conditions for k and omega ?! What about zeroGradient a Inlet for such a case? Thank You Marco

March 31, 2009, 11:50		#45
lin Senior Member Hua Zen Join Date: Mar 2009 Posts: 138 Rep Power: 17	I'm not sure,but generally it seems to be a general rule to prescribe inlet values of turbulent quantites.You could guess the value or use the value from experimental results.