Drag force coefficient too low for a flow past cylinder at Re= 1e05

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October 18, 2014, 15:43
Drag force coefficient too low for a flow past cylinder at Re= 1e05
#1
Member

Join Date: Dec 2013
Location: Newcastle
Posts: 54
Rep Power: 12
Dear all,

I just start to use Star-ccm+. I try to simulate a flow past a stationary cylinder at Re=1e05. However, the result I got is quite different from the experiment. The previous experiment shows the Cd is around 1.1, my simulation result is around 0.55.

Here is the information of my cases,

Mesh:

cylinder diameter: 0.1m
flow velocity:1m/s
Re=1e05
Thickness of near wall prism layer 2e-05 (y+=1)
Aref 0.0314m/s^2 (the front area, my cylinder height is 0.314m)
timestep 0.0005s
simulation time: 10s

The flow inlet boundary is located 10D upstream from the centre of the cylinder and the flow outlet boundary is located 25D downstream from the center of the cylinder. The top and bottom boundaries are located at a distance of 10D from the center of the cylinder.

Mesh picture is in attached.

Models:
Three Dimensional
Liquid (H2O)
Segregated flow
Constant density
Turbulent
Large Eddy Simulation
Dynamic Smagorinsky Sugird Scale
Low y+ Wall Treatment

Cd properties
Coordinate System : Laboratory
Direction:[1.0,0.0,0.0]
Force Option:Pressure+Shear ( I try only Pressure but there is no different and I don't know which option should I choose)
Reference Pressure: 0Pa
Reference Density: 997.561kg/m^3
Reference Velocity: 1m/s
Reference Area:0.0314m^2
Parts： cylinder

Boundary

cylinder: no-slip wall
inlet:velocity inlet
outlet pressure outlet
front,back,top, down: symmetry

I make first several time step interaction 150, the change it to 20, make the continuity residual close to 1e-04

I try the mesh polyheral mesh with 70w cell however the Cd is 0.55 which just half of the experiment result.

Could Anyone give me some recommendations about which setting is wrong in my case?
Many thank with your kindly help.

Here is my simulation case, I am using version 9.04.011-R8

Best Regards,
Scabbard
Attached Images
 Capture.jpg (46.3 KB, 57 views) Capture1.jpg (33.5 KB, 48 views)

Last edited by Scabbard; October 22, 2014 at 18:09.

 October 22, 2014, 18:09 #2 Member   Join Date: Dec 2013 Location: Newcastle Posts: 54 Rep Power: 12 Dear all, Here is another discussion I posted about this problem. http://www.cfd-online.com/Forums/mai...tml#post515042 I try several method (URANS, LES, different mesh )about simulating this. every time I got Cd around 0.5. Could anyone help me find where is the mistake I made? I am really sick with this problem now. Many thanks, Best Regards, Scabbard

June 5, 2020, 14:44
#3
Member

Gang Wang
Join Date: Oct 2019
Location: China
Posts: 64
Rep Power: 7
Quote:
 Originally Posted by Scabbard Dear all, Here is another discussion I posted about this problem. http://www.cfd-online.com/Forums/mai...tml#post515042 I try several method (URANS, LES, different mesh )about simulating this. every time I got Cd around 0.5. Could anyone help me find where is the mistake I made? I am really sick with this problem now. Many thanks, Best Regards, Scabbard
Hi!

Did you solve this problem? I'm also troubled with this problem. I know it's quite an old post but I'm still wondering....

Could you please share the solution and thinking with me?

Best
Gang