Drag coefficient of square cylinder

tonka · November 28, 2010, 15:08

I'm testing a new CFD code using the turbulent flow around a square cylinder as a validation case. Pulblished drag coefficient Cd (measured and CFD) are typically between 2.0-2.1 for Re of 20000. My initial 2D runs gave Cd of 2.8 which is significantly higher than established number. At this point I can either try finer mesh size or move to 3D which takes a lot longer. My question is, can one get the 2.0 - 2.1 drag coeff. using 2D modeling?

nidhul 07 · March 15, 2014, 12:08

yes ofcourse . i had done the simulation with Re=22000 and i obtained the value of cd=1.98
(kw sst model )

mali · April 2, 2014, 21:42

Hi All,

Thanks for posting this topic. I also got about the same value, CDmean = 2.13 and CLrms = 1.36, using 2d kw-sst model and a wall function. The number of cell along the edge is 30 x 4edges.

But when I refine the grid to 80 x 4edges and without wall function (y+ < 3), the CDmean drop to 1.57 and CLrms drop to 0.45. Any comment??

Thanks,

November 28, 2010, 15:08	Drag coefficient of square cylinder	#1
tonka New Member Join Date: Nov 2010 Posts: 4 Rep Power: 15	I'm testing a new CFD code using the turbulent flow around a square cylinder as a validation case. Pulblished drag coefficient Cd (measured and CFD) are typically between 2.0-2.1 for Re of 20000. My initial 2D runs gave Cd of 2.8 which is significantly higher than established number. At this point I can either try finer mesh size or move to 3D which takes a lot longer. My question is, can one get the 2.0 - 2.1 drag coeff. using 2D modeling?

April 2, 2014, 21:42		#3
mali Member Join Date: Mar 2009 Location: adelaide, SA, Australia Posts: 32 Rep Power: 17	Hi All, Thanks for posting this topic. I also got about the same value, CDmean = 2.13 and CLrms = 1.36, using 2d kw-sst model and a wall function. The number of cell along the edge is 30 x 4edges. But when I refine the grid to 80 x 4edges and without wall function (y+ < 3), the CDmean drop to 1.57 and CLrms drop to 0.45. Any comment?? Thanks, __________________ *mali*

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March 15, 2014, 12:08		#2
nidhul 07 New Member Join Date: Jan 2014 Posts: 1 Rep Power: 0	yes ofcourse . i had done the simulation with Re=22000 and i obtained the value of cd=1.98 (kw sst model )