flow over sphere

June 1, 2006, 12:34

hi i am trying to bench mark flow over spher problem with experimental results. The drag coefficent what i am getting with cfd is not matching with experimental. Any boby can guess. the flow field is steady, 3d, Laminar and Reynold no is 100. Thanks in advance.

kr63 · January 30, 2010, 11:50

Hi
you should check where the transition and separation is taking place in both casses.

DoHander · January 30, 2010, 13:04

On the same mesh do a turbulent simulation and check your y+ if this is larger then 1, the n you are not properly solve the boundary layer region.

You can create your mesh in order to have a y+<1 and then do again the laminar calculation - also try steady vs. unsteady. You can find here on cfd-online a good y+ estimator.

Do

June 1, 2006, 12:34	flow over sphere	#1
senthil Guest Posts: n/a	hi i am trying to bench mark flow over spher problem with experimental results. The drag coefficent what i am getting with cfd is not matching with experimental. Any boby can guess. the flow field is steady, 3d, Laminar and Reynold no is 100. Thanks in advance.

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January 30, 2010, 11:50		#2
kr63 New Member khurram Join Date: Jan 2010 Posts: 8 Rep Power: 16	Hi you should check where the transition and separation is taking place in both casses.

January 30, 2010, 13:04		#3
DoHander Senior Member Join Date: Nov 2009 Posts: 411 Rep Power: 19	On the same mesh do a turbulent simulation and check your y+ if this is larger then 1, the n you are not properly solve the boundary layer region. You can create your mesh in order to have a y+<1 and then do again the laminar calculation - also try steady vs. unsteady. You can find here on cfd-online a good y+ estimator. Do