Problem with results of simulation of flow past sphere at Re=250

quarkz · December 23, 2011, 17:14

Hi,

I'm trying to simulate flow past sphere at Re=250. From the literature, it seems that at this Re, the flow is no longer axial symmetrical, but a plane of symmetry still exists. Besides a non-zero drag force (cx), there is also an additional force in the non-symmetrical flow direction (cy). The force in cz is zero, since it's still symmetrical.

When I try to simulate it, I got a similar cx value, but my flow is no longer symmetrical in all direction. My cy and cz are also almost the same value.

I tried to refine my grid but there is no difference. Does anyone has experience in this before? What could have gone wrong?

kid · December 29, 2011, 03:24

Can you look into paper again, as it seems as if the object is cylinder and not a sphere? ( though the side view for both would be same)

Regards
kid

quarkz · December 30, 2011, 07:31

Thanks Kid but I think I got the ans - I need to look the diagonal y and z. from that view, it is symmetrical

December 23, 2011, 17:14	Problem with results of simulation of flow past sphere at Re=250	#1
quarkz Senior Member TWB Join Date: Mar 2009 Posts: 414 Rep Power: 19	Hi, I'm trying to simulate flow past sphere at Re=250. From the literature, it seems that at this Re, the flow is no longer axial symmetrical, but a plane of symmetry still exists. Besides a non-zero drag force (cx), there is also an additional force in the non-symmetrical flow direction (cy). The force in cz is zero, since it's still symmetrical. When I try to simulate it, I got a similar cx value, but my flow is no longer symmetrical in all direction. My cy and cz are also almost the same value. I tried to refine my grid but there is no difference. Does anyone has experience in this before? What could have gone wrong?

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December 29, 2011, 03:24	hi	#2
kid Senior Member cfdkid Join Date: Mar 2009 Posts: 133 Rep Power: 17	Can you look into paper again, as it seems as if the object is cylinder and not a sphere? ( though the side view for both would be same) Regards kid

December 30, 2011, 07:31		#3
quarkz Senior Member TWB Join Date: Mar 2009 Posts: 414 Rep Power: 19	Thanks Kid but I think I got the ans - I need to look the diagonal y and z. from that view, it is symmetrical