x-velocity with and without sed. species

John CFD Newb · December 15, 2014, 07:04

Hello all,
I hope my question is not something trivial, but i really can not explain it.
I have already simulated only water in a settling tank and I got good results based on some experimental data. When I introduce the different sed. species , the resulting x-velocity when the simulation reaches steady state is different than the one in clear water. Why is this happenning? Should not the x-velocity remain the same theoritically?

Thank you in advance.

JBurnham · December 15, 2014, 14:14

The x-velocity is the velocity of the mixture: sediment and water together. By adding sediment, you are increasing the mixture volume and density. So the mixture has a larger wetted area and a different density; it is not expected to have the same velocity. Does that help?

December 15, 2014, 07:04	x-velocity with and without sed. species	#1
John CFD Newb New Member John Join Date: Oct 2014 Posts: 5 Rep Power: 11	Hello all, I hope my question is not something trivial, but i really can not explain it. I have already simulated only water in a settling tank and I got good results based on some experimental data. When I introduce the different sed. species , the resulting x-velocity when the simulation reaches steady state is different than the one in clear water. Why is this happenning? Should not the x-velocity remain the same theoritically? Thank you in advance.

December 15, 2014, 14:14		#2
JBurnham Senior Member Jeff Burnham Join Date: Apr 2010 Posts: 204 Rep Power: 17	The x-velocity is the velocity of the mixture: sediment and water together. By adding sediment, you are increasing the mixture volume and density. So the mixture has a larger wetted area and a different density; it is not expected to have the same velocity. Does that help?