Gradient Adaption with dynamic option

joshi20huregina · May 19, 2012, 16:56

Hi everyone

I am simulating a mutliphase flow with VOF method and surface tension effect. I am trying to use the gradient adaption with dyamic option turned on in Fluent to improve my solutions without having to make a finer mesh in the entire domain. The gradient adaption is based of the gradients of phases. However, the solution resulting from the use of gradient adaption is worse than without it. This isn't suppose to happen right? Can someone please help me?? Thank you very much.

ndabir · July 16, 2012, 14:11

using the adaption should improve your results but you should have sufficient number of mesh in the interface of two phases before using adaption.
by the way, have you solved your problem? I am simulating air bubble collapse in water and I have divergence problems. do you think using mesh adaption is necessary? I am not using it right now.

joshi20h · September 26, 2012, 13:45

Hey, I didn't use any mesh adaption and I got my simulation working. What kind of divergence issue are you having?

ndabir · September 26, 2012, 14:01

sometimes in my simulation, especially at beginning I saw that pressure values drop to 1 Pascal in some points in domain especially near bubble interface. did you solve any bubble simulation? did you encounter this problem at all? If you didn't use grid adaption, then how fine was your mesh?

joshi20h · September 26, 2012, 14:23

I am simulating horizontal bubble flow in a tube. I made my mesh finer near the wall but didn't use any adaption.

May 19, 2012, 16:56	Gradient Adaption with dynamic option	#1
joshi20huregina New Member Join Date: Apr 2012 Posts: 2 Rep Power: 0	Hi everyone I am simulating a mutliphase flow with VOF method and surface tension effect. I am trying to use the gradient adaption with dyamic option turned on in Fluent to improve my solutions without having to make a finer mesh in the entire domain. The gradient adaption is based of the gradients of phases. However, the solution resulting from the use of gradient adaption is worse than without it. This isn't suppose to happen right? Can someone please help me?? Thank you very much.

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July 16, 2012, 14:11		#2
ndabir Senior Member navid Join Date: Jan 2010 Posts: 110 Rep Power: 16	using the adaption should improve your results but you should have sufficient number of mesh in the interface of two phases before using adaption. by the way, have you solved your problem? I am simulating air bubble collapse in water and I have divergence problems. do you think using mesh adaption is necessary? I am not using it right now.

September 26, 2012, 13:45		#3
joshi20h New Member Harsh Join Date: Dec 2010 Posts: 3 Rep Power: 15	Hey, I didn't use any mesh adaption and I got my simulation working. What kind of divergence issue are you having?

September 26, 2012, 14:01		#4
ndabir Senior Member navid Join Date: Jan 2010 Posts: 110 Rep Power: 16	sometimes in my simulation, especially at beginning I saw that pressure values drop to 1 Pascal in some points in domain especially near bubble interface. did you solve any bubble simulation? did you encounter this problem at all? If you didn't use grid adaption, then how fine was your mesh?

September 26, 2012, 14:23		#5
joshi20h New Member Harsh Join Date: Dec 2010 Posts: 3 Rep Power: 15	I am simulating horizontal bubble flow in a tube. I made my mesh finer near the wall but didn't use any adaption.