Help me please

Lubomir · October 29, 2011, 13:25

Hi Guys.

I have an unsolvable problem. I am beginner in CFD.
I would like to model Karman vortex trail - school experiment.

Real experiment: Pipe is placed in center of river. Behind the pipe are generated Karman vortexes. I know the velicity inlet. That´s all.

The problem: I have mesh(Gambit) of this problem, 2D solution. What are the boundary types for outlet and for two side edges?

I tried calculation but after 12000 iterations were no convergence - still oscilated.
I am not sure if I set all the parameters right.

Can You help me? Please give me advise what,where and how I must set

Thanks.

Laci · October 30, 2011, 15:25

Boundary conditions for outlet: outflow or pressure-outlet (with the proper pressure value)
The walls should be simply wall

Since the simulation of Kármán vortexes is transient, you should go for time-dependent simulation. Did you do that? From the oscillating residuals I guess you didn't.

October 29, 2011, 13:25	Help me please	#1
Lubomir New Member Lubomir Join Date: Oct 2011 Posts: 1 Rep Power: 0	Hi Guys. I have an unsolvable problem. I am beginner in CFD. I would like to model Karman vortex trail - school experiment. Real experiment: Pipe is placed in center of river. Behind the pipe are generated Karman vortexes. I know the velicity inlet. That´s all. The problem: I have mesh(Gambit) of this problem, 2D solution. What are the boundary types for outlet and for two side edges? I tried calculation but after 12000 iterations were no convergence - still oscilated. I am not sure if I set all the parameters right. Can You help me? Please give me advise what,where and how I must set Thanks.

October 30, 2011, 15:25		#2
Laci Member anonym Join Date: Mar 2009 Posts: 65 Rep Power: 17	Boundary conditions for outlet: outflow or pressure-outlet (with the proper pressure value) The walls should be simply wall Since the simulation of Kármán vortexes is transient, you should go for time-dependent simulation. Did you do that? From the oscillating residuals I guess you didn't.