[siri]

Hello friends,

I am encountering either of two errors (given below) when running DPM in Fluent for a turbulent, incompressible, rotating internal flow (like flow inside an annular cylinder).

# Divergence detected in AMG solver: w-swirl -> Increasing relaxation sweeps!
# Divergence detected in AMG solver: k -> Increasing relaxation sweeps!

I am using 2D axisymmetric with swirl option here. Before DPM simulation, I first solved for the flow itself using pressure based solver and obtained a converged solution.

The errors came up immediately after solver restarts from that converged solution. I don't get what they meant. Is it that the k & swirl residuals are too small now as flow has converged and by activating dpm, they will increase backwards. Is that not permitted to do?

Can anyone please explain me what the solver is trying to imply here?

[siri]

Originally Posted by siri

Hello friends,

I am encountering either of two errors (given below) when running DPM in Fluent for a turbulent, incompressible, rotating internal flow (like flow inside an annular cylinder).

# Divergence detected in AMG solver: w-swirl -> Increasing relaxation sweeps!
# Divergence detected in AMG solver: k -> Increasing relaxation sweeps!

I am using 2D axisymmetric with swirl option here. Before DPM simulation, I first solved for the flow itself using pressure based solver and obtained a converged solution.

The errors came up immediately after solver restarts from that converged solution. I don't get what they meant. Is it that the k & swirl residuals are too small now as flow has converged and by activating dpm, they will increase backwards. Is that not permitted to do?

Can anyone please explain me what the solver is trying to imply here?

Can anyone respond to this please. guys.... where are you

[Laurence Wallian]

perhaps you can try to reduce some under-relaxation factors...

[siri]

thanks laurence, for stopping by. i did try that ... it doesn't seem to matter but.

[Ganesh.aero]

Hi Siri, am trying to simulate a atomisation phenomenon through a pressure swirl atomiser, for the 2D geometry i have used 2d-axisymmetric swirl, have given mass flow inlet at the inlet boundary. have mentioned radial & tangential vectors, but am getting the same error- "Divergence detected in amg solver: w-swirl"

btw am using VOF method, its an unsteady laminar flow.

have you figured out a solution for w-swirl issue? if so, help me out

[Laurence Wallian]

hello,

I'm sorry but I have'nt used Fluent for a long time now, so I can't help you !

good luck for finding a solution to your problem

[Arjun_kalkur]

Hey!
While simulating flow over an airfoil (2D) I found that meshing by projecting line bodies over the airfoil leads to divergence and turbulence viscosity limited error, but if I mesh the same domain without extrapolating the line body till the inlet, outlet and the farfield, I don't get any error and the solution converges well! Any clue where I was going wrong ?
Thanks in advance

[Farhan-07]

HI,
I got same result. I am trying to do heat transfer simulation for spiral tube, tube diameter 25mm and inner diameter 22mm, outer dia of spiral is 1032mm, no of turns 22, using water HTF and heat flux is applied on top surface. BCs include inlet temp 300K, natural convection coefficient is set to 15 for bottom and side walls. But the simulation's result shows AMG solver divergence error. What should i do to resolve this error? Please help me out to solve this problem. Thanks

[uselokar]

Hi,
i am simulating a lithium ion battery using MSMD battery module in ansys fluent and got the same error . How we can resolve it.