You may want to take a look at your mesh first. If you are sure about it, then decrease your momentum underrelaxation factor. Still suffering? Then, evaluate your time step size (if it is an unsteady case) according to the CFL condition. You may as well use Coupled solver. I have experienced that it is more stable in some CFD analyses. Good luck!
Inlet boundary condition I have given as velocity and outlet as zero static pressure. SO there wont be the conceppt of flow reversal.
This error comes because of divergence is detected in the residuals while iterating the equations it might be because of wrong problem formulation or it might be happened because of wrong pressure velocity coupling.If you are confident about the way you formulate the problem then simply change the solutions controls.
You may want to take a look at your mesh first. If you are sure about it, then decrease your momentum underrelaxation factor. Still suffering? Then, evaluate your time step size (if it is an unsteady case) according to the CFL condition. You may as well use Coupled solver. I have experienced that it is more stable in some CFD analyses. Good luck!
Check the link
http://www.cfd-online.com/Forums/fluent/43285-divergence-detected-amg-solver-momentum.html
hello friends,
Am working on ansys fluent based on fluid dynamics of a high speed train and am receiving a message like DIVERGENCE DETECTED IN AMG SOLVER:X MOMENTUM.
I have checked my meshing and everything looks ok. i have also reduced my URF to 0.01 but no solution. I am using inviscid.
I will appreciate any help.
If your model has an inlet and an outlet as outflow or anything other than a pressure-outlet this problem might occur. Try to change unused boundaries from "wall" to pressure-outlet or outflow and see if problem still persists. I did this and it solved my problem.
The x-momentum'' divergence message is encountered by the many users of ANSYS, which is highly related to the improper selection of Symmetric axis. So, I recommend you to check user manual carefully. Hope it may help you !!
I am trying to analyze heat flow in an annulus of hollow cylinder keeping water as a medium in the annulus.
1) tried to model in 2 D axisymmetry keeping id 30mm and od 152 mm height of cylinder as 124 mm.
the boundary condition applied are: inner dia with temp 304 K and outer dia 300 K, top and bottom surface isolated means adiabatic
2) tried keeping in 2 D planar by treating it as a square of size 124 by 124 mm.
the boundary condition applied to the four sides of this square with temp 304 K from the bottom surface and 300 K to top surface, left and right walls isolated means adiabatic.
when i use air as a medium i get some kind of solution without error but when i replace it with water, i get the error "Divergence detected in AMG for x-momentum: protective actions enabled"
can someone help me to figure out the mistake
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