[saini@]

I am performing a simulation of flow in a horizontal pipe. when I used constant properties of water it is conversing but when I use variable properties it's showing "Divergence detected in AMG solver: k"
it is because the vale of viscosity increasing 1.000e+5 in 1 or 2 cells.

I tried to start with constant properties and then variable but still showing the same problem

Ps. I am using a polinomial function for the variable properties.

thanking you

[AlexanderZ]

check you polynomial first, increase k limits -> may be it will decrease later with convergence
mesh quality could be an issue as well

best regards

[saini@]

thank you, sir,

1.JPG

I am using hex mesh, before this, I was using tetrahedral mesh but in both cases, it is increasing only in 1 or 2 cells.

One more thing: is it necessary to use the same order polynomial for all properties? because it is working when I change density and thermal conductivity but as I change viscosity with them it's not working,

[AlexanderZ]

this is your model, you can do whatever you want
if you think, that constant values are not suitable for your simulation, than you use transient properties

best regards

[saini@]

Thank you for help, I tried with different types of the mesh but when I used variable properties, always it's diverging. is it a problem of initial vale or something else? And what should I do for it? Please help!

Thank you again.

[AlexanderZ]

check properties, which you are using.
change them from constant to transient one by one -> so you can find which one leads to error

best regards

[saini@]

Thank you, sir, The problem was in viscosity function when I reduce the order of polynomial its start working

Thank a lot