Learning Forum

[sandeep_dattu]

Hi everyone,

I'm doing 3D steady state simulation of melting in ansys fluent using solidification module. When I monitor my residuals and temperature vs iterations, I'm getting very high fluctuations in both my residuals and temperature and the images are uploaded. I have tried mesh refinement and also with different under relaxation factors. I'm using boussinesq approximation with operating temperature of melting temperature of liquid part. I have also tried piecewise linear and also polynomial variation of density in addition to this but couldn't find solution. The geometry is like cylinders inserted in the mould of melting material with 5 walls except on the top and the cylinders are given heat flux. Anyone please help me out on this.

Thanks in advance

[Rob]

Plot some monitors of temperature, flow velocity and solid fraction. I suspect you have a transient flow. n

[sandeep_dattu]

Thankyou for the reply Mr Rob. But I have specified steady state. Is it possible to have transient flow even after specifying steady state in settings.??n

[Rob]

Steady is the equilibrium solution. If the solution is tightly linked, so solidification alters the local temperature or flow to cause melting, then there are many steady solutions: ie the result is transient. Monitors will typically give sine curve results or the like and residuals get stuck with a lot of noise: exactly what you've plotted above. n

[sandeep_dattu]

Thankyou Mr Rob. What you told makes sense. I'm not getting such fluctuations in transient. Also my solution is tightly linked as you told and hence not getting results in steady state. Thankyoun

[Rob]

Look carefully in transient, it's also possible that the solid is slowly building up so will converge to the equilibrium state more readily. n