Discussion Forum

I'm solving for lid driven cavity with stratified flow.

My error message looks:
Undefined value found.
- Detail: Undefined value found in the equation residual vector.
There are 3 degrees of freedom giving NaN/Inf in the vector for the variable comp1.T.
at coordinates: (0.080597,0.2), (0.0835821,0.2), (0.0820896,0.202422), .

Thus the error would belong to the heat transfer domain. As I understand, residual vector is the vector that is formed to solve my equation, which in this case would be the temperature equation. It would consist of my thermal properties, Temperature and velocity as a variable along with boundary conditions. But I’m unable to figure what is actually missing.

According to manual I followed “Check for undefined numerical values after each operation” in the assembly settings. After that it display this error :

Function evaluation returns undefined numerical value.
- Function: ^2
- Expression: (comp1.spf.xi_m*comp1.spf.res_v)^2
Failed to evaluate variable.
- Variable: comp1.spf.vhNS_lin
Failed to evaluate expression.
- Expression: nojac((1.4142135623730951^(1-shapeorder(comp1.u)))*max(comp1.spf.vhNS_lin-comp1.spf.vhNS_quad,0))
Failed to evaluate variable.
- Variable: comp1.spf.vhNS
Failed to evaluate temporary symbolic derivative variable.
- Variable: comp1.spf.crosswindns@VDN${test@85}
Failed to evaluate expression.
- Expression: d((comp1.spf.crosswindns)*(dvol),{test@85})
Failed to evaluate Jacobian of expression.
- Expression: (comp1.spf.crosswindns)*(dvol)

But here it seems that it is referring to components of velocities. My guess would be that it is unable to resolve velocities at the boundary or getting division by zero there.. I’m lost on how to fix this.

I don't think it is due boundary conditions or material properties are the culprits, due to fact that there are 200 iterations. Although the error plot looks really bad i.e no convergence is achieved. My initial guess is good enough since it gives an error of magnitude ~ 10^0 .

Kindly help!!


Regards
Parth Swaroop