[Zhiheng Wang]

Hi,
In my boundary condition Temperature T changes with gradient.
how can I modify if T is defined as "const volScalarField& T = thermo.T();"
in creatField.H.
I want to correct T at boundary with some function.
please provide the solution.

[anishtain4]

Are you trying to do this along with a standard solver? Or you are developing your own solver?
Sorry but your problem is not clear.

If you want to update the boundary condition based on its gradient, there are many boundary conditions available that you may choose depending on your problem such as fixedGradient and mixed

[Zhiheng Wang]

Originally Posted by anishtain4

Are you trying to do this along with a standard solver? Or you are developing your own solver?
Sorry but your problem is not clear.

If you want to update the boundary condition based on its gradient, there are many boundary conditions available that you may choose depending on your problem such as fixedGradient and mixed

I want to developed my own solver where convective-diffusive velocity depends on

dT/dy = rho*Uy*LatentHeat/kappa;

I know how to take sngrad in account to calculate dT/dy but my boundary temperature is not changing due to const volScalarField , it gives error

[anishtain4]

You can use

volScalarField& myT = const_cast<volScalarField&>(T);

to cast away the constness of the pointer. But I wouldn't suggest this.
If your only going to change the boundary condition then why are you developing a solver? And if you are developing a whole new solution that involves solver and boundary just develop them separate. I'm still not clear if the formula you mentioned is going to be used only on boundary or the whole domain, but I guess it can either be done with already existing conditions or developed separately from the solver.