The heat transfer model convergence at first, but when I increase the electric potential or calculation time, it turns do not convergence, I want to know why, wrong boundary condition, or something about mesh or solver?
Thank you all!
It might be due to a numerical instability. Check the characteristic lenghth and time scales of the problem in comprison with your mesh.
it is not so uncommon the problem you pose. Basically, You got two options in comsol: If you are solving a stationary model try with a time-dependent model instead, fixing asymptotic-to-steady conditions or/and try with a finer mesh. Let us know! Best
It is a common problem in modeling heat transfer that would be relative with numerical stability.
For heat conduction, you have to ensure that dt and dx in your solving schema fulfill von-Neumann stability criteria, i.e. dt< (k/2*rho*c)*dx^2 where k is thermal conductivity, rho is density, c is heat capacity. This issue is significantly discussed in the chapter 6 of Haberman's book "Applied Partial Differential Equation".
For heat convection, you have to ensure the dt and dx in your solving schema fulfill Courant-Levy-Friderich criteria, i.e. dt < C dx/v_max where C is Courant number and v_max is the maximum velocity magnitude across the entire domain. Generally a Courant number less than unity is basically okay for most problems, but it is still better to make some mannual tests to find a suitable Courant number.
Thank you all! you offer me so many valuable suggestions, and I will try them!
Hello, Please what is the steps for plotting the stream function in COMSOL program?
- Badges
- Science topic