| Author | Message | ||
     Richard Boonstra (rboonstra) New member Username: rboonstra Post Number: 1 Registered: 01-2006 |
I am modeling convection in a crucible of molten metal and using the "penalty" parameter to enforce continuity. The convection is not driven by buoyancy but by a gradient of surface tension on the free surface. (The surface tension varies negatively with temperature.) Gravity acts normal to the surface. When I exclude gravity I can get a credible solution. When I add a small amount of gravity (g = 0.001 m/s^2), I get a solution that clearly does not satisfy continuity (flow vectors cross a boundary). If I increase the penalty factor the solution looks better but takes a very long time to converge. Achieving a solution for g = 9.8 m/s^2 seems remote. Any thoughts? Thanks for your help. | ||
| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 530 Registered: 06-2003 |
Vectors in a vector plot represent conditions at the root of the vector. It is possible that you are seeing interior vectors that cross the boundary for graphical reasons. Try plotting the surface-normal velocity as an elevation on the boundary or a contour on the surface. Or zoom the vector plot to a very small area near the surface. Or send me the script, and I will look at it. | ||
| Richard Boonstra (rboonstra) Member Username: rboonstra Post Number: 4 Registered: 01-2006 |
Thanks. I managed to reformulate the problem in terms of stream function and vorticity, which avoids the difficulty. |