Convection is only computed for the region of the sample. Try to solve convection on a coarse mesh in the beginning as is set for the rest of the furnace. If necessary, refine the mesh for the region of the sample, in particular at the velocity boundaries.
The following mesh parameters produce a reliable mesh for computing convection.
Select the convective region of the sample with the left mouse button.
Select Settings > mesh.
Replace the Edge length of the region by 0.0015.
Replace the Fit slope by 0.3.
Replace the Edge length of the line by 0.01. Since no line is selected, this is taken as the default value for all lines.
Click on Apply.
Click on the Generate mesh button
.
The mesh will be recomputed. Because a mesh already existed, the system will ask you, whether you want to recompute the entire mesh or only for the selected region.
If your answer is no, the mesh will only be computed for the region of the sample. Before starting the actual computation, it is recommended to generate the whole mesh once by clicking yes.
Click on the Show/hide mesh button
.
Click on Close to close the mesh dialog.
Click on the Show/hide mesh button
to turn off the display of the mesh.
Click on the Zoom out button
to reset the furnace to its original size.
