Modelling free convection using low Re k-omega

Jakob Munch

Currently, I am working with free convection (Gr=10^6-10^7) around a hot water pump, and are getting some non physical looking solutions.

I am currently using Fluent 6.

At theses Gr numbers it makes sense to compare it with a boundary layer velocity profile from a laminar solution.

The flow field becomes almost uniform in the boundary layers and the velocity seems to be to low, with exeption of the cells next to the walls. In theses cells the velocity becomes way to high.

My boundary layer grid are mayby at bit to coarse, but are ok according to most guidelines. At this point I already have +2,500,000 cells and have reached the limits for our computer.

Best regards Jakob Munch, Denmark.