I am modeling a closed water tank (actually a pool) at a specific water temperature and introducing a higher temperature water at the top of the tank. Over time, I would expect the inlet to have a lower density than the rest of the water body. However, even with “Compressible” switch on, the density remains constant at the value set for the material “Water” throughout the entire pool and never changes with time. The net effect is that two different temperature water areas are mixed fairly quickly.
However, if I use a multi-phase model with two different densities of water, the model behaves as exactly as expected with a distinct separation region of the two water temperatures and as time progresses, the top contains more lower density water and the bottom, less higher density water.
Does the convective heat transfer model take into account changes in density due to temperature differences? It appears that it really doesn’t although I would have expected it to. The field density plot shows up as constant over the entire volume for all time steps.
Also, with a convection model, why is the water density specified explicitly instead of calculated? Temperature should affect the density, correct?
What am I missing?