# Calculation of buoyancy in a stratified water tank

I'm trying to calculate the buoyancy force in a stratified water tank. The model of my tank looks like this:

Now I'm expecting cell 5 with Temperature $T_5 = 50^\circ C$ to have an upward buoyancy force. But as my cells do not "displace" water and have changing densities above (in this case even 4 different cell-temperatures) and below them I don't know which densities to use for my calculation.

Currently I'm calculating the buoyancy force $B$ by only comparing each cell with the cell above, like shown in this equation: $$B_{Cell5} = g V_5 \left(\rho_{Cell4} - \rho_{Cell5}\right)$$ Is that correct or do I have to consider the densities of cells 1 - 4 and cell 6? Thanks in advance!

• – John Rennie Jun 21 '16 at 14:49
• Yea that's my old post. But I felt it had to many different questions and unclear formulations in it. Besides that question one has been (most probably) resolved. So I thought it might be easier to just ask one of the questions. Sorry if that was not the good way to do it. – Scotty1- Jun 21 '16 at 14:54