Reply To: Simulation of a storage in a lake – Which tool should be used?

[Rob]

The appoach depends a little on what you expect to happen, and how precise an answer you want. 

Fluent would give you the heat transfer. Does the warm fluid cool, or is there a heating system? For the latter, that's steady state so a "simple" buoyancy problem. I'd be wary of modelling both warm and cold fluids simply for stability reasons. 

Mechanical would be the tool to determine the stress/strain/deformation. But... If you can assume the HTC values on the skin you could do it all in Mechanical and omit the Fluent model.