My problem is as follows;

Two swimming pools in a cubic shaped building with a ventilatin system. The temperature inside the pool and ambient air through the ventilation system is different. The results will be air flow pattern and moisture concentration.

I'd like to know how to model the swimming pool. Euler mixture model could be used. But how I can model the water surface of pools? Instead of using velocity inlet or mass flow rates, I'd like to use a different boundary conditions that can consider water evaporation due to temperature difference and wind.

Answer the two following questions:

What is the dimension of you moisture particles? What is the maximum concentration of those particles (volume/m3)

If both are very small, it is better to model the concentration of moisture through a User defined equation. It is faster and very efficient.

If not, then you have to use a mixture model, Euler-euler is not appropriate for your problem.

Concerning the water surface of pools, you can model it as a wall, with a non or a slip condition.

Do you also want to model vapor concentration in the air? If yes you should also model it with an ud-scalar, then you have to define a flux at the wall modeling the water interface. This flux is a function of the temperature, so you need to write an UDF.

I hope this helps.

Thank you for your suggestions.

Could you please let me know what is the relation between the temperature above the pool water surface and water evaporation? Is that also related with wind speed?

If you want to model the evaporation rate, you should find a relation (pressure/temperature/phase change)...you can find it in litterature..

Have a look on the following web site, it might help:

http://www-das.uwyo.edu/~geerts/cwx/...04/penman.html