[ghorrocks]

my length scale is 50 mm!

That may well be quite large, but of course a bit meaningless without the rest of the bits to make up relevant non-dimensional number. Do you know the Re, We or any other relevant non-dimensional number for your flow?

Why do you think surface tension is important? It usually is not significant for large length scales.

If you want to make surface tension a function of temperature then obviously you need to model the energy equation. This will add significant complexity and instability to the model, only do this if its contribution is significant.

I recommend you start with constant surface tension (and isothermal) before tackling the more difficult varying temperature/surface tension simulation.

The reference in the documentation describes how the compressive discretisation scheme find the free surface. Also I think there a description of the surface tension approach in the documentation.

[fab]

hi are you sure that i need the energy equation? it is q=n*delta(h)?
i have a laminar flow so i think it is RE as non-dimension number.
how did the solver know that i actually declared the surface tension by the expressions?
the surface tension-curve as function of the temperature is that what i have to implement!so it´s very important to me to know how the surface tension is changing during the flow.
i have first of all a water film on a platt .
this platt has 2 different temperatures(2 bottoms),my flow is laminar.
later i will modelling a polymersolution!

[ghorrocks]

You don't know what the energy equation is, you don't know what the Re number is.... Sounds like you need to learn some basic fluid mechanics. I would forget about modelling surface tension and polymerisation until you know the basics.

[bha2l]

dear all,, what do you think,,

i ran free surface flow on ship at 7 knot and 9 knot,,
and the result of force x on ship on 7 knot in negative but on 9 knot is positive.. which is true..??

please answer,, and thanks before..

[ghorrocks]

Probably neither.

Please do not hijack threads. Start a new thread for a new question.