There are two regions that is next to each other and is connected by the interface. There are mass and heat exchange between this interface (actually, this interface belongs to "interior" in fluent). I want to set a fixed gradient of species mass fraction at this interface as i want. However, it seems to me that FLUENT does not have this function for user at "boundary condition" panel. So how to solve this kind of problem in FLUENT? Thanks.

I think it's possible by defining this interface as a wall zone and by using a UDF for the mass fraction.

Good luck!!!

Ari

Hi, ari I am still confused. There are mass and heat transfer between the interface. If i change it to wall, the only choice of boundary condition at wall for gradient of species mass fraction is "zero diffusive flux" and i still can not set a fixed gradient of species mass fraction as i want. In addition, how i keep the mass and heat transfer as it does at interface ?

Before you have to define an UDF, for example with the macro DEFINE_SOURCE() (see UDF manual) and then the new option ("user defined") should be available. I'm sorry, but I have not understood.

Ari

Before you have to define an UDF, for example with the macro DEFINE_SOURCE() (see UDF manual) and then the new option ("user defined") should be available. I'm sorry, but I have not understood the last question.

Ari