[t4leung]

I want to add a mass source term for the VOF model via a UDF but I am confused how this source term is used. I would like to have this source term representing the diffusion of the liquid volume fraction so I only want the source term to appear in the VOF eqn. From the manual, it appears that the only way to have a source term for the VOF eqn is through mass transfer and I am using the DEFINE_LINEARIZED_MASS_TRANSFER UDF.

However, in the section of the manual describing UDF mass transfer, it states:

ANSYS Fluent will automatically add the source contribution
to all relevant momentum and scalar equations

I am confused about where source term is being used. Is there any way to have a source term for only the VOF eqn?

[t4leung]

In the theory manual, I found that when using the mixture model, there is an option for including the turbulent dispersion force in the momentum equation (17.5.9.1.4. Diffusion in VOF Model). This is exactly the term I want to use but I want to have the term in the transport equation for the volume fraction (17.5.4.1.1. Conservation of Mass). Is there any way of doing this?

[Ahmed Alkaisi]

I don't think you need to use a udf in your case as the source term is already included in vof model

[t4leung]

Originally Posted by Ahmed Alkaisi

I don't think you need to use a udf in your case as the source term is already included in vof model

I want to include a turbulent diffusion term in the VOF equation and that is why I am using the DEFINE_LINEARIZED_MASS_TRANSFER UDF to define my diffusion term. Is there a better way to do this?