When to use mass-weighted average quantity

roytorc

Could anyone let me know when to use a mass-weighted average. I'm calculating average value of scalar dissipation rate. Is it suitable?

Rob

We use mass and area weighted depending on what's needed.

For an outlet temperature (flow boundary) I'd use mass weighted. On a wall surface for temperature I'd use area weighted.

Abubakar

Hi Rob,

Can't we use in a reverse way?

Thank you,

Abu Bakar khan

Rob

Please explain, I'm not sure what you mean.

Abubakar

I mean to say that is it ok if I am using an area-weighted average for flow boundary and the mass-weighted average for wall surface

Rob

You can use those. However, how will area average account for a small region that's going very quickly when checking the mean temperature or species passing though a plane?