This is a simple minded question - when using the INLET/VALUE statement pairs to setup an inflow boundary condition, what are the correct units? A previous discussion on this forum seemed to indicated that mass *fractions* were used but I can't find a reference to that in POLIS.

I was told PHOENICS uses CGS units which seems to indicate the units for the VALUE() statement when specifying inflowing species is grams/second/cm^2. However, in the POLIS reference for COVAL it refers to Kilograms as the units, and MKS units are also referred to in the VR lectures.

This is rather confusing and I would like to know the input units for mass inlets with the INLET/VALUE statements as well as initial conditions for species using PATCH/INIT and FIINIT statements.

Thanks, PattiMichelle

PHOENICS uses SI (MKS) units by default. The only exception is when using the PHOENICS-CHEMKIN interface, in which event CGS units should be used.

The default PHOENICS practice is that chemical species are always solved in terms of mass fractions.