Pressure Based Solver, Transient flow
 

hi guys,

I have a model with 2 inlets, both feeding in different species, one with a higher density that the other, and one of the inlets has a transient velocity profile in the form of a cos wave.

The issue I have is understanding how the solver works. I am using a pressure based solveras it is suitable for 'low speed incompressible flows' suitable for my case, and solves a pressure correction equation derived from the continuity and momentum equations in order to solve the velocity field of the model by resolving the pressure correction equation, in order to satisfy mass continuity.

However, how can mass continuity be satisfied if I am using 2 different species, one with a higher density than the other? surely over time the mass is changing in different cells as fluid of the higher density flows into cells, resulting in high mass fractions of the heavier fluid?

Thanks!

PS this is a 2D simulation, using k-epsilon