Can mass inflow boundary conditions specify a constant mass flow rather than a constant volumetric flow? The documentation says the mi boundary type requires a velocity, which may not result in a constant mass flow due to an unknown pressure at the boundary.
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According to the documentation, the mi boundary type also requires a density. To me it seems that the mass flow at the BC is constant in case the velocity and density on the BC are fixed (as required). I think the pressure in the boundary cells will be calculated by the solver based on all the BCs.
per discussion w/ @jmusser, massflow is a valid option for fluids on mi and eb BCs. I’ve added to the docs. I also added volflow to the mi options which got overlooked.
to @stephan.sneijders comment, density is required for the incompressible constraint, with or without density advection. but it may not be required for reacting flows (or if it is, it might be ignored) and computed from temperature and species compositions, which are required.
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You are correct @wfullmer.
Fluid density is required for mass inflow (mi), pressure inflow (pi), and embedded boundary (eb) conditions that involve flow (flow-through-eb) when using the incompressible constraint. Conversely, if you are using an ideal-gas constraint, an error will be thrown if density is provided, as it will be computed from the required temperature, mixture composition, and thermodynamic pressure. Note that the code uses thermodynamic pressure to evaluate the boundary pressure, not the hydrodynamic pressure.
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