[achesoch]

Hi all,


I am using the swirlFlowRateInletVelocity boundary condition in OpenFoam 2106 and can't find the definition or the units of the flow rate.


1. Is it a volumetric or a mass flow rate? What are the units?
2. I am fairly new to OpenFOAM, so I might be looking for the answers in the wrong place. I have been checking here: https://www.openfoam.com/documentati...b37c94efe9406e

(granted this is for OpenFOAM 2012). Is there an obvious place to look for specifics of particular boundary conditions or solvers so I don't need to post on the forum next time?


Cheers,
Chris

[olesen]

Seems pretty clear from the documentation you cited. However it is in the summary (not sure where you were looking).

This boundary condition provides a volumetric- OR mass-flow normal vector boundary condition by its magnitude as an integral over its area with a swirl component determined by the angular speed, given in revolutions per minute (RPM)

The basis of the patch (volumetric or mass) is determined by the dimensions of the flux, phi. The current density is used to correct the velocity when applying the mass basis.

So its meaning will depend on if you have a compressible or incompressible solver. Units will be something like m3/s or kg/s. If you have something like kg/h etc, just use the #eval for unit conversion.

[Stan Zhou]

Originally Posted by olesen

Seems pretty clear from the documentation you cited. However it is in the summary (not sure where you were looking).


So its meaning will depend on if you have a compressible or incompressible solver. Units will be something like m3/s or kg/s. If you have something like kg/h etc, just use the #eval for unit conversion.

Hi Olesen,
If I understand correctly, 'flowRateInletVelocity' defines the velocity on the boundary according to the volumetric rate we set. I wonder if there is a BC that do the opposite thing, i.e., adding more water into the fluid domain due to the velocity on the boundary.

I'm currently doing FSI coupling adopting our in-house solver (solid part) and OpenFOAM (fluid part). However, there is a question that's been bothering me:

The case I want to simulate includes a porous media baffle, with water on the left side and no water on the right. I want to simulate the process that water on the left flows into the porous media and then flows into the right side. At present, I've got the displacement and the seepage velocity (calculated in solid solver) on the interface and passed to the boundary in OpenFOAM. How could I add the additional water due to the seepage velocity on the interface? (I guess it is similar to the process of making waves since there is more water due to the velocity on the wave generation boundary. However, I don't know the specific practice, could you please share some of your experience if you don't mind.)

Best,
Haoran

[achesoch]

Originally Posted by olesen

Seems pretty clear from the documentation you cited. However it is in the summary (not sure where you were looking).


So its meaning will depend on if you have a compressible or incompressible solver. Units will be something like m3/s or kg/s. If you have something like kg/h etc, just use the #eval for unit conversion.

Thanks olesen. I'll take a more thorough look through next time. The units you stated are both SI units, which I believe is OpenFOAM's default. So for instance, if using an incompressible solver with


flowRate constant 0.1;


and I don't explicitly define the phi dictionary value, I can expect that to correspond to a volumetric flow of 0.1m^3/s?