Greetings,
There is a fai amount of information on the fluidic force solver here: viewtopic.php?f=8&t=480 which has assisted me to get this solver working nicely. However, I do have one question: the solver adds an extra four columns (in 3D) to the output (.ep file) following the velocity&pressure which represents ''flow.solution.loads.1" to ''flow.solution.loads.4". I presume that the components 1,2,3 are the fluidic force along x,y,z, but what is the 4th component?
John
Fluidic Force solver output
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raback
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Re: Fluidic Force solver output
Hi Captain
There are two approaches: the separate fluidic force routine does not create these extra variables. Its the other alternative (more accurate one) where you compute the residuals of the finite element matrix (using keyword "Calculate Loads") and then sum up these in SaveScalars.
The interpretation of the "Varname Loads" depends on the type of equation. In monolithic Navier-Stokes (in 3D) the first three equations are related to equation of momentum and the 4th one to the equation of continuity. So the components 1,2,3 tell the equivalent nodal forces needed to create the force field and component 4 is a measure on how well the continuity equation was satisfied. For incompressible it should be zero but in numerics life is never quite perfect...
-Peter
There are two approaches: the separate fluidic force routine does not create these extra variables. Its the other alternative (more accurate one) where you compute the residuals of the finite element matrix (using keyword "Calculate Loads") and then sum up these in SaveScalars.
The interpretation of the "Varname Loads" depends on the type of equation. In monolithic Navier-Stokes (in 3D) the first three equations are related to equation of momentum and the 4th one to the equation of continuity. So the components 1,2,3 tell the equivalent nodal forces needed to create the force field and component 4 is a measure on how well the continuity equation was satisfied. For incompressible it should be zero but in numerics life is never quite perfect...
-Peter
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Captain Slow
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Re: Fluidic Force solver output
Thankyou Peter, That makes sense.
I am using the ''calculate loads'' and incompressible Navier-Stokes equation, which explains why the 4th component (continuity) is about 10 orders of magnitude smaller than the other three components.
I am using the ''calculate loads'' and incompressible Navier-Stokes equation, which explains why the 4th component (continuity) is about 10 orders of magnitude smaller than the other three components.