Constant mass flow rate to periodic boundaries

Altair Forum User

Hello, I'm a new user of Acusolve and have an admittedly simple question. How would I go about setting periodic boundary conditions with a constant mass flow rate (so a pressure gradient is applied between the boundaries)? For example if I want to model a turbulent channel flow - in Ansys Fluent I could apply a constant pressure gradient or a constant mass flow rate, in OpenFOAM I could apply a pressure gradient or a mean flow velocity. How would I do this in Acusolve? I've gone through the tutorials and while I've seen the periodic boundary condition addressed (heat convection), there was no flow through the boundaries that I saw in the tutorial.

 

While I am here, I have another unrelated question - what does the 'Speed' setting in the AcuProbe preferences do? I'd like to increase the refresh rate of the residual monitoring plots but cannot find a description of what the 'Speed' parameter does. Thank you!

 

acupro

First, I'll address the periodics question.  Let's assume you have boundary surfaces Inlet and Outlet.  For Inlet, you would use the standard Simple BC type = inflow, and the type of inflow you would prefer to set the flow (average velocity, mass flux - really mass flow rate, etc).  For Outlet you would use the standard Simple BC type = outflow and set the outflow pressure as normal, with the default 0.0 being fine for materials not dependent on absolute pressure.  You would have periodics set between Inlet and Outlet.  Rather than simply type = periodic (Periodic Boundary Condition checked in AcuConsole, where all variables are periodic across the pair - so un-check that) you would go into the individual Periodic BCs by selecting BC* from the left-hand column.  Then Velocity, Eddy Viscosity, etc, would be Type = Periodic, and Pressure would be Type = Single Unknown Offset.  Through the simulation, based on the flow rate and the wall effects, AcuSolve would determine the pressure drop through that periodic section of pipe or channel.

 

The auto refresh on Linux seems to work very well.  If you're using AcuProbe on Windows, the auto refresh seems more tied to whenever nodal output is written.  Which OS are you using?