Dear Arash, For a subsonic outflow there is one incoming characteristic wave that needs to be computed somehow. So far I have been using the PressureOutflowNonReflectiveBC setting the farfield static pressure. I have not tried personally yet, but another option would be to try the RiemannInvariantBC. Another alternative is to add a sponge layer at the outflow. I hope this helps. Cheers, Giacomo On Thu, Jan 3, 2019 at 9:49 AM Arash Nouri <nouri.aarash@gmail.com> wrote:
Hi all,
Happy new year!
I need a kind of zero gradient boundary condition (BC) for the compressible flow solver. As Neumann BC is not implemented for “LDGNS,” I tried using ExtrapOrder0 BC, but I got oscillations on this boundary.
In my 2D simulation I have one Dirichlet and one ExtrapOrder0 BCs as the input and output of my domain and two Symmetry BCs on the top and bottom. The Mach number is very small (~0.001). Is this combination OK for the compressible flow solver? Do you suggest any other option instead of ExtrapOrder0 or Dirichlet BCs?
Thanks in advance,
Arash
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Arash G. Nouri
Research Scientist
1127 Benedum Hall
Mechanical Engineering and Materials Science
University of Pittsburgh
E-mail: arash.nouri@pitt.edu <arn36@pitt.edu>
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