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non uniform boundary conditions

Submitted by mariotome on January 12, 2013 - 19:30

I am trying your tool, but I am quite beginning. One key issue to me is to use boundary conditions with varying values for U, V, W and k and epsilon. Is it possible with caedium?

I am not finding the way to do that. Maybe I need to look better for other examples.

Thanks for your help.

Mario

‹ Steam release object moving upwards and flow from the left to right ›

Prescribed boundary condition values

Submitted by symscape on January 14, 2013 - 09:39.

What boundary value variation profiles are looking to impose?

Currently Caedium does not support arbitrary (e.g., file based) variations. However, there are prescribed boundary condition value profiles for rotation and an Atmospheric Boundary Layer (ABL).

If these conditions are not adequate for your needs then you can consider extending your inlet region to allow the boundary layer profile to develop.

that's my interest ABL

Submitted by mariotome1 (not verified) on January 14, 2013 - 20:55.

that's my interest ABL profiles like

U=5m.s-1(z/10m)^0.3; Z=vertical coordinate in meters:
and also for k and epsilon.
e.g. epsilon = u*^3/(0.4(z+zo))

My domain is about 100 meters high (flow around buildings in a city) and profiles for the "velocity inlet face" are varying only with height (=z).

Is possible to assign those kind of profiles with caedium? How?

Thanks again,

Mário

Caedium does support ABL

Submitted by symscape on January 15, 2013 - 11:04.

I'll assume you are familiar with the setup of a Caedium CFD simulation. If not review the tutorial "Incompressible Flow Through a Pipe into a Box"

I suggest you try a simple box first to confirm the ABL condition is producing the profiles you expect.

To use the ABL inlet boundary condition:

  • Construct a single flow volume to represent the air
  • Assign the Air substance to your volume
  • Set Substance:Air->Solver:RANS Flow->Turbulence Model = k-epsilon (or other epsilon-based model for the epsilon profile)
  • Drag and drop Conditions->Inlet onto your inlet face
  • Set Physics:Inlet->Type = ABL, and set your profile parameters as required

Tool tip descriptions will display in the lower left status bar if you select the ABL properties.

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