Interior CFD influence by exterior pressure coefficients

Grasshopper Eddy3D
3

Hi @julioamodia89 I have done this before using SimScale. Honestly, it’s one of the coolest things I have done. My workflow was something like this:

  1. Upload a microclimate like geometry, site, contextual buildings and topology if necessary.
  2. Run an external simulation in the multi-directional PWC analysis. I assume the pressure at each opening to be uniform, so I read the pressure at the centre of each opening.
  3. Convert all the pressures from all openings tp pressure coefficients. Usually, I have a row for each opening and a column for each direction, as a table.
  4. Import a geometry representing an inside space (room, floor etc), with clear surfaces for openings. These will be used as the boundary conditions. If you want to include openings and resistances from the window geometry, I include a volume to apply what we call a porous media. You can define it indirectly using the estimated discharge coefficient.
  5. For each scenario you wish to simulate, create a new simulation (CHTv2), defining the correct pressure values at the opening boundaries, I.e. you want to simulate an indoor space under natural ventilation with 15 degrees ambient temperature and wind at 5m/s from the southwesterly wind direction? Use the pressure values back-calculated from the pressure coefficient in your table to define it.
  6. Observe the flow fields inside the building from the results.

This does assume a few things. For example, the openings are small, and flow through the building is not that high due to internal resistances. If this was an ample open space, for example, a rooftop garden with a cover, then a different approach should be taken.

Also, if you wanted to be fancy, you could use the API to automate a lot of this or even write something natively as grasshopper components.

If you want to see our example on this its here for the indoor study or here for the external study (Login required, you should be able to sign up to a non-commercial account and get access).

I hope this helps! I would also be interested to know your solution if you already managed it.

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