Hello I am a new user to Butterfly and have done extensive research on the simulation and modelling methodology. I have been running wind simulations using the butterfly plugin. I used the outdoor airflow example script with a wind velocity of 3.1 m/s. I used Paraview to visualize the results. I encountered the following problem.
A box has formed about the size of the refinement region surrounding my building model. This result looks incorrect as wind does not flow in such a way.
I have tried running the script without a refinement region but was not able to get proper mesh for the geometry. I would appreciate any help from fellow butterfly users.
Thanks
For further investigation, I ran the simulation with the same parameters as the previous run except without any surrounding buildings to check if the wind shadow caused the box to form and increased the number of iterations. I visualized the results in paraview and extracted the following images.
Comparison of New(left) and Old(right) results.
The box error still persists proving it was not due to the wind shadow of surrounding buildings.
The jagged edges of the wall have reduced and change in Wind Velocity visualization could be due to the fact that the number of iterations were increased in the new run.
Hi @JohnBricks@sarith Butterfly is using OpenFOAM as CFD engine which need fine meshing for nice resulit As I know, refinement region will decrease the wind speed inside it. I suggest you to use XYZ grading to get a bettter blockMeshing.
Here is my butterfly result. You can refer to it.
Hi @minggangyin . Thank you for that useful tip! It worked and we were able to mesh with 2 billion cells.
I have another question if you do not mind, the streamlines that are moving at speeds which are greater than 0m/s seem to abruptly stop at some distance from the model. So, does this mean that there is an issue with the result?
I have attached the New(left) and Old(right) paraview visualizations.
