Learning Forum

[AISWARYA K P]

For my model, the height of the building is 300m and the scaled model for fluent simulation is 1m. The velocity is 23m/s and I need to get a yplus of 1. This is my settings. But after simulation my yplus is getting as 150. Can anyone please help me  in solving this.?

[NickFL]

Look at how yplus is defined. What you are going to need to do is go back into meshing and refine the mesh where the values are 150. This iterative approach is typical as we do not know the solution beforehand and must guess an appropriate mesh size. Then we go back and refine the mesh after examining the results.

[AISWARYA K P]

Thank you so much. I will try the same.

[Sascha Gross-Hardt]

Use inflation layers (prism layers) to provide adequate wall resolution if not already done. Particularly focus on the first element offset (distance to the wall) as it dominates the Y+ value and try to have a smooth transition from the inflation layers to the rest of your mesh.

[Rob]

As a comment. If you calculate the cell height to get y+ of 1, what is that cell height relative to the surface distortions (trees, cars, curbs, bushes etc)?  The other comments answer your immediate question, but you might want to consider the rest of the factors before going too much further.