Unexpected flow pattern in Incompressible analysis around a block

I had my simulation (incompressible) set up in a usual way like projects I did half a year ago. However, I could not get a reasonable result. The airflow from a 3m/s source could get over 100m/s result somewhere in the testing zone. Obviously, the wrong result pattern is confusing.

Here is the test I did and I have had ran several times with different set up I can think about. SimScale

This is a screen shot of run 5.

In run 5 I had my input velocity speed at 3m/s but received over 40m/s around my testing object. And the flow vectors around the inlet do not point in the right direction.

I suspect my simulation run time is too short (500s), thus I extend it, and ran 6 shows the same problem and the flow pattern is incorrect according to my limited experience.

Could anybody help discover where I had incorrect setting up? Thanks million~

Hi there, thank you for using the forum!

The issue here is mesh related (23k cells are way too little here). Could you try Level 5 and a region refinement around the building? You can use this project as reference:

You can also activate the potential flow initialization, and set the end time to 1000 sec in the Simulation Control too.

Let me know how this goes :slight_smile:

Best regards,