Reply To: unrealistic velocity at the entrance of the pipe (orifice)

[abhishek.srivastava2]

The BC conditions need to be maintained. It's a fan the end of pipe which sucks the air into pipe throiugh the orifice. So, i can only control the fan speed (outlet pressure). Previously i had the environent box in the shape of a big cylinder around the orifice to get air from the two side and front of the orifice, and that design worked perfectly but i was getting an error of more than 10% in required velcocity. So, i changed the cylinder box design and extended it more towards the side wall of the pipe to have more air into the pipe (and more close to real scenario) but seems this design is causing sudden fluctuations and solver is not able to capture the entrance velocity correctly. I'll try to refine the mesh little bitmore to see if it improves anything.