I am using a tube model with an orifice in the middle for jet flow study. My inlet bounary data is input from a table with both positive and negative velocities in only W direction. It is a trasient model.

My problem is after I run it and load the data at the boundary position, I find that there are velocities in three directions. Although you can see there are positive and negative velocities from the picture, the velocity scale ranges from 0 to maximum velocity. My question is what these velocities are. Are they still the boundary condition as i input fromt the table? If so, why velocity scale ranges from 0 to maximum velocity and I get velocities in three directions?

Thank you very much in advance.

Hi

If your duct is quiete diverging then just near to boundary you may see the velocity flowing outwards in other two directions because velocities are caculated in the all the cells including the cells where boundaries are defined. Infact bounday conditions internally is applied using ghost cells.

Regards