I want to calculate the 2D pipe flow with sharp edged contraction pipe (below figure). The fluid is water, the model is steady state k-epsilon. The boundary condition is velocity inlet (8.47ft/s = 2.58m/s), and pressure outlet (0 psi = 0 Pa). Friction is not take into account on the wall.
The result shows negative pressure at the sharp edged of the contraction. Would you tell me why the negative pressure occurs in this calculation?
I think it's because I don't take cavitation into account at the moment, do you think this is correct? Mesh size might be an issue, but when I used more fine mesh, the result didn't change much. Is there any possibility that mesh is too fine like Courant number in transient calculation?