Discussion Forum

We notice two peculiarities when studying your Schematic pump tutorials in Chemical Engineering module. Note that this is NOT our model or solution, but rather your provided tutorial:

1. This flow looks like it is pulsatile, even after the solution should have come to steady state. Near the blade tips, the fluid speed should be nearly the blade tip speed, but instead is pulses throughout the solution. Can you explain this?

2. Although the outer boundary of the inner (rotating) domain is paired to the inner cylindrical surface of the outer (non-rotating) mesh, there is not continuity of velocity. At several blade positions, the fluid streamlines are moving radially outward within the rotating impeller, but streamlines within the stationary mesh are nearly circumferential. This not only represents a non-physical discontinuity of flow, but also shows that mass is not being conserved within the inner rotating region because flow is everywhere moving out through the sliding interface even through there is no source.