# Flow in a centrifugal finishing machine (OTEC) at medium Reynolds number in 3D

Computational details
Short description and remarks
Visualization

 Short description and remarks Flow at medium Reynolds number in a centrifugal finishing machine with rotating lower part. Here, the rotation speed is periodically oscillating so that prescribed boundary velocities are varying by about 50 % around the mean velocity. More details on this simulation and the industrial background can be found directly from OTEC PRAEZISIONSFINISH. This simulation here is only a pre-study for a real configuration, but it contains already some of the essential features. For instance, the purely 2D rotations of the (lower) boundary part generate convective flows in vertical direction so that a completely 3D behaviour is the result which can be demonstrated via the following MPEG movies! At the moment, the interior part/hole of the inner rotating cylinder is described via the "Fictitious Boundary Conditions". This means that the position of the actual boundary is determined via "filters" and incorporated into the iterative solvers! A more detailed description of the underlying mathematical and numerical concepts is given in Stefan Turek's CFD-book, Springer . This is one of the first 3D pages in the `Virtual Album' which has been completely created via GMV (`General Mesh Viewer'). A description of the visualization steps corresponding to each MPEG video is described here or can be downloaded here! Visualization Pressure Visualization via shaded plots with isovolumes, sliced view from the side and from the top, respectively. The periodicity of the velocity on the boundary can be detected in the pressure, as kind of periodic "waves" in vertical direction. Velocity Visualization via shaded plots of the norm of velocity (sliced view from the side). Visualization via shaded plots of the vertical velocity in z-direction (with isovolumes), negative and positive contribution (sliced view from the side). It is demonstrated the convective flow is generated which goes upwards near the outer boundary, and additionally over the interior cylinder part which is rotating, too. Visualization via shaded plots of the vertical velocity component (with isolines) on extruded cutplanes. Again, the 3D convective behaviour in vertical direction gets visible. Visualization via vector plots (vectors) to illustrate the prescribed boundary values and to show the flow field on an interior cutplane. Please send any comments and suggestions to: featflow@featflow.de