Structure of a flow over a rotating disk

Computational fluid dynamics

The structure of a rotating flow is studied by Reynolds-averaged Navier-Stokes (RANS) numerical simulation. The fluid is contained in a cylindrical tank with fixed vertical sidewall. The flow is driven by the rotation of the bottom plate. The free surface shape is calculated by the level set method, and this study is restricted to the case where the free surface is plane. During simulations, the fluid taken into account is water. The Reynolds number and the aspect ratio of the flow are the varying parameters. The values of The Reynolds number used in the simulations are , , and , for the aspect ratio, they are 0.66, 1 and 1.33. Velocity fields variations are represented along three different radial line segments. One at the bottom of the cylinder, one at the half of the initial fluid height, and the last at the free surface. The velocity magnitude increases with time and when Reynolds number grows. Radial and azimuthal velocity components decrease with growing aspect ratio, and vertical velocity keeps the same scale. For every value of the parameters, the motion direction is described as followed: at the rotating bottom, the fluid goes from the center to the sidewall, near which it is upward. At the free surface and at half of its height, the fluid is tending to move toward the center. And at a certain distance from the fixed sidewall, the fluid motion is downward. This flow structure is consistent with the structure found in experimental studies reported in Bergmann et al and Jansson.

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.