Laminar Flow past a Rotating Sphere in the Transverse Direction
Abstract
Laminar flow past a rotating sphere is numerically investigated using an immersed boundary method, in order to understand the effect of the transverse rotation on the flow characteristics behind the sphere. Numerical simulations are performed at Re=100, 250 and 300 in the range of 0 ≤ ω^* ≤ 1, where ω^* is the non-dimensional rotating speed of the sphere. Without rotation, the flow past a sphere experiences steady axisymmetry, steady planar-symmetry, and unsteady planar-symmetry, respectively, at Re=100, 250 and 300. With rotation, however, the flow becomes planar-symmetric for all the cases investigated, and the symmetry plane is orthogonal to the rotating direction. Also, the rotation significantly modifies the vortical structures behind the sphere, especially the characteristics of vortex shedding at Re=300. Vortex shedding occurs at low values of ω^*, but it is completely suppressed at ω^*=0.4 and 0.6. Interestingly, at ω^*=1, unsteady vortices are newly generated in the wake due to the shear layer instability.
- Publication:
-
APS Division of Fluid Dynamics Meeting Abstracts
- Pub Date:
- November 2003
- Bibcode:
- 2003APS..DFD.JM007K