Rotating triangles on a water surface
Raymond Bergmann
Fluid•DTU
Department of Physics
Abstract:
We present an experimental study of polygons forming at the free surface of a water flow driven by a rotating bottom and confined to a stationary cylinder. In particular, we study the case of a triangular structure, for which we present measurements of the surface shapes, the surface flows and the process of structure formation. We show that the triangle emerges by a linear instability from a circular 'base' state.