Experimental investigations of the unsteady rotating flow field in a cylindrical vessel

Simulation investigations of the effects of whirlpool dimensional ratios on the state of secondary whirls

“…The friction between the fluid and the walls and the bottom of a vessel slows down this rotation and produces the secondary whirls which cause the sediment in the shape of a cone to be collected on the bottom (Denk & Dü rholt, 1991;Kunze, 1998). This curious phenomenon of the sediment concentration in the middle of a vessel despite the centrifugal-force action was called as the ''cup-of-tea-effect" (Einstein, 1926).…”

Morphodynamics of a sediment bed in a fluid-filled cylinder during spin-down: An experimental study

“…However, we did observe the side walls to have an impact in the generation of turbulence and the suspension of sediment. This is due to the no-slip condition at the side wall, where a differential rotation is induced, leading to centrifugal forces that cause instabilities in the flow [37][38][39][40][41][42].…”

“…To determine the cause of the particle suspension, a vertical laser sheet was used to illuminate the tank from the side and tracer particles were added to the fluid. This allowed us to observe the generation of turbulence at the side wall caused by centrifugal instabilities originating from the differential rotation due to the no-slip condition [37][38][39][40][41][42][43]. The turbulence is then advected toward the interior of the cylinder due to the secondary motion, causing particle suspension.…”

Secondary flows occurring in a whirlpool separator – A study of phenomena – observation, simulation and measurements

“…From the technological and processing standpoint, the most impactful secondary flow is the rotational flow near the separator bottom in the Ekman boundary layer (Denk and Dürholt, 1991). This flow causes the separated sediment to form a cone.…”

“…A secondary flow forms itself in the so-called Ekman boundary layer inside the separator (Denk and Dürholt, 1991). Due to sedimentation, along with an aggregate of secondary flows caused by rotational flow, the separated hot trub forms a cone in the centre of the tank.…”