Specific effects in liquids subject to rotational motion [articol]

Abstract

Rotational motion in ring-shaped spaces delimited by concentric cylinders is specific to rotational viscometers and consists of the relative flow of the liquid layers with velocities varying between the maximum value which correspond to the layer placed near the rotating cylinder and the minimum value when the layer is in contact with the fixed cylinder.Taylor hydrodynamic number (Ta), which depends on the ring-shaped space properties, revolution and kinematic viscosity, allows the evidence of all the changes which appears to layers flow and deformation through the gradually increasing of the revolution. Thus, it is possible to identify the transition or critical regime specific to different rheological types.