PIV measurements of turbulent flows in a smooth channel with the heated boundary under rotation conditions

Abstract

In the current study, turbulent flow was measured in a smooth channel by PIV with heated boundary under rotation conditions. The experiments were carried out with Re=10,000, and rotation numbers ranging from 0 to 0.52. The four channel walls were heated with ITO heater glass, making the density ratio equaling about 0.1 and the maximum value of buoyancy number up to 0.27. Turbulent flow was measured at the position of 3.5<X/D<6.5 and 0<Y/D<1 in the middle plane of channel (Z/D=0.5) under the effect of Coriolis force and buoyancy force. The velocity profile and Reynolds shear stress with and without the effect of the buoyancy force were taken into consideration in current work. Separated flow was obtained experimentally for the first time on the leading surface owing to the effect of buoyancy force. The initial position of separated flow (Xc/D) has a reverse relation with rotation numbers. Velocity profile altered significantly under the effect of Coriolis and buoyancy force, which causes a leap increase of Reynolds shear stress (τxy) on the leading surface when the separated flow happened. Buoyancy force enhances τxy on the trailing side. The flow behaviors captured in the current work can confirm that buoyancy force causes the separated flow, and causes the critical point of heat transfer on the leading surface.