Simultaneous measurements of velocity and temperature of the natural convection flow on a heated rotating disc

Simultaneous measurements of velocity and temperature fluctuation in the natural convection flow on a heated rotating disc were conducted by using laser Doppler velocimetry (LDV) and laser induced fluorescence technique (LIF). Flow visualization was also made by using dye injection method. In the laminar and natural convection dominant region, circumferential vortices appeared on the heated rotating disc. The visualization of the flow revealed that the circumferential vortex was developed from a thermal plume appearing near the wail. Ensemble averages of the velocity and temperature in the circumferential vortex were obtained by a conditional analysis of the time series of velocity and temperature fluctuations. The result shows that the circumferential vortex has a rotational motion of the scale nearly same as the thickness of the velocity boundary layer on the rotating disc. The heat transfer due to the thermal plume is dominant in the central region of the disc and that due to the wallward flow of low temperature in the vortices becomes important in the peripheral region of the disc.