Velocity and Temperature Measurements in a Turbulent Natural Convection Boundary Layer in Water

For a natural convection turbulent boundary layer in water along a vertical flat plate, measurements such as mean velocities, mean temperature, velocity and temperature fluctuation intensities. Reynolds shear stress and turbulent heat fluxes are obtained with a particle image velocimetry and a thermocouple rake. To confirm measurement accuracies, a direct numerical simulation for a time-developing natural convection boundary layer is also conducted. The measured results coincide relatively well with those obtained from the direct numerical simulation and, consequently, it is found that the turbulence characteristics of the boundary layer in water are similar to those in air, although the turbulent heat fluxes become fairly smaller than those for air due to the effect of high Prandtl number.