THERMAL WAKE DOWNSTREAM OF A 3-DIMENSIONAL OBSTACLE

The temperature distribution within the thermal wake downstream of a t hree-dimensional obstacle mounted in a horizontal water channel is inv estigated. Temperature measurements are obtained at channel height-bas ed Reynolds numbers of 500-1500 (laminar) and 10,000-25,000 (turbulent ). Flow visualizations are used to elucidate the flow patterns in the separation region. The experimental results are compared with numerica l simulations of the laminar flow field and thermal wake. In laminar f low, the wake temperature was found to increase with increasing Reynol ds number and decreasing buoyancy effects. In the turbulent regime, th e flow structures and measured wake temperatures were largely unaffect ed by the Reynolds number and buoyancy. The numerical models of the fl ow field were in reasonable agreement with the flow visualizations and with similar results in the literature. Reasons for the small discrep ancies in the predicted and measured wake temperatures at the higher l aminar Reynolds numbers are discussed.