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.