Heat transfer measurements in a heated jet-pipe flow issuing into a cold cross stream

Measurements are presented of mean temperature in a nonbuoyant heated jet issuing perpendicularly into a cold stream at velocity ratios R=0.25, 0.5, 1, and 2, and of velocity-temperature fluctuation statistics at R=0.5. The mean temperature profiles at the jet exit are found to be considerably nonuniform at low velocity ratios, indicating an early mixing between the cold and hot fluid. The extra rate of strain due to streamline curvature and the longitudinal and normal temperature gradients affect the rate of generation of temperature fluctuations and turbulent heat fluxes. There are regions of the flow where the streamlines are unstably curved but the generation of ∼(ϑ2) is damped. The eddy diffusivity is well behaved across the flow only at downstream positions where the turbulent Prandtl number has rather high values close to the wall and reaches values around 0.9 away from the wall.