Mean flow characteristics of a 3D turbulent wall jet over an isothermal and an insulating flat surface

An experimental study was carried out on the mean aerodynamic and heat-exchange characteristics of a weaklyheated air jet flowing over an isothermal and an insulating flat surface. The jet issued from a contracting profiled rectangular nozzle (39×22 m² outlet) at 30 m/sec velocity (Re _d =~5.5×10⁴) and incidence angle α₀, π/12, π/6, π/4. It was established that as α₀ increases, so do the decay rates of the axial velocity and temperature along the jet axis as well as the jet width, while the jet thickness decreases. Parallel examination of an in sulating and an isothermal surface permitted separation of the heat-exchange process between the jet and the surrounding medium, from that between the jet and the wall surface-with the conclusion tha tin the isothermal case, the exchange with the surface intensifies as α₀ increases.