Experimental investigations of the effect of Reynolds number on a plane jet

Abstract

The effect of Reynolds number, Re =Uo,cH /μ , where Uo,c is the nozzle exit centreline velocity, H is the slot-opening width and n is the kinematic viscosity of air) on the velocity field of a turbulent plane jet from a radially contoured nozzle of aspect ratio 60 is investigated. Measurements are conducted using a single wire anemometer over an axial distance of 160h. The Reynolds number is varied between 1,500 and 16,500. Results show that the Re affects various flow properties such as the velocity decay rate, half-width and turbulence intensity. The significant dependence on Re of the mean flow field persists till Re = 16,500, while the Re effect on the turbulent properties becomes weaker above Re = 10,000. The present investigation also suggests that an increase in Re leads to a higher rate of mixing in the near field but a lower rate in the far field.