Studies of the Flow Fields Created by Single Vertical Jets Directed Downwards upon a Horizontal Surface

The velocity and temperature conditions in the space surrounding a single nozzle discharging hot pas vertically downwards on to a horizontal surface have been studied. Except at very loii exit velocities, the amount of recirculation to an intake situated on the axis of the jet is small. Within limits , the d;rnamic head at ground level at a point away .-,.>(0 i 'li-from the axis is indepenknl of '.c. the height of the nozzle above the/*gkund. 5.~ 2 h13:;;::y L j These limits are decided by Yie s;~reod of the jet before it reache'$he 13 ground, and by the lateral ex-Lent of t!le je \'. Qf t before it separates and rxses." from the ground. A parameter including the initial velocity of the ~jet and its tem-$erature is used to define both the vertical penetration of the jet and its lateral extent if it strikes the ground. The rate of decay of dynamic head in t!le jet alon its axi s and ac?xss the ground has been studied. In transic;nt experiments, the rate of progress of the initial sLx-ead of the jet across the ground has been determined. Introduction Apparatus Transient temperatures in the field around the jet Initial rate of spread of the jet Steady-state velocity measurements 5.1 Velocity field at ground level 5.2 Velocity along axis of jet Horizontal extent of jet flow 6.1 Choice of correlating parameter 6.2 Experimental results .6.3 Effect of temperature ratio TJ/T,. Vertical extent of the jet Discussion of choice, of parameters 8.1 Velocity and temperature ratios 2; The buoyancy parameter, horizontal extent of flow The buoyancy parameter, vertical penetration of jet Conclusions References Detachable abstract cards NO.