In the flow-establishment region of an air jet issuing with an efflux velocity of about 35 ft./sec from a 1.0 ft. diameter nozzle into still air, measurements were made of mean axial and radial velocities, mean static pressure, turbulence intensities, turbulent shear, and pressure fluctuation. For the measurement of the latter a pressure probe using a ceramic piezo-electric tube was developed. Also included in the measurements were the temporal mean gradient and autocorrelation of the axial-velocity fluctuation and the intermittency factor. The fluctuating-pressure and turbulence-intensity fields were observed to be closely similar in form. Through use of the measured distributions of mean-flow and turbulence characteristics, all terms of the integral and differential forms of the momentum and mean-energy equations were evaluated throughout the region. The results are presented herein by curves of variation of each of the terms as they appear in the corresponding equations.
To complete a previous investigation reported earlier and carried out in an air jet issuing from a 1·0ft. diameter nozzle into still air, additional measurements were made of one-point triple-velocity and two-point double-velocity correlations and the spatial mean gradients of the axial turbulent velocities. The one-point pressure/axial-velocity correlation term was evaluated by using piezo-electric ceramic elements in conjunction with total- and static-pressure probes. For the measurement of spatial mean gradients of the axial-velocity fluctuation, special probes with two parallel wires were constructed. The axial scale of turbulence was found to be almost twice as large as the other two scales. The tangential scale was the smallest. All terms of the integral and differential forms of the turbulence energy equation were evaluated throughout the region and the results are given in dimensionless form.
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