Investigation of Turbulent Jet Impingement in a Confined Crossflow
Final rept. 1 Sep 88-1 Dec 90,
LOUISIANA STATE UNIV BATON ROUGE DEPT OF MECHANICAL ENGINEERING
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Measurements and computations are reported for the flow of a turbulent jet discharging into a crossflow confined between two parallel plates. For jet-to-crossflow velocity ratios R equal to 2 and 4, mean and fluctuating velocity components are measured by a laser Doppler anemometer. High order statistics of the streamwise velocity and its time derivative have been measured in the plane of symmetry of a jet in a confined crossflow. The existence of universal similarity of the fine scale structure of a developing turbulent velocity field and the validity of original Kolmogorov local similarity theory and later formulations were investigated. Construction of normalized spectral for energy content, dissipation, and higher order moments enable an examination of the Reynolds number dissipation, and higher order moments enable an examination of the Reynolds number dependence of these functions for the Re sub lamda range from 16 to 800. Estimates of the Kolmogorov constant, mu, ranging from 0.27 to 0.43 were obtained with the arithmetic average equal to 0.38. The fractal dimension of the fine scale structure was estimated from the functional relationship between the flatness of the velocity time derivative and Re sub lambda. For unfiltered data, the fractal dimension was estimated to be 2.45. However, with a or - 12 sigma bandwidth, the fractal dimension increased to 2. 73.
- Fluid Mechanics