Volume 103, Issue 1, January 1998
Index of content:
- AEROACOUSTICS, ATMOSPHERIC SOUND 
103(1998); http://dx.doi.org/10.1121/1.421114View Description Hide Description
A modelexperiment to study the effect of atmospheric turbulence on sonic booms is reported. The modelsonic booms are waves produced by electric sparks, and the modelturbulence is created by a plane jet. Of particular interest are the changes in waveform, peak pressure, and rise time of the model waves after they have passed through the modelturbulence. A review is first given of previous experiments on the effect of turbulence on both sonic booms and model waves. This experiment was designed so that the scale factor (approximately ) relating the characteristic length scales of the modelturbulence to those of atmospheric turbulence is the same as that relating the model waves to sonic booms. Most of the results reported are for plane waves. Sets of 100 or 200 pressure waveforms were recorded, for both quiet and turbulent air, and analyzed. Sample waveforms, scatter plots of peak pressure and rise time, histograms, and cumulative probability distributions are given. Results are as follows: (1) The modelexperiment successfully simulates sonic boom propagation through the atmosphere. The waveform distortion of actual sonic booms is reproduced, both in scale and in character, in the laboratory study. (2) Passage through turbulence almost always causes rise time to increase; decreases are rare. (3) Average rise time is always increased by turbulence, threefold for the particular data reported here. (4) Average peak pressure is always decreased by turbulence, but the change is not as striking as that for average rise time.