Input - output analysis of high - speed jet noise
نویسندگان
چکیده
We use input-output analysis to examine subsonic and supersonic turbulent jet noise. For a supersonic jet, the leading input-output mode closely resembles wavepackets resulting from the parabolized stability equations (PSE). For a subsonic jet, however, input-output analysis produces several sub-optimal modes with nearly the same gain as the leading input-output mode. The sub-optimal modes depend upon spatially extended input forcings and thus cannot be predicted by PSE. This may explain why PSE modes successfully predict far-field acoustics of supersonic jets but severely underpredict the farfield acoustics of subsonic jets.
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