1. 6-11 represent most of the work which has been directed towards the IEIn-jet screech problem. It was shown by Seiner that the twin-jet coupling process can increase the screech tone amplitude by 6 dB factor of 4). Full scale yround run-up data ($7 from an F-15 aircraft also show a narrowband tone near the predicted screech frequyy. Wind tunnel data for a 6 Dercent B-1A model show some narrowband tones, but not as well deFined as the ground run-up data.#jnd tunnel data fur the 8.3 percent F-15 model 'O' also shows some narrowband(yyyrgy but at low levels. It i s well eztablished that the conditions of the flow at the exit plane can significantly affect the feedback process. The velocity profile and turbulence level can both affect the screech phenomenon. One can see the problem of trying t o scale screech data from test stands, wind tunnels, and flight. Both velocity profile and turhulence level of the flow at Ih? 3 exit plane are different .For each case.
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3. Tab Configurations