Dynamic pressure loads associated with twin supersonic plume resonanceThe phenomenon of twin supersonic plume resonance is defined and studied as it pertains to high level dynamic loads in the inter-nozzle region of aircraft like the F-15 and B1-A. Using a 1/40th scale model twin jet nacelle with powered choked nozzles, it is found that intense internozzle dynamic pressures are associated with the synchrophased coupling of each plume's jet flapping mode. This condition is found most prevalent when each plume's jet flapping mode has constituent elements composed of the B-type helical instability. Suppression of these fatigue bearing loads was accomplished by simple geometric modifications to only one plume's nozzle. These modifications disrupt the natural selection of the B-type mode and thereby decouple the plumes.
Document ID
19860057963
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Seiner, J. M. (NASA Langley Research Center Hampton, VA, United States)
Manning, J. C. (NASA Langley Research Center Hampton, VA, United States)
Ponton, M. K. (PRC Kentron International Hampton, VA, United States)