High Resolution Measurement of the Flow Velocity Field in a Supersonic Jet Plume

Modern supersonic jet aircraft engines produce a high amplitude noise field with complicated characteristics due to turbulent behaviors of the hot jet. Researchers need better understanding of the turbulent structures in the jet plume to develop treatments to engines that might reduce the noise emissions. A significant obstacle to making these simulations practical and realistic for engine design purposes is the lack of methodology to measure the velocity field of the jet plume for purposes of correlating computational results. High quality measurements of the velocity field at and ahead of the exhaust nozzle exit plane would improve the upstream boundary condition. A further need for this technology is for imaging the supersonic and subsonic turbulent flow field around a STOVL aircraft to understand the safety and other impacts of the flow field on support personnel and equipment. The proposed instrumental solution works without the addition of imaging particles or fluids to the jet engine intake or exhaust and also works with flows that are not combustion byproducts. This measurement method affords sufficient time resolution to track the advection of both large and small scale turbulent structures in a supersonic jet plume and will also work in the subsonic case.