Portable Acoustical Holograph System For Visualizing Jet Plumes

This SBIR Phase I Project will examine the feasibility of commercializing an innovative technology, known as the Helmholtz Equation Least Square (HELS) based Nearfield Acoustical Holography (NAH), to visualize the acoustic characteristics of jet plumes from high performance military fighter engines and those from high bypass commercial transport engines. The ultimate goal of this project is to provide engineers with a robust and portable acoustical holography tool to obtain the 3D image and characteristics of the acoustic field produced by full-scale jet engine. Users of this tool will acquire in-depth understanding of jet noise that cannot be obtained by conventional measurements and analyses technologies. Specifically, engineers will be able to overlay 3D images of a sound field produced by a jet engine on top of a jet plume. By slicing a 3D sound field from various angles and viewing it from different perspectives together with a 3D velocity field produced by a jet engine, engineers will be able to correlate jet noise to jet stream. In particular, engineers will be able to identify the sound source frequency dependent spatial distribution, examine the time varying acoustic shock structure in a plume, and quantify the major acoustic radiation angles and strength. The insight and knowledge gained will allow engineers to devise most cost-effective ways to reduce jet noise. The improved designs will lead to a quieter jet engine that can have a significant military advantage and benefit the public in general.