Computational Analyses of Offset-Stream Nozzles for Noise Reduction

The W ind c omputational fluid dyn amics code was used to perform a series of simulations on two offset stream nozzle concepts for jet noise reduction. The first concept used an S -duct to direct the secondary stream to the lower side of the nozzle. The second concept used vanes to turn th e secondary flow downward. The analyses were completed in preparation of tests conducted in the NASA Glenn Research Center Aeroacoustic Propulsion Laboratory. The offset stream nozzles demonstrated good performance and reduced the amount of turbulence on the lower side of the jet plume. The computer analyses proved instrumental in guiding the development of the final test configurations and giving insight into the flow mechanics of offset stream nozzles. The computational predictions were compared with flowfield results from the jet rig testing and showed excellent agreement.

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