1 Computational and Experimental Investigation of Fan Flow

We present a combined experimental and computational study of the dual-stream exhaust of a supersonic turbofan engine with noise-suppressing deflectors installed in the fan stream. The focus is on validating the computational code, extracting turbulent kinetic energy (TKE) trends, and connecting those trends to the measured noise reduction. We consider two operating conditions, a “cold ” condition at which mean flow surveys were conducted and against which the code was validated; and a “hot ” condition that corresponds to the takeoff engine cycle and at which acoustic measurements were conducted. A three-dimensional Reynolds-Averaged Navier Stokes code is used to simulate the flow for a number of nozzle configurations using vane type flow deflectors to create asymmetric jet plumes, which have demonstrated experimentally the potential for significant noise reduction. The code successfully replicates the mean velocity, radial velocity gradient and inflectional layer fields of the experimental flows. Comparison of “cold ” and “hot ” condition shows a reasonable collapse of the velocity profiles when the axial distance is normalized by the potential core length. For both conditions, the vane deflectors reduce the TKE on the underside of the jet and increase it on the topside of the jet. There is a significant correlatio