Turbulence Framework for Jet Noise Prediction and Reduction

The innovation proposed is the construction of a unified nonlinear turbulence model for use in jet noise studies that will operate in an invariant manner (fixed coefficients/correction terms), and will provide reliable mean flow and anisotropic stresses predictions for a broad range of jet conditions. Model construction will be based on extensions to an operational explicit algebraic stress model (EASM) framework that includes anisotropic dissipation, compressibility, and vortex-stretching extensions, and is supplemented by additional scalar fluctuation and dissipation rate equations used to locally evaluate turbulent Prandtl and Schmidt numbers. CRAFT Tech will be supported by Seiner and coworkers at U. Miss who will obtain 3D PIV data for Mach .85 and 1.5 cold and hot jets to support model calibration. Acoustics data will also be obtained in this effort, and simulations performed via coupling the CFD solution with an acoustics analogy noise code (such as MGB) will be compared with this data. In Phase II, the model will be extended to more complex 3D propulsive jets that include varied mixing enhancement devices. In addition, propulsive interfacing and aerodynamic interactions will be addressed.