Improved Turbulence Modelling Across Disparate Length Scales for Naval Computational Fluid Dynamics Applications

A research program to develop a modular turbulence modeling framework suitable for handling the disparate length scales inherent in naval aviation flowfields is proposed. The research seeks to provide accurate representation of multi-scale turbulent flows within an engineering-oriented framework by combining best practices using high-fidelity RANS/LES or DDES methods in the near-field wake region of an aerodynamic surface with vorticity confinement methods downstream. Combining both methods will permit simulations of interest on much coarser meshes than currently utilized to provide significant runtime savings. In Phase I, the turbulence modeling approach will be developed and tested for various unit validation problems, and demonstrated for a simplified rotating rotor blade wake. An experimental program will be developed to obtain detailed measurements of turbulent flows with interacting disparate length scales. These measurements will provide valuable validation data for the turbulence modeling approach. The proposing team consists of CRAFT Tech, which will develop and demonstrate the turbulence modeling approach, and Dr. Nathan Murray of the University of Mississippi, National Center for Physical Acoustics (NCPA), who will develop and execute the experimental portion of the program.