Improved Turbulence Modelling Across Disparate Length Scales for Naval Computational Fluid Dynamics Applications Navy STTR FY2015.A Sol No.: Navy STTR FY2015.A Topic No.: N15A-T002 Topic Title: Improved Turbulence Modelling Across Disparate Length Scales for Naval Computational Fluid Dynamics Applications Proposal No.: N15A-002-0064 Firm: Combustion Research and Flow Technology, Inc. 6210 Kellers Church Road Pipersville, Pennsylvania 18947-1020 Contact: Jeremy Shipman Phone: (215) 766-1520 Abstract: 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. Benefits: Upon completion of this STTR, a generalized turbulence modeling framework suited for unsteady simulations for highly turbulent flows will be developed and demonstrated. Key aspects to this effort include framework modularity, validated accuracy, and reduced computational cost relative to analogous solution methods. These aspects not only make it straightforward for incorporation into existing Navy CFD tools and simulation environments, but also result in significant commercial potential for the technology developed in this program. In addition to the immediate application to rotorcraft downwash/ship airwake interactional effects, we see near-term marketing potential of the capabilities developed during this STTR effort in a number of growth areas in the aerospace industry. Potential applications include wind turbine blade design and noise mitigation, UAV propulsion integration design, improved ship-aircraft Dynamic Interface (DI) simulations for aircraft launch and recovery, ship superstructure and deck aerodynamic environment design for new ship designs such as DDX and LCS, and improved modeling and simulation for manned flight simulation. Our commercialization plan entails a dual strategy to: (a) Actively pursue contractual and sub-contractual efforts in support of DoD and commercial technology areas identified above; and, (b) License simulation software resulting from this effort to the aerospace industry. Return