DRDC Atlantic is collaborating with ANSYS Canada and the University of New Brunswick to develop an unsteady, six degrees-of-freedom, Reynolds Averaged Navier-Stokes (RANS) submarine maneuvering simulation capability. Initially, this is being used to evaluate emergency rising maneuvers. During these maneuvers, high negative angles of attack can occur which result in a roll instability not previo...

Abstract. Modern wind-turbine airfoil design requires robust performance predictions for varying thicknesses, shapes, and appropriate Reynolds numbers. The airfoils of current large offshore wind turbines operate with chord-based numbers in the range 3–15 million. Turbulence transition boundary layer is known to play an important role aerodynamics these near operating point. While lack predicti...

An intermittency transport equation for RANS modeling, formulated in local variables, is extended for roughness-induced transition. To predict roughness effects in the fully turbulent boundary layer, published boundary conditions for k and ω are used. They depend on the equivalent sand-grain roughness height, and account for the effective displacement of wall distance origin. Similarly in our a...

Based on the physics underlying turbulence anisotropy in the equilibrium and nonequilibrium limits, a new physically-based, fully-realizable, nonequilibrium k − 2 RANS model has been developed. The model is based on an effective strain rate tensor that accounts for the strain history to which the turbulence has been subjected. This new model is applied to four distinctly different test cases fo...

An entirely new approach to the large-eddy simulation (LES) of high-speed compressible turbulent flows is presented. Subgrid scale stress models are proposed that are dimensionless functions of the computational mesh size times a Reynolds stress model. This allows a DNS to go continuously to an LES and then a Reynolds-averaged Navier-Stokes (RANS) computation as the mesh becomes successively mo...

Understanding how airborne pathogens are transported through hospital wards is essential for determining the infection risk to patients and healthcare workers. This study utilizes Computational Fluid Dynamics (CFD) simulations to explore possible pathogen transport within a six-bed partitioned Nightingalestyle hospital ward. Grid independence of a ward model was addressed using the Grid Converg...

The turbulent potential model is a Reynolds averaged (RANS) turbulence model that is theoretically capable of capturing non-equilibrium turbulent flows at a computational cost and complexity comparable to two-equation models. The ability of the turbulent potential model to accurately predict nonequilibrium turbulent flows is evaluated in this work. The flow in a spanwise driven channel flow and...

ADREA-HF, which is a Computational Fluid Dynamics (CFD) code, is utilised in order to numerically study the flow and concentration fields within a street-canyon area. The selected site is Runeberg Str., a typical urban street canyon with an aspect ratio of approximately 1:1 in Helsinki, Finland. The ADREA-HF model is a transient, non-hydrostatic, dense transport code, especially developed for d...