In this paper, an adaptive mesh refinement technique is presented for simulation of compressible flows, which can effectively refine the in regions with shock waves and vortices. The present approach uses total energy per unit volume as indicator to capture vortical structures. approach, h-refinement strategy adopted. To save computational effort, flow variables on new are obtained from previou...

Abstract: Detached-eddy simulation (DES) based on the v-f Reynolds-averaged Navier-Stokes (RANS) model is developed and tested. The v-f model incorporates the anisotropy of near-wall turbulence, which is absent in other RANS models commonly used in the DES community. The v-f RANS model is modi ed in order that the proposed v-f -based DES formulation reduces to a transport equation for the subgr...

The concept of a vertical-axis spiral wind rotor is proposed and implemented in the interest of adapting it to air flows from all directions and improving the rotor’s performance. A comparative study is performed between the proposed rotor and conventional Savonius rotor. Turbulent flow features near the rotor blades are simulated with Spalart-Allmaras turbulence model. The torque coefficient o...

Large Eddy Simulation (LES) and Detached Eddy Simulation (DES) are applied to prediction and investigation of the ow around a sphere. DES is a hybrid approach in which the closure is a simple modi cation to the Spalart-Allmaras model, reducing to Reynolds-Averaged Navier-Stokes (RANS) in attached regions, and LES away from the wall . Calculations are performed at a Reynolds number, Re = 10, in ...

Two axisymmetric shock-wave / boundary-layer interaction (SWBLI) cases are used to benchmark oneand two-equation Reynolds-averaged Navier-Stokes (RANS) turbulence models. This validation exercise was executed in the philosophy of the NASA Turbulence Modeling Resource and the AIAA Turbulence Model Benchmarking Working Group. Both SWBLI cases are from the experiments of Kussoy and Horstman for ax...

Manoeuvring underwater vehicles experience complex three dimensional flow. Features include stagnation and boundary layer separation along a convex surface. The resulting free vortex sheet rolls up to form a pair of streamwise body vortices. The track and strength of the body vortex pair results in a nonlinear increase in lift with as body incidence increases. Consequently, accurate capture of ...

The unsteady discrete adjoint equations are utilized to construct objective function gradients for use in geometry optimization in large scale three-dimensional unsteady ow problems. An existing massively parallel unstructured Reynolds-averaged Navier-Stokes equations solver forms the basis for the framework used to solve both the primal and dual (adjoint) problems. The framework is also capabl...

A spectral element—Fourier method (SEM) for Direct Numerical Simulation (DNS) of the turbulent flow of non-Newtonian fluids is described and the particular requirements for non-Newtonian rheology are discussed. The method is implemented in parallel using the MPI message passing kernel, and execution times scale somewhat less than linearly with the number of CPUs, however this is more than compe...

The intent of shielding functions in delayed detached-eddy simulation methods (DDES) is to preserve the wall boundary layers as Reynolds-averaged Navier–Strokes (RANS) mode, avoiding possible modeled stress depletion (MSD) or even unphysical separation due to grid refinement. An entropy function f s is introduced to construct a DDES formulation for the k-ω shear stress transport (SST) model, wh...