RANS and Hybrid RANS-LES Simulations of an H-Type Darrieus Vertical Axis Water Turbine

An extensive study on LES, RANS and hybrid RANS/LES simulation of a narrow-gap open Taylor-Couette flow

The present paper concerns a numerical benchmark of various turbulence modelings, from RANS to LES, applied to Taylor-Couette-Poiseuille flows in a narrow gap cavity for six different combinations of rotational and axial Reynolds numbers. Two sets of refined Large-Eddy Simulation results, using the WALE and the Dynamic Smagorinsky subgrid scale models available within an in-house code based on ...

Unsteady aerodynamic performance of Dual-Row H-Darrieus vertical axis wind turbine

H-rotor Vertical Axis Wind Turbine (VAWT) is one of the most efficient energy suppliers which have been investigated in many recent types of research. The aim of this work is to study the aerodynamic performance of a doubled-row H-Darrieus VAWT. First, an ordinary three-bladed VAWT with NACA4415 profile is simulated by means of 3D computational fluid dynamics (CFD) and results are compared to a...

Hybrid RANS/LES computation of plane impinging jet flow

Flow characteristics are presented of simulation results of plane impinging jets at high nozzle-plate distances, with two k-ω based hybrid RANS/LES (Reynolds Averaged Navier–Stokes/Large–Eddy Simulation) models and a k-ω RANS model. The first hybrid RANS/LES model is obtained by substitution of the turbulent length scale by the local grid size in the destruction term of the turbulent kinetic en...

مطالعه انواع رهیافت های ترکیبی LES/RANS

A New Formulation for Hybrid LES-RANS Computations

Ideally, a hybrid LES-RANS computation would employ LES only where necessary to make up for the failure of the RANS model to provide sufficient accuracy or to provide time-dependent information. Current approaches are fairly restrictive in the placement of LES and RANS regions; an LES-RANS transition in a boundary layer, for example, yields an unphysical log-layer shift. A hybrid computation is...