the steger and warming flux vector splitting implicit scheme is used to numerically solve two dimensional reynolds averaged navier–stokes (rans) equations governing the vortex induced vibration of a flexible riser laterally supported by a spring and a damper. the k–ε model is used as turbulence model to simulate the turbulent flow in the wake of the riser. to update the new position of the rise...

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...

5 Large eddy simulation (LES) is computationally extremely expensive for the investigation of wall-bounded turbulent flows at high Reynolds numbers. A way to reduce the computational cost of LES by orders of magnitude is to combine LES equations with Reynolds-averaged Navier-Stokes (RANS) equations used in the near-wall region. A large variety of such hybrid RANS-LES methods are currently in us...

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...

OBJECTIVE Review and synthesise the literature identifying the stresses experienced by remote area nurses (RANs). Identify interventions implemented to address identified stresses. Explore the use of the job demands-resources (JD-R) model. METHODS A comprehensive literature review was conducted using the meta-databases Ovid and Informit. SETTING Remote Australian primary health care centres...

Predictive capability of RANS and LES models to calculate incipient cavitation of water in a step nozzle is assessed. The RANS models namely, Realizable k-ɛ, SST k-ω and Reynolds Stress Model did not predict any cavitation, due to the limitation of RANS models to predict the low pressure vortex cores. LES WALE model was able to predict the cavitation by capturing the shear layer instability and...

The paper presents a comparison of several hybridization between RANS and LES, and their potential and limitations in an industrial context. The first part of the paper addresses an often eluded problem in the hybrid RANS/LES community: the importance of the baseline statistical model. A new robust low-Reynolds number eddy-viscosity model, derived from a Reynolds-stress model and accounting for...

The objective of this study is to evaluate a recently proposed dynamic hybrid Reynoldsaveraged Navier-Stokes (RANS)-Large Eddy Simulation (LES) modeling framework that seeks to effectively address issues regarding RANS-to-LES transition and explicit grid dependence inherent in most current hybrid RANS-LES (HRL) models. RANSto-LES transition in the investigated dynamic HRL (DHRL) model is based ...

in this paper, a two-dimensional reynolds averaged navier-stokes (rans) model is developed to simulate the shoaling, breaking and overtopping of a solitary wave over a vertical breakwater. turbulence intensity is described by using a k turbulence closure model and the free surface configuration is tracked by volume of fluid (vof) technique. to validate the numerical model the simulation result...

The seminar discusses basic concepts of turbulence modeling in computational fluid dynamics (CFD). There are two mainstreams present in the field of interest. The first one are so called Reynolds averaged Navier-Stokes (RANS) models. RANS models are most widely used nowadays. Therefore theoretical aspects of RANS models are presented in more detail. The second mainstream presents direct numeric...