The purpose of this study is to analyze the motion status of swimmers during their gliding stage using a numerical simulation method. This simulation strategy is conducted by solving the 3D incompressible Navier-Stokes equations using the Realizable k-ε turbulence closure equations in combination with the Six Degrees of Freedom (6-DOF) method. The uneven mass distribution of a swimmer and the r...

Turbulence closure models are evaluated for application to spilling and plunging breakers in the surf zone using open source computational fluid dynamics software. A new library of turbulence models for application to multiphase flows has been developed and is assessed for numerical efficiency and accuracy by comparing against existing laboratory data for surface elevation, velocity and turbule...

The aim of this paper is numerical and experimental study of the effects of flow hydraulics, pipe structure (particularly elastic behaviour) and submerged jet on leak behaviour. In this regard, experimental tests were performed on a high-pressure circulation set up. Experiments were performed on an old steel pipe and a High Density Polyethylene (HDPE) pipe discharged to the atmosphere in a wide...

It is experimentally shown that the nonclassical high Reynolds number energy dissipation behavior, C(ε)≡εL/u(3)=f(Re(M))/Re(L), observed during the decay of fractal square grid-generated turbulence (where Re(M) is a global inlet Reynolds number and Re(L) is a local turbulence Reynolds number) is also manifested in decaying turbulence originating from various regular grids. For sufficiently high...

A new modeling methodology for ripple dynamics driven by oscillatory flows using a Eulerian two-phase flow approach is presented in order to bridge the research gap between near-bed sediment transport via migration and suspended load dictated induced vortices. Reynolds-averaged equations fluid phase are solved two-dimensional vertical domain with k-ε closure turbulence particle stresses closure...

It is shown that, for stationary isotropic turbulence, Taylor’s well known dissipation surrogate Du/L can be derived directly from the Karman-Howarth equation and is in fact a surrogate for inertial transfer, which becomes equal to the dissipation, as the Reynolds number tends to infinity. The expression found for the dissipation rate ε is ε = A3u ′3 L [

A new model for turbulent flows in porous media developed in an accompanying paper [F.E. Teruel, Rizwan-uddin, A new turbulence model for porous media flows. Part I: Constitutive equations and model closure, Int. J. Heat Mass Transfer (2009), doi:10.1016/j.ijheatmasstransfer.2009.04.017.], in which new definitions of the macroscopic turbulence quantities are introduced, is analyzed and validate...

This work presents results of flow simulations performed with the commercial code CFX 11.0 in a PWR 5x5 rod bundle segment with a split vane spacer grid. The geometrical configuration and flow conditions used in the experimental studies performed by Karoutas were assumed in the simulations. To make the simulation possible with a limited computational capacity and acceptable mesh refinement, the...

In this paper, two-dimensional turbulent flows in different and complex geometries are simulated by using an accurate grid generation method. In order to analyze the fluid flow, numerical solution of the continuity and Navier-Stokes equations are solved using CFD techniques. Considering the complexity of the physical geometry, conformal mapping is used to generate an orthogonal grid by means of...

In a recent preprint, [CGJ], we showed that for the Dirichlet Laplacian ∆ on the unit disk, the wave trace Tr(eit √ ∆), which has complicated singularities on 2π − ε < t < 2π, is, on the interval 2π < t < 2π+ ε, the restriction to this interval of a C∞ function on its closure. In this paper we prove the analogue of this somewhat counter-intuitive result for the Friedlander model. The proof for ...