This report presents an evaluation of the steady-state capability of the turbulence models available in the commercial CFD code FLUENT 6.0, for their application to the simulation of hydrofoil turbulent boundary layer separation at high-Reynolds numbers. Four widely applied two-equation RANS turbulence models were qualitatively and quantitatively assessed through comparison with high-quality ex...

sediment flushing of reservoirs is an operational technique, whereby previously accumulated sediments in the reservoirs are hydraulically removed by accelerated flow when the bottom desiltingoutlets of the dam are opened. in this research, the process of sediment flushing is simulated by a three dimensional numerical model in which sediment and flow interaction are reflected in the reservoirs. ...

This paper presents a numerical solution for a changing combustor geometry. The effects of the geometric change on the main parameters of the chamber are considered. For this purpose the original geometry and the new one are simulated numerically by a 3-D CFD code and the results are compared. Finally, comments are presented regarding this change. A model is used for turbulence modeling and a...

This paper presents a numerical solution for a changing combustor geometry. The effects of the geometric change on the main parameters of the chamber are considered. For this purpose the original geometry and the new one are simulated numerically by a 3-D CFD code and the results are compared. Finally, comments are presented regarding this change. A model is used for turbulence modeling and a...

Heated from above, the oceans are stably stratified. Therefore, the performance of general ocean circulation models and climate studies through coupled atmosphere-ocean models depends critically on vertical mixing of energy and momentum in the water column. Many of the traditional general circulation models are based on total kinetic energy (TKE), in which the roles of waves are averaged out. A...

A numerical simulation has been performed of the disturbed flow through and over a twodimensional array of rectangular buildings immersed in a neutrally stratified deep roughwalled turbulent boundary-layer flow. The model used for the simulation was the steady-state Reynolds-averaged Navier-Stokes equations with linear and non-linear eddy viscosity formulations for the Reynolds stresses. The ed...

A simple model to determine a turbulence effect in formation of the Antarctic Circumpolar Current (ACC) is suggested. The model is founded on the theory of rotationally anisotropic turbulence and is set up as a generalization of the geostrophic description of the Antarctic Circumpolar Current (ACC). It predicts the turbulence effect as an additive correction to the flow velocity predicted by th...

Helicity transfer in a shell model of turbulence is investigated. In particular, we study the scaling behavior of helicity transfer in a dynamical model of turbulence lacking inversion symmetry. We present some phenomenological and numerical support to the idea that Helicity becomes -at scale small enougha passively-advected quantity. “oυτoι συνǫχθǫιν, αλλα συμφιλǫιν ǫφυν” ANTIΓONH “non sono na...

Laser speckle can influence lidar measurements from a diffuse hard target. Atmospheric optical turbulence will also affect the lidar return signal. We present a numerical simulation that models the propagation of a lidar beam and accounts for both reflective speckle and atmospheric turbulence effects. Our simulation is based on implementing a Huygens-Fresnel approximation to laser propagation. ...

This paper describes a study of the self-sustaining process in wall turbulence. The study is based on a second order statistical state dynamics model of Couette flow in which the state variables are the streamwise mean flow (first cumulant) and perturbation covariance (second cumulant). This statistical state dynamics model is closed by either setting the third cumulant to zero or by replacing ...