predicting the quality of water and air is a particular challenge for forecasting systems that support them. in order to represent the small-scale phenomena, a high-resolution model needs accurate capture of air and sea circulations, significant for forecasting environmental pollution. data assimilation is one of the state of the art methods to be used for this purpose. due to the importance of...

A severe case of stenosis in coronary arteries results in turbulence in the blood flow which may lead to the formation or progression of atherosclerosis. This study investigated the turbulent blood flow in a coronary artery with rigid walls, as well as 80% single and double stenoses on blood flow. A finite element-based software package, ADINA 8.8, was employed to model the blood flow. The hemo...

This paper presents finite volume method based on Reynolds-averaged Navier-Stokes (RANS) equations for computation of 2D axisymmetric flow around bare submarine hull using unstructured grid. The body used for this purpose is a standard DREA (Defence Research Establishment Atlantic) bare submarine hull. Shear Stress Transport (SST) k-ω model has been used to simulate turbulent flow past the hull...

The present work is to evaluate the performance of RANS turbulence models for simulating regular wavepropagation over a submerged breakwater using open-source Computational Fluid Dynamics (CFD) software OpenFOAM. numerical results four (k-ε model, k-ω SST buoyancy-modified and stabilized model) are compared with published experimental data free surface elevations velocities at gauges. Moreover,...

Abstract A study into the effect of tip clearance on ducted propellers was carried out. Two series propellers, namely B-series and Kaplan-series, were used. The gap between propeller varied from 2mm to 5mm. conducted numerically using computational fluid dynamics (CFD) approach. solver is based Reynolds-Averaged Navier-Stokes (RANS) solutions two turbulence modelling, i.e. k-ω SST by Menter exp...

Two-equation turbulence models, such as the k–epsilon (k–ε) and shear stress transport (SST) have limited accuracy in calculating film cooling effectiveness. Previous studies focused on modifying turbulent Prandtl number from perspective of thermal diffusion to improve prediction simulations. However, flow jet is crucial for simulating cooling. The calculated effectiveness differs experimental ...

In this study, modeling of a fuel jet which has been injected by high pressure into a low-pressure tank are investigated. Due to the initial conditions and the geometry of this case and similar cases (like CNG injectors in internal combustion engines (ICE)), the barrel shocks and Mach disk are observed. Hence a turbulence and transient flow will be expected with lots of shocks and waves. Accord...

Based on the solid–liquid two-phase flow model, SST k-ω and Lagrangian equation model of particle motion, numerical simulations sediment–water in injector a large Pelton turbine were conducted. The distribution rules pressure, velocity, erosion rate, location obtained by analyzing characteristics sediment injector. results revealed that velocity trend water inside cylindrical jet exhibited nonl...

A wall–distance–free version of the Spalart–Allmaras (SA) one–equation model is proposed to account for the distinct effects of low-Reynolds number (LRN) and wall proximity. The turbulent kinetic energy k and the dissipation rate ǫ are evaluated using the ν̃t–transport equation together with some empirical relations. The model coefficients/functions preserve the anisotropic characteristics of tu...