Both RaNS (Reynolds-averaged Navier-Stokes) and DES (Detached Eddy Simulation) type turbulence models were used in conjunction with a two-fluid model of bubbly flow and a new subgrid air entrainment model to predict air entrainment and transport in a hydraulic jump. It was found that the void fraction profiles predicted by both methods are in agreement with the experimental data in the lower sh...

This paper investigates the influence of the propeller on the drag of twin self-propelled AUVs, firstly, to examine the fleet performance for various propulsive conditions of leading and following AUV and, secondly, to study the parametric influence of transverse separations and longitudinal offsets on the fleet’s drag. A series of CFD RANS-SST simulations have been performed at the Reynolds Nu...

In this paper, a gas kinetic solver is developed for the Reynolds Average Navier-Stokes (RANS) equations in two-space dimensions. To our best knowledge, this is the first attempt to extend the application of the BGK (Bhatnagaar-Gross-Krook) scheme to solve RANS equations with a turbulence model using finite difference method. The convection flux terms which appear on the left hand side of the R...

As identified in the CFD Vision 2030 Study commissioned by NASA, validation of advanced RANS models and scale-resolving methods for computing turbulent flow fields must be supported by continuous improvements in fundamental, high-fidelity experiments designed specifically for CFD implementation. In accordance with this effort, the underpinnings of a new test platform referred to herein as the N...

Oil droplet transport under a non-breaking deep water wave field is investigated herein using Computational Fluid dynamics (CFD). The Reynolds-averaged Navier–Stokes (RANS) equations were solved to simulate regular waves in the absence of wind stress, and the resulting water velocities agreed with Stokes theory for waves. The RANS velocity field was then used to predict the transport of buoyant...

Three different cyclist positions were evaluated with Computational Fluid Dynamics (CFD) and wind-tunnel experiments were used to provide reliable data to evaluate the accuracy of the CFD simulations. Specific features of this study are: (1) both steady Reynolds-averaged Navier-Stokes (RANS) and unsteady flow modelling, with more advanced turbulence modelling techniques (Large-Eddy Simulation -...

3G Radio Access Networks (RANs) generally have to transport traffic with a variety of heterogeneous Quality of Service (QoS) requirements. In today’s 3G RANs, Asynchronous Transfer Mode (ATM) technology is used to provide the desired QoS. However, packet based RANs have been subject to recent standardization. In this case, Differentiated Services can be deployed to offer the required QoS using ...

The numerical analysis of the mechanisms governing the flow in the porous region is of a priority interest for modeling porous media flows. The present study is a prerequisite for elaborating the efficient turbulence modeling techniques in porous media flows. The main objective of present study is to provide a detailed pore scale description of fluid flow and to analyze the formation of the coh...

The present work is part of a research effort aimed at integrating a detailed model of airflow in large spaces with an algebraic multizone infiltration model to describe pollutant transport and coupled air flows within and between complex buildings and large spaces. In the past 15 years, zonal models were developed with the goal to obtain an approximate prediction of airflow characteristics in ...

The use of RANS models in the analysis of the urban climate and in air quality studies has become increasingly popular when predictions have to deal with complex flows, such as those arising at the street-scale. The need for model assessment and validation has thus also become crucial towards establishing the reliability of RANS simulations of heat and mass transport in urban areas. In this res...