Large eddy simulation (LES) is now seen more and more as a viable alternative to current industrial practice, usually based on problem-specific Reynolds-averaged Navier-Stokes (RANS) methods. Access to detailed flow physics is attractive to industry, especially in an environment in which computer modelling is bound to play an ever increasing role. However, the improvement in accuracy and flow d...

A series of RANS-based aerodynamic shape optimization for an 800-passenger blended-wing-body aircraft is performed. A gradient-based optimization algorithm and a parallel structured multiblock RANS solver with Spalart–Allmaras turbulence model are used. The derivatives are computed using a discrete adjoint method considering both frozen-turbulence and full-turbulence assumptions. A total of 274...

This paper presents a recent numerical study conducted by researchers at the National Renewable Energy Laboratory on a point absorber wave energy conversion (WEC) system using a Reynolds-averaged Navier–Stokes (RANS)-based Computational Fluid Dynamics (CFD) method. The device we studied was a two-body floating-point absorber (FPA) that operates predominantly in heave and generates energy from t...

Reynolds-averaged Navier–Stokes (RANS) methods often cannot predict shock/turbulence interaction correctly. This may be because RANS models do not account for the unsteady motion of the shock wave that is inherent in these interactions. Previous work proposed a shock-unsteadiness correction that significantly improves prediction of turbulent kinetic energy amplification across a normal shock in...

Numerical simulations of complex large-scale flow systems must capture a variety of physical phenomena in order to predict the flow accurately. Currently, many flow solvers are specialized to simulate one part of a flow system effectively, but are either inadequate or too expensive to be applied to a generic problem. As an example, the flow through a gas turbine can be considered. In the compre...

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...

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 ...

In the present study, we opted for a longitudinal design and examined rapid automatized naming (RAN) performance from two perspectives. In a first step, we examined the structure of RAN performance from a general cognitive perspective. We investigated whether rapid naming measures (e.g., digit RAN and color RAN) reflect a mainly domain-general factor or domain-specific factors. In a second step...

Nowadays there are wide possibilities to perform numerical studies of turbulent natural convection flows on the base of 3D unsteady formulations [1]. Direct Numerical Simulation (DNS) is the most attractive and reliable approach for getting a detailed knowledge on convection [2, 3]. However, DNS applications are practically limited by the case of simplified geometry and/or the Rayleigh numbers ...