Super-linear speed-up of a parallel multigrid Navier-Stokes solver on Flosolver

In parallel computing, scalability is an important issue and getting linear speed-ups is difficult for most codes. Super-linear speed up has been achieved on an eight-processor Flosolver system for a multigrid Navier-Stokes code. The physical problem solved, the parallelization method, the speed-ups obtained and possible explanations for this result are discussed here

CHANCE: A FRENCH-GERMAN HELICOPTER CFD-PROJECT

The paper gives an overview of the CHANCE research project (partly supported by the French DPAC and DGA and the German BMWA) which was started in 1998 between the German and French Aerospace Research Centres DLR and ONERA, the University of Stuttgart and the two National Helicopter Manufacturers, Eurocopter and Eurocopter Deutschland. The objective of the project was to develop and validate CFD tools for computing the aerodynamics of the complete helicopter, accounting for the blade elasticity by coupling with blade dynamics. The validation activity of the flow solvers was achieved through intermediate stages of increasing geometry and flow modelling complexity, starting from an isolated rotor in hover, and concluding with the time-accurate simulation of a complete helicopter configuration in forward-flight. All along the research program the updated versions of the CFD codes were systematically delivered to Industry. This approach was chosen to speed up the transfer of capabilities to industry and check early enough that the products meet the expectations for applicability in the industrial environment of Eurocopter

Advances and Challenges in Computational Research of Micro and Nano Flows

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.This paper presents a collective overview of recent studies regarding the computational modelling of micro- and nano-fluidic systems. The review provides an introduction to atomistic, mesoscale and hybrid methods for simulating micro and nano-flows, as well as discusses recent applications and results from the application of such methods

A coupled finite-volume CFD solver for two-dimensional elasto-hydrodynamic lubrication problems with particular application to rolling element bearings

This paper describes a new computational fluid dynamics methodology for modelling elastohydrodynamic contacts. A finite-volume technique is implemented in the ‘OpenFOAM’ package to solve the Navier-Stokes equations and resolve all gradients in a lubricated rolling-sliding contact. The method fully accounts for fluid-solid interactions and is stable over a wide range of contact conditions, including pressures representative of practical rolling bearing and gear applications. The elastic deformation of the solid, fluid cavitation and compressibility, as well as thermal effects are accounted for. Results are presented for rolling-sliding line contacts of an elastic cylinder on a rigid flat to validate the model predictions, illustrate its capabilities, and identify some example conditions under which the traditional Reynolds-based predictions deviate from the full CFD solution

Turbulent shear layers in confining channels

We present a simple model for the development of shear layers between parallel flows in confining channels. Such flows are important across a wide range of topics from diffusers, nozzles and ducts to urban air flow and geophysical fluid dynamics. The model approximates the flow in the shear layer as a linear profile separating uniform-velocity streams. Both the channel geometry and wall drag affect the development of the flow. The model shows good agreement with both particle-image-velocimetry experiments and computational turbulence modelling. The low computational cost of the model allows it to be used for design purposes, which we demonstrate by investigating optimal pressure recovery in diffusers with non-uniform inflow

Institute for Computational Mechanics in Propulsion (ICOMP)

The Institute for Computational Mechanics in Propulsion (ICOMP) is a combined activity of Case Western Reserve University, Ohio Aerospace Institute (OAI) and NASA Lewis. The purpose of ICOMP is to develop techniques to improve problem solving capabilities in all aspects of computational mechanics related to propulsion. The activities at ICOMP during 1991 are described