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Journal ArticleDOI

Computational analysis of three-dimensional turbulent flow around a bluff body in ground proximity

Taeyoung Han
- 01 Sep 1989 - 
- Vol. 27, Iss: 9, pp 1213-1219
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TLDR
In this article, Ahmed's vehicle-like body in ground proximity was modeled as a k-e model of turbulent flows and the Reynolds-averaged Navier-Stokes equations were solved numerically in a general curvilinear coordinate system for three-dimensional turbulent flows around Ahmed's body.
Abstract
The Reynolds-averaged Navier-Stokes equations, together with the equations of the k-e model of turbulence, were solved numerically in a general curvilinear coordinate system for three-dimensional turbulent flows around Ahmed's vehicle-like body. The numerical computations were performed for various afterbody upper-surface slant angles at a constant Reynolds number of 4.3 x 10 based on the body length. A multistep correction procedure was incorporated into the incompressibility condition, and the solution of the Poisson equation for pressure was obtained from the conjugate gradient method. A second-order discretization scheme for the convection term was applied to reduce the numerical diffusion. Most of the essential measured features of the flowfield around Ahmed's vehicle-like body in ground proximity, such as the formation of trailing vortices and the reverse flow region resulting from separation, were well predicted.

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Citations
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Journal ArticleDOI

Flow around a simplified car, Part 1: Large eddy simulation

TL;DR: In this article, large eddy simulations (LES) were made of flows around a generic ground vehicle with sharp edges at the rear end (an Ahmed body with a 25° angle of the rear slanted surface).
Journal ArticleDOI

Recent experience with different methods of drag prediction

TL;DR: In this article, a review of recent experiences in CFD-based drag prediction with an emphasis on flow solutions governed by the Euler and Reynolds-averaged Navier-Stokes equations is presented.
Journal ArticleDOI

High-order large-eddy simulation of flow over the “Ahmed body” car model

TL;DR: In this article, the structure of the turbulent flow over a simplified automotive model, the Ahmed body (S. R. Ahmed and G. Ramm, 1984) with a 25° slanted back face, is investigated using high-order large-eddy simulations (LESs) at Reynolds number Re=768000.
Journal ArticleDOI

Aerodynamics of Heavy Vehicles

TL;DR: In this paper, the authors present an overview of the aerodynamics of heavy vehicles, such as tractor-trailers, high-speed trains, and buses, and discuss the flow-control devices used for drag reduction.
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Numerical Study of the Flow Around a Bus-Shaped Body

TL;DR: In this paper, a detailed survey of both instantaneous and time-averaged flows is made and a comparison with previous knowledge on similar flows is presented, besides the coherent structures observed in experimental and previous numerical studies, new smaller-scale structures were registered.
References
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Journal ArticleDOI

The numerical computation of turbulent flows

TL;DR: In this paper, the authors present a review of the applicability and applicability of numerical predictions of turbulent flow, and advocate that computational economy, range of applicability, and physical realism are best served by turbulence models in which the magnitudes of two turbulence quantities, the turbulence kinetic energy k and its dissipation rate ϵ, are calculated from transport equations solved simultaneously with those governing the mean flow behaviour.
Journal ArticleDOI

Methods of Conjugate Gradients for Solving Linear Systems

TL;DR: An iterative algorithm is given for solving a system Ax=k of n linear equations in n unknowns and it is shown that this method is a special case of a very general method which also includes Gaussian elimination.
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A calculation procedure for heat, mass and momentum transfer in three-dimensional parabolic flows

TL;DR: In this article, a general, numerical, marching procedure is presented for the calculation of the transport processes in three-dimensional flows characterised by the presence of one coordinate in which physical influences are exerted in only one direction.
Journal ArticleDOI

Numerical solution of the Navier-Stokes equations

TL;DR: In this paper, a finite-difference method for solving the time-dependent Navier-Stokes equations for an incompressible fluid is introduced, which is equally applicable to problems in two and three space dimensions.
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Numerical Study of the Turbulent Flow Past an Airfoil with Trailing Edge Separation

TL;DR: In this paper, a methode numerique par volume fini pour the resolution des equations de Navier-Stokes bidimensionnelles, incompressible, and stationnaires, en coordonnees generales curvilignes, is presented.