Separated Flows Behind Bluff Bodies Including Ground Effects: Application of The Zonal Method

1993 ◽  
pp. 297-300
Author(s):  
Heinz-D. Papenfuss ◽  
Klaus Gersten
Keyword(s):  
Separated Flows ◽  
Bluff Bodies ◽  
Zonal Method ◽  
Ground Effects

scholarly journals Effect of Side Wind on a Simplified Car Model: Experimental and Numerical Analysis

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Emmanuel Guilmineau ◽  
Francis Chometon
Keyword(s):  
Reynolds Number ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Numerical Data ◽  
Numerical Results ◽  
Separated Flows ◽  
Wind Gust ◽  
Bluff Bodies ◽  
Test Model ◽  
Steady Flows

A prior analysis of the effect of steady cross wind on full size cars or models must be conducted when dealing with transient cross wind gust effects on automobiles. The experimental and numerical tests presented in this paper are performed on the Willy square-back test model. This model is realistic compared with a van-type vehicle; its plane underbody surface is parallel to the ground, and separations are limited to the base for moderated yaw angles. Experiments were carried out in the semi-open test section at the Conservatoire National des Arts et Métiers, and computations were performed at the Ecole Centrale de Nantes (ECN). The ISIS-CFD flow solver, developed by the CFD Department of the Fluid Mechanics Laboratory of ECN, used the incompressible unsteady Reynolds-averaged Navier–Stokes equations. In this paper, the results of experiments obtained at a Reynolds number of 0.9×106 are compared with numerical data at the same Reynolds number for steady flows. In both the experiments and numerical results, the yaw angle varies from 0 deg to 30 deg. The comparison between experimental and numerical results obtained for aerodynamic forces, wall pressures, and total pressure maps shows that the unsteady ISIS-CFD solver correctly reflects the physics of steady three-dimensional separated flows around bluff bodies. This encouraging result allows us to move to a second step dealing with the analysis of unsteady separated flows around the Willy model.

Interaction and acoustics of separated flows from a D-shaped bluff body

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Guangyuan Huang ◽  
Ka Him Seid ◽  
Zhigang Yang ◽  
Randolph Chi Kin Leung
Keyword(s):  
Vortex Shedding ◽  
Bluff Body ◽  
Leading Edge ◽  
Separated Flows ◽  
Pressure Waves ◽  
Bluff Bodies ◽  
Trailing Edge ◽  
Content Type ◽  
Trailing Edges ◽  
Edge Vortex

Purpose For flow around elongated bluff bodies, flow separations would occur over both leading and trailing edges. Interactions between these two separations can be established through acoustic perturbation. In this paper, the flow and the acoustic fields of a D-shaped bluff body (length-to-height ratio L/H = 3.64) are investigated at height-based Reynolds number Re = 23,000 by experimental and numerical methods. The purpose of this paper is to study the acoustic feedback in the interaction of these two separated flows. Design/methodology/approach The flow field is measured by particle image velocimetry, hotwire velocimetry and surface oil flow visualization. The acoustic field is modeled in two dimensions by direct aeroacoustic simulation, which solves the compressible Navier–Stokes equations. The simulation is validated against the experimental results. Findings Separations occur at both the leading and the trailing edges. The leading-edge separation point and the reattaching flow oscillate in accordance with the trailing-edge vortex shedding. Significant pressure waves are generated at the trailing edge by the vortex shedding rather than the leading-edge vortices. Pressure-based cross-correlation analysis is conducted to clarify the effect of the pressure waves on the leading-edge flow structures. Practical implications The understanding of interactions of separated flows over elongated bluff bodies helps to predict aerodynamic drag, structural vibration and noise in engineering applications, such as the aerodynamics of buildings, bridges and road vehicles. Originality/value This paper clarifies the influence of acoustic perturbations in the interaction of separated flows over a D-shaped bluff body. The contribution of the leading- and the trailing-edge vortex in generating acoustic perturbations is investigated as well.

Improvements of a zonal method for the computation of viscous separated flows

1997 ◽  
Author(s):  
V. Saint-Martin ◽  
F. Thivet ◽  
V. Saint-Martin ◽  
F. Thivet
Keyword(s):  
Separated Flows ◽  
Zonal Method

Surface Vorticity Modelling of Separated Flows from Two-Dimensional Bluff Bodies of Arbitrary Shape

1981 ◽  
Vol 23 (1) ◽  
pp. 1-12 ◽  
Author(s):  
R. I. Lewis
Keyword(s):  
Flat Plate ◽  
Arbitrary Shape ◽  
Bluff Body ◽  
The Body ◽  
Separated Flows ◽  
Bluff Bodies ◽  
Two Dimensional ◽  
Vorticity Generation ◽  
Convection Schemes ◽  
Bluff Body Flows

A method is presented for the computation of separated flows past two-dimensional bodies of arbitrary shape. The surface vorticity technique is used to model the body flow and is combined with vorticity generation, shedding, and convection schemes which simulate the separation regime. The method is applied here especially to bluff body flows and illustrative examples have been limited to symmetrical or half plane flows only. An extension of the technique to free streamline flows is described and illustrated by comparison with the classical solution for free streamline separation from a flat plate.

Fundamental Control of Wake Behind Bluff Bodies : A Review

2012 ◽  
Vol 2 (8) ◽  
pp. 134-135
Author(s):  
Dalbir Singh Dalbir Singh ◽  
◽  
M.M. Gaud M.M. Gaud ◽  
Jaswinder Singh Jaswinder Singh
Keyword(s):  
Bluff Bodies
Sign in / Sign up

Export Citation Format

Share Document