Drag and lift reduction of a 3D bluff body using flaps

Beaudoin, Jean-François; Aider, Jean-Luc

doi:10.1007/s00348-007-0392-1

Cited by 128 publications

(74 citation statements)

References 16 publications

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“…1999;Spohn & Gillieron 2002;Lienhart & Becker 2003). Recently, the model has been subjected to intensive research for the pursuit of flow control methods capable of reducing the aerodynamic drag on the model, both passive control (Beaudoin & Aider 2008;Krajnović 2013), and active control (Brunn et al 2008;Pastoor et al 2008;Krajnović & Fernandes 2011;Aider et al 2010). In the present study, we focus on the square-back variant of the Ahmed body, which is essentially a bluff body with curved front edges placed in the proximity of ground.…”

Section: Introductionmentioning

confidence: 99%

On the need for a nonlinear subscale turbulence term in POD models as exemplified for a high-Reynolds-number flow over an Ahmed body

et al. 2014

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We investigate a hierarchy of eddy-viscosity terms in POD Galerkin models to account for a large fraction of unresolved fluctuation energy. These Galerkin methods are applied to Large Eddy Simulation data for a flow around the vehicle-like bluff body called Ahmed body. This flow has three challenges for any reduced-order model: a high Reynolds number, coherent structures with broadband frequency dynamics, and meta-stable asymmetric base flow states. The Galerkin models are found to be most accurate with modal eddy viscosities as proposed by Rempfer & Fasel (1994). Robustness of the model solution with respect to initial conditions, eddy viscosity values and model order is only achieved for state-dependent eddy viscosities as proposed by Noack, Morzyński & Tadmor (2011). Only the POD system with state-dependent modal eddy viscosities can address all challenges of the flow characteristics. All parameters are analytically derived from the Navier-Stokes based balance equations with the available data. We arrive at simple general guidelines for robust and accurate POD models which can be expected to hold for a large class of turbulent flows.

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Section: Introductionmentioning

confidence: 99%

On the need for a nonlinear subscale turbulence term in POD models as exemplified for a high-Reynolds-number flow over an Ahmed body

et al. 2014

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“…This can be achieved through passive optimization, for example geometry changes, vortex generators, flaps, and surface roughness, or using active control, for example, suction, blowing, oscillated suction and blowing, moveable vortex generators or flaps [2][3][4][5][6][7][8][9][10][11]. Active flow control is an attractive option because of the potential freedom it allows for vehicle styling as all that is required externally is the jet orifices.…”

Section: Introductionmentioning

confidence: 99%

Influence of Short Rear End tapers on the Base Pressure of a Simplified Vehicle.

Perry

Passmore

Finney

2015

SAE Int. J. Passeng. Cars - Mech. Syst.

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Author, co-author (Do NOT enter this information. It will be pulled from participant tab in MyTechZone)Affiliation (Do NOT enter this information. It will be pulled from participant tab in MyTechZone) AbstractThis paper looks into the effect on base pressure of applying a high aspect ratio chamfer to all edges of a simplified squareback model (the Windsor model). The effects are investigated using force and moment measurements along with surface pressure measurements on the slanted surface and vertical base. The work forms part of a larger study to develop understanding of the mechanisms that influence overall base pressure and hence the resulting aerodynamic drag.A short slant (approx. 4% of model length) was applied to the trailing edges of the simplified vehicle model, representing the small rear end optimisation typical of many real vehicle geometries. Two experiments were performed: the first applied a chamfer at varying angles to the top and bottom edges; the second test looked at the same chamfer angle applied to the sides of the model geometry while the top and bottom angle remained square. The changes in drag are discussed and explained in the context of the base pressures and area weighted pressure coefficients.

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“…Ouyang et al 's [1] research verified that the change of the tail edge angle is an effective way to optimize the lift and drag force. One of the passive control methods is to fix flaps to the tail edges [2]. Fixing flaps to different edges arouses different changes of wake flow, which generates different influences to the lift and drag force.…”

Section: Introductionmentioning

confidence: 99%

A New Method to Optimize the Wake Flow of a Vehicle: The Leading Edge Rotating Cylinder

Shao

Yao

Zhang

et al. 2017

Mathematical Problems in Engineering

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The wake flow of a vehicle significantly influences its aerodynamic performance and the stability during high-speed drive. Therefore, optimization of the vehicle wake flow is an effective way to improve its aerodynamic performance and further improve the handling stability and fuel economy. In this paper, a new method, the leading edge rotating cylinder, is used to optimize the wake flow of a vehicle. According to the results of simulations, this method can reduce the pressure drag, increase the negative lift force, and strengthen the stability of the vehicle under crosswind. Furthermore, this method optimizes not only the wake flow of the vehicle with rotating cylinders but also the interactive vehicles in the driving route in overtaking maneuvers or platoon driving. In conclusion, this method effectively optimizes the flow fields around the vehicles, and it significantly helps to improve the handling stability and fuel economy of the vehicle.

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Drag and lift reduction of a 3D bluff body using flaps

Cited by 128 publications

References 16 publications

On the need for a nonlinear subscale turbulence term in POD models as exemplified for a high-Reynolds-number flow over an Ahmed body

On the need for a nonlinear subscale turbulence term in POD models as exemplified for a high-Reynolds-number flow over an Ahmed body

Influence of Short Rear End tapers on the Base Pressure of a Simplified Vehicle.

A New Method to Optimize the Wake Flow of a Vehicle: The Leading Edge Rotating Cylinder

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