Separation flow control on a generic ground vehicle using steady microjet arrays

Aubrun, Sandrine; McNally, J; Alvi, Farrukh S.; Kourta, Azeddine

doi:10.1007/s00348-011-1132-0

Cited by 79 publications

(36 citation statements)

References 19 publications

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“…A honeycomb grid positioned upstream the wind tunnel collector reduces the turbulence intensity to less than 0.5% [see Aubrun et al (2011) for more details concerning this wind tunnel]. This closed loop wind tunnel has a main test section (2 m × 2 m × 5 m) where the maximum velocity can be equal to 55 m.s -1 .…”

Section: The Wind Tunnel and The Modelmentioning

confidence: 99%

Aerodynamic characterisation of a square back bluff body flow

Lahaye

Leroy

Kourta

2014

IJAD

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International audienceThis article deals with the flow characterisation around a square back Ahmed body. Results of time-averaged and instantaneous flow characteristics are compared to the literature. All the results presented in this article were obtained when the Reynolds number independency of the drag coefficient was reached. The first part of the study focuses on time-averaged results. The turbulent boundary layer on the roof of the model has been characterised and mean flow topology is investigated thanks to particle imaging velocimetry and pressure measurements. The second part of the paper is dedicated to the characterisation of the vortex shedding in the wake using hot wire anemometry. The phase difference of vortex shedding between two edges, the vortex pairing in the shear layers and the pumping effect are tackled

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Section: The Wind Tunnel and The Modelmentioning

confidence: 99%

Aerodynamic characterisation of a square back bluff body flow

Lahaye

Leroy

Kourta

2014

IJAD

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“…Most of the studies are dedicated to manipulate the wake by forcing the separated shear layer. These include the application of steady blowing or suction of air flow (Rouméas et al 2009;Aubrun et al 2011) or unsteady synthetic or pulsed jets (Glezer et al 2005;Rouméas et al 2009;Park et al 2013;Joseph et al 2013;Oxlade et al 2015;Seifert et al 2015) on the separation trailing edges. AFC can be combined with passive deflected surfaces to gain additional base pressure recovery by enhancing the shear layer deflection (Englar 2001(Englar , 2004Schmidt et al 2015;Barros et al 2016b).…”

Section: Introductionmentioning

confidence: 99%

Drag reduction of a car model by linear genetic programming control

Noack

Cordier

et al. 2017

Exp Fluids

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We investigate open-and closed-loop active control for aerodynamic drag reduction of a car model. Turbulent flow around a blunt-edged Ahmed body is examined at Re H ≈ 3 × 10 5 based on body height. The actuation is performed with pulsed jets at all trailing edges combined with a Coanda deflection surface. The flow is monitored with pressure sensors distributed at the rear side. We apply a model-free control strategy building on Dracopoulos & Kent (1997) and Gautier et al. (2015). The optimized control laws comprise periodic forcing, multi-frequency forcing and sensor-based feedback including also time-history information feedback and combination thereof. Key enabler is linear genetic programming as simple and efficient framework for multiple inputs (actuators) and multiple outputs (sensors). The proposed linear genetic programming control can select the best open-or closed-loop control in an unsupervised manner. Approximately 33% base pressure recovery associated with 22% drag reduction is achieved in all considered classes of control laws. Intriguingly, the feedback actuation emulates periodic high-frequency forcing by selecting one pressure sensor in the optimal control law. Our control strategy is, in principle, applicable to all multiple actuators and sensors experiments.

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“…Experimental studies of Lehugeur et al (2010) showed that the control using the steady suction or blowing normal to the lateral face of the Ahmed body change significantly the topology of the vortex core and reduce the drag. Aubrun et al (2011) have applied an actuation consisting on steady micro-jet array placed 6mm downstream of the separation line between the roof and the slanted rear window. This actuation has reduced the drag coefficient by 9 to 14 % and the lift coefficient up to 42%.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Flow Control on Bluff Body using Piezoelectric Actuators

Tounsi¹,

Mestiri²,

Keirsbulck³

et al. 2016

JAFM

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Active flow control is experimentally investigated on a car-type bluff body. The actuation is based on a synthetic jet actuator placed at the top of the Ahmed body rear window. In the present paper, a synthetic jet characterization is presented, the frequencies and the optimal amplitudes with regard to the spatial evolution are analyzed. All the measurements are carried out in a wind tunnel at Reynolds numbers based on the body length between 10 6 and 3 × 10 6 . The bluff body shows a maximum drag reduction of 10% when optimal control is applied. Independent effect of the reduced frequency and the momentum coefficient actuation parameters on the drag reduction are also detailed in the present paper. This reduction induces changes in the flow field due to the piezoelectric actuation. The flow topology modification is investigated via particle image velocimetry measurements in order to estimate the flow response to a local excitation and to understand the mechanism involved in the aerodynamic drag control.

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Separation flow control on a generic ground vehicle using steady microjet arrays

Cited by 79 publications

References 19 publications

Aerodynamic characterisation of a square back bluff body flow

Aerodynamic characterisation of a square back bluff body flow

Drag reduction of a car model by linear genetic programming control

Experimental Study of Flow Control on Bluff Body using Piezoelectric Actuators

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