Flow Separation Control on a Race Car Wing With Vortex Generators in Ground Effect

2009 ◽  
Vol 131 (12) ◽  
Author(s):  
Yuichi Kuya ◽  
Kenji Takeda ◽  
Xin Zhang ◽  
Scott Beeton ◽  
Ted Pandaleon
Keyword(s):  
Boundary Layer ◽  
Flow Separation ◽  
Large Scale ◽  
Vortex Generator ◽  
Ground Effect ◽  
Vortex Generators ◽  
Separation Control ◽  
Suction Surface ◽  
Flow Separation Control ◽  
Generator Type

Flow separation control using vortex generators on an inverted wing in ground effect is experimentally investigated, and its performance is characterized in terms of forces and pressure distributions over a range of incidence and ride height. Counter-rotating and co-rotating rectangular-vane type vortex generators are tested on the suction surface of the wing. The effect of device height and spacing is investigated. The counter-rotating sub-boundary layer vortex generators and counter-rotating large-scale vortex generators on the wing deliver 23% and 10% improvements in the maximum downforce, respectively, compared with the clean wing, at an incidence of one degree, and delay the onset of the downforce reduction phenomenon. The counter-rotating sub-boundary layer vortex generators exhibit up to 26% improvement in downforce and 10% improvement in aerodynamic efficiency at low ride heights. Chordwise pressure measurement confirms that both counter-rotating vortex generator configurations suppress flow separation, while the co-rotating vortex generators exhibit negligible effectiveness. This work shows that a use of vortex generators, notably of the counter-rotating sub-boundary layer vortex generator type, can be effective at controlling flow separation, with a resultant improvement in downforce for relatively low drag penalty.

Flow Physics of a Race Car Wing With Vortex Generators in Ground Effect

2009 ◽  
Vol 131 (12) ◽  
Author(s):  
Yuichi Kuya ◽  
Kenji Takeda ◽  
Xin Zhang ◽  
Scott Beeton ◽  
Ted Pandaleon
Keyword(s):  
Boundary Layer ◽  
Large Scale ◽  
Vortex Generator ◽  
Ground Effect ◽  
Surface Flow ◽  
Vortex Generators ◽  
Separation Control ◽  
Race Car ◽  
Horseshoe Vortices ◽  
Large Scale Vortex

This paper experimentally investigates the use of vortex generators for separation control on an inverted wing in ground effect using off-surface flow measurements and surface flow visualization. A typical racing car wing geometry is tested in a rolling road wind tunnel over a wide range of incidences and ride heights. Rectangular vane type of sub-boundary layer and large-scale vortex generators are attached to the suction surface, comprising counter-rotating and corotating configurations. The effects of both device height and spacing are examined. The counter-rotating sub-boundary layer vortex generators and counter-rotating large-scale vortex generators suppress the flow separation at the center of each device pair, while the counter-rotating large-scale vortex generators induce horseshoe vortices between each device where the flow is separated. The corotating sub-boundary layer vortex generators tested here show little evidence of separation control. Increasing the spacing of the counter-rotating sublayer vortex generator induces significant horseshoe vortices, comparable to those seen in the counter-rotating large-scale vortex generator case. Wake surveys show significant spanwise variance behind the wing equipped with the counter-rotating large-scale vortex generators, while the counter-rotating sub-boundary layer vortex generator configuration shows a relatively small variance in the spanwise direction. The flow characteristics revealed here suggest that counter-rotating sub-boundary layer vortex generators can provide effective separation control for race car wings in ground effect.

Computational Investigation of a Race Car Wing With Vortex Generators in Ground Effect

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Yuichi Kuya ◽  
Kenji Takeda ◽  
Xin Zhang
Keyword(s):  
Boundary Layer ◽  
Flow Field ◽  
Flow Separation ◽  
Large Scale ◽  
Vortex Generator ◽  
Ground Effect ◽  
Experimental Results ◽  
Vortex Generators ◽  
Flow Physics ◽  
Large Scale Vortex

Vortex generators can be applied to control separation in flows with adverse pressure gradients, such as wings. In this paper, a study using three-dimensional steady computations for an inverted wing with vortex generators in ground effect is described. The main aim is to provide understanding of the flow physics of the vortex generators, and how they affect the overall aerodynamic performance of the wing to complement previous experimental studies of the same configuration. Rectangular vane type sub-boundary layer and large-scale vortex generators are attached to the suction surface of the wing, including both counter-rotating and co-rotating configurations. In order to provide confidence, Reynolds-averaged Navier–Stokes simulations using the Spalart–Allmaras turbulence model are validated against the experimental results regarding force, pressure, and wake characteristics, with the validation exhibiting close agreement with the experimental results. The streamwise friction shows the downwash induced by the generated vortex acts to suppress flow separation. The flow field survey downstream of the vortex generators features breakdown and dominance of the generated vortex in the flow. The vortex generated by the counter-rotating sub-boundary layer vortex generator grows in size and breaks down as it develops downstream, while the vortex generated by the counter-rotating large-scale vortex generator shows high vorticity even further downstream, indicating the persistence of the vortex in the flow. The flow field behind the co-rotating sub-boundary layer vortex generator is dominated by a lateral flow, having the spanwise flow component rather than a swirling flow, and the vortex quickly dissipating as it develops downstream. The results from this paper complement previous experimental measurements by highlighting the flow physics of how vortex generators can help control flow separation for an inverted wing in ground effect, and how critical vortex generator type and size are for its effectiveness.

Reducing Low-Pressure Turbine Stage Blade Count Using Vortex Generator Jet Separation Control

2002 ◽  
Author(s):  
Rolf Sondergaard ◽  
Jeffrey P. Bons ◽  
Matthew Sucher ◽  
Richard B. Rivir
Keyword(s):  
Boundary Layer ◽  
Vortex Generator ◽  
Separation Control ◽  
Surface Boundary ◽  
Freestream Turbulence ◽  
Skew Angle ◽  
Suction Surface ◽  
Simple Boundary ◽  
Design Value ◽  
Vortex Generator Jets

An experimental investigation has been conducted into the feasibility of increasing blade spacing (pitch) at constant chord in a linear turbine cascade. Vortex generator jets (VGJs) located on the suction surface of each blade in the cascade are employed to maintain attached boundary layers despite the increasing tendency to separate due to the increased uncovered turning. Tests were performed at low Mach numbers and at blade Reynolds numbers between 25,000 and 75,000 (based on axial chord and inlet velocity). The vortex generator jets (30 degree injection angle and 90 degree skew angle) were operated with steady flow with momentum blowing ratios between zero and five, and from two spanwise rows of holes located at 45% and 63% axial chord. In the absence of control, pitch-averaged wake losses increase up to 600% as the blade pitch is increased from its design value to twice the design value. With the application of VGJs, these losses were driven down to or below the losses at the design pitch. The effectiveness of VGJs was found to increase modestly with increasing Reynolds number up to the highest value tested, Re = 75,000. The fluid phenomenon responsible for this remarkable range of effectiveness is clearly more than a simple boundary layer transition effect, as boundary layer trips installed on the same blades without VGJ blowing had no beneficial effect on blade losses. Also, tests conducted at elevated levels of freestream turbulence (4% at the cascade inlet) where the suction surface boundary layer is generally turbulent, showed wake loss reduction comparable to tests conducted at the nominal 1% freestream turbulence. For all configurations, blowing from the upstream row had the greatest wake influence. These findings open the possibility that future LPT designs could take advantage of active separation control using integrated VGJs to reduce the turbine part count and stage weight without significant increase in pressure losses.

scholarly journals Plasma Streamwise Vortex Generators for Flow Separation Control on Trucks

2018 ◽  
Vol 100 (4) ◽  
pp. 1101-1109 ◽  
Author(s):  
Julie A. Vernet ◽  
Ramis Örlü ◽  
David Söderblom ◽  
Per Elofsson ◽  
P. Henrik Alfredsson
Keyword(s):  
Flow Separation ◽  
Streamwise Vortex ◽  
Vortex Generators ◽  
Separation Control ◽  
Flow Separation Control

Study on Flow Separation Control by Vortex Generator Jets with Different Parameters

2012 ◽  
Vol 588-589 ◽  
pp. 1786-1789
Author(s):  
Yong Hui Xie ◽  
Zhong Yang Shen ◽  
Tao Fan
Keyword(s):  
Flow Control ◽  
Flow Separation ◽  
Vortex Generator ◽  
Separation Control ◽  
Flow Separation Control ◽  
Profound Influence ◽  
Orthogonal Analysis ◽  
Conical Diffuser ◽  
Flow Charts ◽  
Vortex Generator Jets

In order to investigate the mechanism of flow separation control in conical diffuser by vortex generator jets (VGJs) method, numerical simulations were conducted to discuss the effect of VGJs with different parameters on flow control. The aerodynamic performance in conical diffuser with angle of 14° was tested and analyzed based on Shear-Stress-Transport (SST) simulation. The flow charts at several sections were analyzed, illuminating the formation of complex vortices. Moreover, the effects of 5 VGJs parameters on the diffuser were analyzed by orthogonal analysis. It was shown that the number of jets and the pitch angle of jet showed more profound influence on the flow control by VGJs.

scholarly journals Computational Modelling of Three Different Sub-Boundary Layer Vortex Generators on a Flat Plate

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3107 ◽  
Author(s):  
Ruben Gutierrez-Amo ◽  
Unai Fernandez-Gamiz ◽  
Iñigo Errasti ◽  
Ekaitz Zulueta
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Flow Separation ◽  
Computational Modelling ◽  
Vortex Generator ◽  
Vortex Generators ◽  
Primary Vortex ◽  
Good Efficiency ◽  
Local Boundary ◽  
Passive Flow Control

Flow separation is the source of several problems in a wind turbine including load fluctuations, lift losses, and vibrations. Vortex generators (VGs) are passive flow control devices used to delay flow separation, but their implementation may produce overload drag at the blade section where they are placed. In the current work, a computational model of different geometries of vortex generators placed on a flat plate has been carried out throughout fully meshed computational simulations using Reynolds Averaged Navier-Stokes (RANS) equations performed at a Reynolds number of R e θ = 2600 based on local boundary layer (BL) momentum thickness θ = 2.4 mm. A flow characterization of the wake behind the vortex generator has been done with the aim of evaluating the performance of three vortex generator geometries, namely Rectangular VG, Triangular VG, and Symmetrical VG NACA0012. The location of the primary vortex has been evaluated by the vertical and lateral trajectories and it has been found that for all analyzed VG geometries the primary vortex is developed below the boundary layer thickness δ = 20 mm for a similar vorticity level ( w x m a x ). Two innovative parameters have been developed in the present work for evaluating the vortex size and the vortex strength: Half-Life Surface S 05 and Mean Positive Circulation Γ 05 + . As a result, an assessment of the VG performance has been carried out by all analyzed parameters and the symmetrical vortex generator NACA0012 has provided good efficiency in energy transfer compared with the Rectangular VG.

Design and Scaling of Plasma Streamwise Vortex Generators for Flow Separation Control

AIAA Journal ◽  
2016 ◽  
Vol 54 (11) ◽  
pp. 3397-3408 ◽  
Author(s):  
Christopher L. Kelley ◽  
Thomas C. Corke ◽  
Flint O. Thomas ◽  
Mehul Patel ◽  
Alan B. Cain
Keyword(s):  
Flow Separation ◽  
Streamwise Vortex ◽  
Vortex Generators ◽  
Separation Control ◽  
Flow Separation Control
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