Transportation of goods and people involves moving objects through air, which leads to a force opposing motion. This drag force can account for more than 60% of power consumed by a ground vehicle, such as a car or truck, at highway speeds. This paper studies drag reduction on the 25-deg Ahmed generic vehicle model with quasi-steady blowing at the roof–slant interface using a spanwise array of fluidic oscillators. A fluidic oscillator is a simple device that converts a steady pressure input into a spatially oscillating jet. Drag reduction near 7% was attributed to separation control on the rear slant surface. Particle image velocimetry (PIV) and pressure taps were used to characterize the flow structure changes behind the model. Oil flow visualization was used to understand the mechanism behind oscillator effectiveness. An energy analysis suggests that this method may be viable from a flow energy perspective.

References

References
1.
Hucho
,
W.-H.
,
1998
,
Aerodynamics of Road Vehicles: From Fluid Mechanics to Vehicle Engineering
,
4th ed.
,
W.-H.
Hucho
, ed.,
SAE International
,
Warrendale, PA
, Vol.
R-177
, Chap. 4.
2.
Littlewood
,
R. P.
, and
Passmore
,
M. A.
,
2012
, “
Aerodynamic Drag Reduction of a Simplified Squareback Vehicle Using Steady Blowing
,”
Exp. Fluids
,
53
(
2
), pp.
519
529
.10.1007/s00348-012-1306-4
3.
Gregory
,
J. W.
,
Sullivan
,
J. P.
,
Raman
,
G.
, and
Raghu
,
S.
,
2007
, “
Characterization of a Microfluidic Oscillator
,”
AIAA J.
,
45
(
3
), pp.
568
576
.10.2514/1.26127
4.
Gregory
,
J. W.
, and
Tomac
,
M. N.
,
2013
, “
A Review of Fluidic Oscillator Development and Application for Flow Control
,”
AIAA
Paper No. 2013-2474.10.1115/2013-2474
5.
Tomac
,
M. N.
,
2013
, “
Internal Fluid Dynamics and Frequency Characteristics of Feedback-Free Fluidic Oscillators
,” Ph.D. thesis, Ohio State University, Columbus, OH.
6.
Roumeas
,
M.
,
Gillieron
,
P.
, and
Kourta
,
A.
,
2009
, “
Drag Reduction by Flow Separation Control on a Car After Body
,”
Int. J. Numer. Methods Fluids
,
60
(
11
), pp.
1222
1240
.10.1002/fld.1930
7.
Conan
,
B.
,
Anthoine
,
J.
, and
Planquart
,
P.
,
2011
, “
Experimental Aerodynamic Study of a Car-Type Bluff Body
,”
Exp. Fluids
,
50
(
5
), pp.
1273
1284
.10.1007/s00348-010-0992-z
8.
Ahmed
,
S. R.
,
Ramm
,
G.
, and
Faltin
,
G.
,
1984
, “
Some Salient Features of the Time Averaged Vehicle Wake
,” SAE Technical Paper No. 840300.
9.
Gilliéron
,
P.
,
Leroy
,
A.
,
Aubrun
,
S.
, and
Audier
,
P.
,
2010
, “
Influence of the Slant Angle of 3D Bluff Bodies on Longitudinal Vortex Formation
,”
ASME J. Fluids Eng.
,
132
(
5
), p.
051104
.10.1115/1.4001450
10.
Joseph
,
P.
,
Amandolèse
,
X.
, and
Aider
,
J.-L.
,
2012
, “
Drag Reduction on the 25° Slant Angle Ahmed Reference Body Using Pulsed Jets
,”
Exp. Fluids
,
52
(
5
), pp.
1169
1185
.10.1007/s00348-011-1245-5
11.
Johari
,
H.
, and
Rixon
,
G. S.
,
2003
, “
Effects of Pulsing on a Vortex Generator Jet
,”
AIAA J.
,
41
(
12
), pp.
2309
2315
.10.2514/2.6836
12.
Woszidlo
,
R.
,
Stumper
,
T.
,
Nayeri
,
C. N.
, and
Paschereit
,
C. O.
,
2014
, “
Experimental Study of Bluff Body Drag Reduction With Fluidic Oscillators
,”
AIAA
Paper No. 2014-0403.10.1115/2014-0403
13.
Pujals
,
G.
,
Depardon
,
S.
, and
Cossu
,
C.
,
2010
, “
Drag Reduction of a 3D Bluff Body Using Coherent Streamwise Streaks
,”
Exp. Fluids
,
49
(
5
), pp.
1085
1094
.10.1007/s00348-010-0857-5
14.
Krajnovic
,
S.
,
2014
, “
Large Eddy Simulation Exploration of Passive Flow Control Around an Ahmed Body
,”
ASME J. Fluids Eng.
,
136
(
12
), p.
121103
.10.1115/1.4027221
15.
Metka
,
M.
,
2013
, “
Flow Control on the Ahmed Body Vehicle Model Using Fluidic Oscillators
,”
International Mechanical Engineering Congress and Exposition
, Volume 7B: Fluids Engineering Systems and Technologies Conference, San Diego, CA, No. IMECE2013-67343.
16.
Zhou
,
J.
,
Adrian
,
R. J.
,
Balachandar
,
S.
, and
Kendall
,
T. M.
,
1999
, “
Mechanisms for Generating Coherent Packets of Hairpin Vortices in Channel Flow
,”
J. Fluid Mech.
,
387
(
1
), pp.
353
396
.10.1017/S002211209900467X
17.
Park
,
H.
,
Lee
,
D.
,
Jeon
,
W.-P.
,
Hahn
,
S.
,
Kim
,
J.
,
Kim
,
J.
,
Choi
,
J.
, and
Choi
,
H.
,
2006
, “
Drag Reduction in Flow Over a Two-Dimensional Bluff Body With a Blunt Trailing Edge Using a New Passive Device
,”
J. Fluid Mech.
,
563
(
1
), pp.
389
414
.10.1017/S0022112006001364
18.
Beaudoin
,
J.-F.
, and
Aider
,
J.-L.
,
2008
, “
Drag and Lift Reduction of a 3D Bluff Body Using Flaps
,”
Exp. Fluids
,
44
(
4
), pp.
491
501
.10.1007/s00348-007-0392-1
You do not currently have access to this content.