0
Research Papers: Fundamental Issues and Canonical Flows

Circular Cylinder Drag Reduction By Three-Electrode Plasma Symmetric Forcing

[+] Author and Article Information
Juan D'Adamo

CONICET,
Facultad de Ingenieria,
Universidad de Buenos Aires,
Buenos Aires C1063ACV, Argentina
e-mail: jdadamo@fi.uba.ar

Leandro Leonardo, Federico Castro, Roberto Sosa, Guillermo Artana

CONICET,
Facultad de Ingenieria,
Universidad de Buenos Aires,
Buenos Aires C1063ACV, Argentina

Thomas Duriez

CONICET,
Facultad de Ingenieria,
Universidad de Buenos Aires,
Buenos Aires C1063ACV, Argentina;
Laboratorio de Microfluídica,
Universidad de la afarina Mercante,
Marina Mercante C1034ACO, Argentina

1Corresponding author.

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received August 14, 2016; final manuscript received January 23, 2017; published online April 20, 2017. Assoc. Editor: Shizhi Qian.

J. Fluids Eng 139(6), 061202 (Apr 20, 2017) (14 pages) Paper No: FE-16-1514; doi: 10.1115/1.4035947 History: Received August 14, 2016; Revised January 23, 2017

This study reports an efficient reduction of the drag exerted by a flow on a cylinder when the former is forced with a plasma actuator. A three-electrode plasma device (TED) disposed on the surface of the body is considered, and the effect of the actuation frequency and amplitude is studied. Particle image velocimetry (PIV) measurements provided a detailed information that was processed to obtain the time-averaged drag force and to compare the performances of TED actuator and the canonical dielectric discharge barrier actuator. For the Reynolds number considered (Re = 5500), excitations with the TED actuator were more efficient, achieving drag reductions that attained values close to 40% with high net energy savings. The reduction of coherent structures using the instantaneous vorticity fields and a clustering technique allowed us to gain insight into the physical mechanisms involved in these phenomena. This highlights that the symmetrical forcing of the wake flow at its resonant frequency with the TED promotes symmetrical vorticity patterns which favor drag reductions.

Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Different implementations of plasma discharge devices: (a) sliding discharge, (b) DBD, (c) serial DBD, and (d) three electrode discharge

Grahic Jump Location
Fig. 2

Scheme of the region analyzed with PIV

Grahic Jump Location
Fig. 3

(a) Schematic and detail of the electrohydrodynamic (EHD) actuator, electric circuit with the electrodes flush-mounted and (b) typical burst input waveform applied to the electrodes

Grahic Jump Location
Fig. 4

Electrical power consumption for TED actuator (squares). Dotted line represents DBD actuator consumption.

Grahic Jump Location
Fig. 5

(a) Wake velocity profiles for nonforced and forced flow at x = 4 and (b) normalized momentum flux produced by TED actuators

Grahic Jump Location
Fig. 6

Contour levels for the time-averaged y-component of pressure gradient 〈∂p/∂y〉 for nonforced flow (a) and under TED VDC= −11 kV, f+=1 (b). Dashed lines show control volume boundaries.

Grahic Jump Location
Fig. 7

Drag coefficient estimation for the unforced case (solid line), DBD and TED enhanced through stationary forcing mode. Electrode A DC voltage is decreased from 0 to −11 kV so nondimensional momentum Cμ increases monotonically with respect to VDC.

Grahic Jump Location
Fig. 8

Drag coefficient estimation for nonforced case, DBD and TED enhanced (−11 kV)) through harmonic forcing at DC = 50%. Forcing frequencies f+=ff/f0 are from 0.2 up to 5.0, measurements have been refined around the minimum at f+=1.

Grahic Jump Location
Fig. 9

(a) Electric power PTED, drag dissipated power PD and total lost power PTED+PD as duty cycle DC rises. Values are normalized with the power associated to drag forces when no actuation is imposed PD0. A maximum 27% net energy saving can be achieved for a 19% duty cycle, still corresponding to a 40% drag reduction. (b) Energy efficiency versus duty cycle for TED actuation. In both figures Re = 5500 and f+=1.

Grahic Jump Location
Fig. 10

(a) Mean flow streamlines and velocity modulus contours for Re = 5500, (b) DBD forcing at f+=1, DC=50%, and (c) TED forcing at f+=1, DC=50%

Grahic Jump Location
Fig. 11

Time-averaged velocity moments profiles: (a) 〈ux〉, (b) 〈u′y2〉1/2, (c) 〈u′x2〉1/2, and (d) 〈u′xu′y〉. The profiles are taken at positions x/D∈[1,2,3,4,5].

Grahic Jump Location
Fig. 12

Global mode shape modification under TED actuation for different forcing frequencies. The black thick line stands for global mode of the nonforced case.

Grahic Jump Location
Fig. 13

For the nonforced flow, clusters portrait the vortex shedding dynamics from vorticity contour lines (solid for positive values and dashed for negative values) within one period. The number of snapshots involved is shown in each subplot; initial clusters are placed after the last one to complete the loop.

Grahic Jump Location
Fig. 14

(a) Phase portrait from singular value decomposition of the vorticity clusters, three modes are enough to describe the dynamics of vortex shedding. A limit cycle attractor is emphasized by a minimum distance plane to the data, and a close curve that connects the centroids. (b) The result is clearer after a 2D projection onto the plane.

Grahic Jump Location
Fig. 15

Eleven clusters portrait the vortex shedding dynamics from vorticity contour lines within one period. The number of snapshots involved is shown in each subplot; initial clusters are placed after the last one to complete a loop. We observe two distinct regimes which correspond with BvK-like vortex shedding and two vortex sheets produced by DBD momentum injection.

Grahic Jump Location
Fig. 16

Idem Fig. 15 for TED momentum injection

Grahic Jump Location
Fig. 17

Phase portrait from singular value decomposition of the vorticity clusters, three modes are enough to describe the dynamics of vortex shedding modified by actuation. Regimes identified in Fig. 16 correspond to the outer (BvK-like regime) or inner (TED momentum injection) phase space regions.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In