Using Inherent Flow Instabilities Mo Samimy Gas Dynamics and - - PowerPoint PPT Presentation

Plasma Actuator Based Flow Control Using Inherent Flow Instabilities

Mo Samimy Gas Dynamics and Turbulence Laboratory Aeronautical and Astronautical Research Laboratories Department of Mechanical and Aerospace Engineering

Workshop on AP WIP for ET, FC, and MP Princeton, August 2011

Acknowledgements

• Igor Adamovich and Datta Gaitonde
• Martin Kearney-Fischer, Ani Sinha, Jin-Hwa Kim, Nathan

Webb, Chris Clifford, Jesse Little, Chris Rethmel, Casey Hahn, and Mike Crawley

• NASA, AFOSR, AFRL/WPAFB, ONR, and NAVAIR
• Dick Miles for organizing the workshop

Flow Control Exploiting Natural Flow Instabilities Using Plasma Actuators

• There are many classes of high-speed and high Reynolds number

flow of interest to DoD with well known instabilities

• Excitation of these instabilities using plasma actuators offers a

great opportunity for effective and efficient flow control

• A few examples are:

– SBLI (in scramjet and in supersonic aircraft inlet) – Mixing/combustion (in tactical aircraft exhaust and in scramjet engine) – Cavity flows (in weapons bay and landing gear) – Flow separation (in fixed wing or rotary aircraft) – Jet noise (in tactical and commercial aircraft)

Flow Control Exploiting Natural Flow Instabilities Using Plasma Actuators

• The three selected problems for demonstration are:

– Jet noise – Shock/boundary layer interactions (SBLI) – Flow separation over a wing/an airfoil (flow separation)

• We have used two classes of plasma actuators to generate

perturbations of desired frequency and mode

– Localized Arc Filament Plasma Actuators (LAFPAs) for jet noise and SBLI – Nano Second pulse driven Dielectric Barrier Discharge (NS-DBD) actuators for flow separation

Jet Noise and Jet Instabilities

• It has been known that:

– A jet contains several instabilities and amplifies perturbations

• ver a range of frequencies and modes

– The amplified perturbations grow into large-scale structures, dynamics of which are responsible for the peak far-field noise

• There are significant clues that dynamics of some

structures are less efficient in generating far-field noise

• We seek to selectively enhance the less efficient structures

using plasma actuators to reduce the far-field noise

PIV measurements - jet width at half centerline velocity for Mach 0.9 jet (ReD=0.61x106) forced at m = 0 using 8 LAFPAs

Initial Shear Layer and Jet Column Instabilities

Forcing Strouhal Number (StDF=fD/Uj)

Control Effects on Flow Structures (M=1.3; ReD=1.07x106; m=1)

StDF=0.33 StDF=0.52 Galilean streamlines superimposed on Q-criterion contours

Control Effects on Flow Structures (M=1.3; ReD=1.07x106; m=1)

StDF=0.33 StDF=1.05 Galilean streamlines superimposed on Q-criterion contours

Control Effects on Far-Field Noise (OASPL) – (M=1.3; m=3 & TTR = 2)

Localized Arc Filament Plasma Actuators (LAFPAs)

• A pair of electrodes (1 mm dia. tungsten)

connected to a high voltage (~kV) or a low voltage power supply with a transformer constitutes a LAFPA

• A LAFPA provides localized high amplitude

heating (arc filament cross section is ~1-2 mm2)

• We are using 8 actuators with any prescribed

frequency, phase, and duty cycle

– Frequencies from 0 to 200 kHz – In jet, with 8 actuators could force several azimuthal modes (m=0-3 & ±1/±2/±4)

• Power requirement is approximately

20-40 W per actuator so it is scalable

• LAFPAs provide opportunities for flow control

and diagnostics in variety of flows

Flow

Actuator

Shock/Boundary Layer Interaction

• Shock wave/boundary layer interactions (SWBLIs) are

prevalent in supersonic/hypersonic flows and the cause of unsteady high pressure and thermal loading

• While the unsteady nature of the interaction has been

recognized for quite sometime, its relatively coherent nature has been recognized more recently, which provides an

• pportunity for active control

11

Touber and Sandham (2009)

Schlieren Image – Mach 2.3 – Variable-Angle Wedge

Surface Pressure PSD in the Interaction Region Mach 2.3; 9° Wedge

Streamwise Mean Velocity Profiles in Interaction Region

(actuators upstream, but measurement plane within SWBLI region)

Airfoil Lift Characterization Without Flow Control

Stall angle ~ 13

With NS-DBD Control (Re = 1.15x106, α = 18°)

• Mach number of 0.26, typical takeoff

and landing speed

Concluding Remarks

• Over the past 10 years or so, there has been tremendous

progress on the development and use of plasma actuators for flow control

• This is a multi-disciplinary field requiring larger efforts

bringing together experimental and computational fluid dynamics and plasma dynamics communities

• The field also requires larger focused efforts to scale up the

technology

References

• Samimy, M., Kim, J.-H., Kastner, J., Adamovich, I., and Utkin, Y., “Active Control of High

Speed and High Reynolds Number Jets Using Plasma Actuators,” Journal of Fluid Mechanics, Vol. 578, pp. 305-330, May 2007.

• Utkin, Y., Keshav, S., Kim, J.-H., Kastner, J., Adamovich, I., and Samimy, M., “Use of

Localized Arc Filament Plasma Actuators for High Speed Jet Control,” Journal of Physics D: Applied Physics, Vol. 40, pp. 685-694, February 2007.

• Samimy, M., Kim, J.-H., Kearney-Fischer, M., and Sinha, A., “Acoustic and Flow Fields of

an Excited High Reynolds Number Axisymmetric Perfectly-Expanded Supersonic Jet,” Journal of Fluid Mechanics, Vol. 656, August 2010, pp. 507-529.

• Kearney-Fischer, M., Kim, J.-H., and Samimy, M., “A Study of Mach Wave Radiation Using

Active Control,” Journal of Fluid Mechanics, Vol. 681, August 2011, pp. 261-292.

• Kim, J.-H, Kearney-Fischer, M., Samimy, M., and Gogineni, S., “Far-field Noise Control in

Supersonic Jets Using Conical and Contoured Nozzles,” ASME Journal of Engineering for Gas Turbine and Power, Vol. 133, August 2011, pp 081201-1 to 081201-9.

• Webb, N., Clifford, C., and Samimy, M., “Preliminary Results on Control of Shock

Wave/Boundary Layer Interaction Using Plasma Actuators,” 41st AIAA Fluid Dynamics Conference in Hawaii, AIAA-2011-3426.

• Rethmel, C., Little, J., Takashima, K., Nishihara, M., Adamovich, I., and Samimy, M., “Flow

Separation Control over and Airfoil with Nanosecond Pulse Driven DBD Plasma Actuators,” AIAA Paper No. 2011-487, January 2011.

• Takashima K, Zuzeek Y, Lempert WR, Adamovich IV (2010) Characterization of Surface

Dielectric Barrier Discharge Plasma Sustained by Repetitive Nanosecond Pulses. AIAA Paper 2010-4764