Delay of natural transition with dielectric barrier discharges

Duchmann, Alexander; Grundmann, Sven; Tropea, Cameron

doi:10.1007/s00348-013-1461-2

Cited by 23 publications

(8 citation statements)

References 27 publications

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“…It should be noted, however, that the streaks can also promote transition by enhancing the secondary instability of Tollmien-Schlichting waves (Liu, Zaki & Durbin 2008a,b). More recent attempts to delay transition include the work by Duchmann, Grundmann & Tropea (2013). They demonstrated the effectiveness of dielectric barrier discharges to increase the Reynolds number at the onset of natural transition by approximately 10 %.…”

Section: Reduction Of Turbulent Drag By Unsteady Forcingmentioning

confidence: 99%

The influence of harmonic wall motion on transitional boundary layers

Hack

Zaki

2014

J. Fluid Mech.

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The influence of harmonic spanwise wall motion on bypass transition in boundary layers is investigated using direct numerical simulations. It is shown that the appropriate choice of the forcing parameters can achieve a substantial stabilization of the laminar flow regime. However, an increase of the forcing amplitude or period beyond their optimal values diminishes the stabilizing effect, and leads to breakdown upstream of the unforced case. For the optimal wall-oscillation parameters, the reduction in propulsion power substantially outweighs the power requirement of the forcing. The mechanism of transition delay is examined in detail. Analysis of the pre-transitional streaks shows that the wall oscillation substantially reduces their average amplitude, and eliminates the most energetic streaks. As a result, the secondary instabilities that precede breakdown to turbulence are substantially weakened – an effect demonstrated by linear stability analyses of flow fields from direct numerical simulations. The outcome is transition delay owing to a significant reduction in the frequency of occurrence of turbulent spots and a downstream shift in their average inception location. Finally, it is shown that the efficiency of the forcing can be further improved by replacing the sinusoidal time dependence of the wall oscillation with a square wave.

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Section: Reduction Of Turbulent Drag By Unsteady Forcingmentioning

confidence: 99%

The influence of harmonic wall motion on transitional boundary layers

Hack

Zaki

2014

J. Fluid Mech.

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“…For ns-DBD plasma actuators, they usually induce an ultrafast gas heating mechanism eventually leading to the generation of a shockwave [19][20][21][22] . The plasma discharge generates an ionic airflow along the surface of the dielectric layer, which has been widely used for flow manipulation such as separation control on airfoils [23][24][25] and suppression of boundary layer transition 26,27 . Therefore, for the application of DBD plasma actuators on aircraft, they are usually designed to be located at the regions where the aerodynamic characteristics alter greatly as incoming flow changes, e.g., airfoil leading edge, duct lip of aero-engines, etc.…”

Section: Introductionmentioning

confidence: 99%

A Comparison Study on AC-DBD Plasma and Electrical Heating for Aircraft Icing Mitigation

Liu

Kolbakir

2018

2018 AIAA Aerospace Sciences Meeting

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A comparison study of utilizing thermal effects of a Dielectric-Barrier-Discharge (DBD) plasma actuator and a conventional electrical film heater for aircraft icing mitigation was performed in an Icing Research Tunnel available at Iowa State University (i.e., ISU -IRT). A NACA0012 airfoil/wing model embedded with an AC-DBD plasma actuator and a conventional electrical film heater over the airfoil surface was tested under a typical aircraft icing condition. While a high-speed imaging system was used to record the dynamic ice accretion and transient surface water transport processes over the airfoil surface, an infrared (IR) thermal imaging system was also utilized to map the corresponding surface temperature distributions over the airfoil surface simultaneously to quantify the unsteady heat transfer and phase changing process over the ice accreting airfoil surface. It was found that, for the same input power, the AC-DBD plasma actuator and the electrical film heater showed almost the equivalent effectiveness in preventing ice accretion over the airfoil surface. With the same total power input, further optimization of the AC-DBD plasma actuator with a duty-cycle modulation was found to have a better anti-/de-icing performance, in comparison to the conventional electrical film heater. The findings derived from the present study demonstrated the potential of a new class of anti-/de-icing strategy by leveraging the thermal effects of DBD plasma actuators for aircraft in-flight icing mitigation.

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“…More recently, Choi & Kim (2018) performed experiments on ring-type plasma actuators, which act as virtual roughness elements, and found that the body force leads to a wall-normal jet. In flow control, the body force induced by the DBD plasma actuators have been used for the delay of classic (Grundmann & Tropea 2008; Riherd & Roy 2013; Duchmann, Grundmann & Tropea 2014) and bypass (Hanson et al. 2010; Riherd & Roy 2014; Bade et al.…”

Section: Introductionmentioning

confidence: 99%

Bypass transition in a boundary layer flow induced by plasma actuators

et al. 2021

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Bypass transition in flow over a flat plate triggered by a pair of dielectric-barrier-discharge plasma actuators mounted on the plate surface and aligned in the streamwise direction is investigated. A four-species plasma–fluid model is used to model the electrohydrodynamic force generated by the plasma actuation. A pair of counter-rotating streamwise vortices is created downstream of the actuators, leading to the formation of a high-speed streak in the centre and two low-speed streaks on each side. As the length of actuators increases, more momentum is added to the boundary layer and eventually a turbulent wedge is generated at an almost fixed location. With large spanwise distance between the actuators (wide layout), direct numerical simulations indicate that the low-speed streaks on both sides lose secondary stability via an inclined varicose-like mode simultaneously, leaving a symmetric perturbation pattern with respect to the centre of the actuators. Further downstream, the perturbations are tilted by the mean shear of the high- and low-speed streaks and consequently a ‘W’-shaped pattern is observed. When the pair of plasma actuators is placed closer (narrow layout) in the spanwise direction, the mean shear in the centre becomes stronger and secondary instability first occurs on the high-speed streak with an asymmetric pattern. Inclined varicose-like and sinuous-like instabilities coexist in the following breakdown of the negative streaks on the side and the perturbations remain asymmetric with respect to the centre. Here the tilting of disturbances is dominated by the mean shear in the centre and the perturbations display a ‘V’ shape. Linear analysis techniques, including biglobal stability and transient growth, are performed to further examine the fluid physics; the aforementioned phenomena at narrow and wide layouts, such as the secondary instabilities, the ‘V’ and ‘W’ shapes, and the symmetric and asymmetric breakdown, are all observed.

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Delay of natural transition with dielectric barrier discharges

Cited by 23 publications

References 27 publications

The influence of harmonic wall motion on transitional boundary layers

The influence of harmonic wall motion on transitional boundary layers

A Comparison Study on AC-DBD Plasma and Electrical Heating for Aircraft Icing Mitigation

Bypass transition in a boundary layer flow induced by plasma actuators

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