The serpentine plasma actuator represents a broad class of plasma actuator. The actuators vary from the standard type in that their electrode geometry has been modified in to be periodic across its span. [1] [2]
The serpentine plasma actuator represents a broad class of plasma actuator. The actuators vary from the standard type in that their electrode geometry has been modified in to be periodic across its span. [1] [2]
This class of plasma actuators was developed at the Applied Physics Research Group (APRG) at the University of Florida in 2008 by Subrata Roy for the purpose of controlling laminar and turbulent boundary layer flows. Since then, APRG has continued to characterize and develop uses for this class of plasma actuators. Several patents resulted from the early work on serpentine geometry plasma actuators. [3] [4] [5] [6] [7]
In 2013, these actuators started to get broader attention in the scientific press, and several articles were written about these actuators, including articles in AIP's EurekAlert, [8] Inside Science [9] and various blogs. [10] [11]
Serpentine plasma actuators (like other Dielectric Barrier Discharge actuators, i.e. plasma actuators) are able to induce an atmospheric plasma and introduce an electrohydrodynamic body force to a fluid. This body force can be used to implement flow control, and there are a range of potential applications, including drag reduction for aircraft and flow stabilization in combustion chambers. [12]
The important distinction between serpentine plasma actuators and more traditional geometries is that the geometry of the electrodes has been modified in order to be periodic across its span. As the electrode has been made periodic, the resulting plasma and body force are also spanwise periodic. With this spanwise periodicity, three-dimensional flow effects can be induced in the flow, which cannot be done with more traditional plasma actuator geometries.
It is thought that the introduction of three-dimensional flow effects allow for the plasma actuators to apply much greater levels of control authority as they allow for the plasma actuators to project onto a greater range of physical mechanisms (such as boundary layer streaks [13] or secondary instabilities of the Tollmien-Schlichting wave). Recent work indicate that these plasma actuators may have a significant impact on controlling laminar and transitional flows on a flat plate. [14] [15] In addition, the serpentine actuator has been experimentally demonstrated to increase lift, decrease drag and generate controlling rolling moments when applied to aircraft wing geometries. [16]
With the greater level of control authority that these plasma actuators may potentially possess, there is currently research being performed at several labs in the United States [17] [18] and in the United Kingdom [19] looking to apply these actuators for real world applications. Recent numerical work predicted significant turbulent drag reduction by collocating serpentine plasma actuators in a pattern to modify energetic modes of transitional flow. [20]
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The Wingless Electromagnetic Air Vehicle (WEAV) is a heavier than air flight system developed at the University of Florida, funded by the Air Force Office of Scientific Research. The WEAV was invented in 2006 by Dr. Subrata Roy, plasma physicist, aerospace engineering professor at the University of Florida, and has been a subject of several patents. The WEAV employs no moving parts, and combines the aircraft structure, propulsion, energy production and storage, and control subsystems into one integrated system.
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Gamma-Re (γ-Re) transition model is a two equation model used in Computational Fluid Dynamics (CFD) to modify turbulent transport equations to simulate laminar, laminar-to-turbulent and turbulence states in a fluid flow. The Gamma-Re model does not intend to model the physics of the problem but attempts to fit a wide range of experiments and transition methods into its formulation. The transition model calculated an intermittency factor that creates turbulence by slowly introducing turbulent production at the laminar-to-turbulent transition location.
Dwight Barkley is a professor of mathematics at the University of Warwick.
A cyclorotor, cycloidal rotor, cycloidal propeller or cyclogiro, is a fluid propulsion device that converts shaft power into the acceleration of a fluid using a rotating axis perpendicular to the direction of fluid motion. It uses several blades with a spanwise axis parallel to the axis of rotation and perpendicular to the direction of fluid motion. These blades are cyclically pitched twice per revolution to produce force in any direction normal to the axis of rotation. Cyclorotors are used for propulsion, lift, and control on air and water vehicles. An aircraft using cyclorotors as the primary source of lift, propulsion, and control is known as a cyclogyro or cyclocopter. A unique aspect is that it can change the magnitude and direction of thrust without the need of tilting any aircraft structures. The patented application, used on ships with particular actuation mechanisms both mechanical or hydraulic, is named after German company Voith Turbo.
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The MARHy Hypersonic low density Wind Tunnel, located at the ICARE Laboratory in Orléans, France, is a research facility used extensively for fundamental and applied research of fluid dynamic phenomena in rarefied compressible flows. Its name is an acronym for Mach Adaptable Rarefied Hypersonic, and the wind tunnel is recorded under this name in the European portal MERIL.
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Rajat Mittal is a computational fluid dynamicist and a professor of mechanical engineering in the Whiting School of Engineering at Johns Hopkins University. He holds a secondary appointment in the Johns Hopkins University School of Medicine. He is known for his work on immersed boundary methods (IBMs) and applications of these methods to the study of fluid flow problems.