Vortical Flow Control over Delta Wings with Different Sweep Back Angles Using DBD Plasma Actuator

2010 ◽  
Author(s):  
Dkong Kwak ◽  
Robert Nelson
Keyword(s):  
Flow Control ◽  
Plasma Actuator ◽  
Vortical Flow ◽  
Dbd Plasma ◽  
Delta Wings

scholarly journals Coherent structures induced by dielectric barrier discharge plasma actuator

2017 ◽  
Vol 31 (32) ◽  
pp. 1850038 ◽  
Author(s):  
Xin Zhang ◽  
Huaxing Li ◽  
Kwing So Choi ◽  
Longfei Song
Keyword(s):  
Flow Control ◽  
Dielectric Barrier Discharge ◽  
Coherent Structures ◽  
High Speed ◽  
Barrier Discharge ◽  
Plasma Actuator ◽  
Dbd Plasma ◽  
Peak Voltage ◽  
Dielectric Barrier ◽  
Piv Measurement

The structures of a flow field induced by a plasma actuator were investigated experimentally in quiescent air using high-speed Particle Image Velocimetry (PIV) technology. The motivation behind was to figure out the flow control mechanism of the plasma technique. A symmetrical Dielectric Barrier Discharge (DBD) plasma actuator was mounted on the suction side of the SC (2)-0714 supercritical airfoil. The results demonstrated that the plasma jet had some coherent structures in the separated shear layer and these structures were linked to a dominant frequency of [Formula: see text] = 39 Hz when the peak-to-peak voltage of plasma actuator was 9.8 kV. The high speed PIV measurement of the induced airflow suggested that the plasma actuator could excite the flow instabilities which lead to production of the roll-up vortex. Analysis of transient results indicated that the roll-up vortices had the process of formation, movement, merging and breakdown. This could promote the entrainment effect of plasma actuator between the outside airflow and boundary layer flow, which is very important for flow control applications.

Flow Control on a Transport Truck Side Mirror Using Plasma Actuators

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Theodoros Michelis ◽  
Marios Kotsonis
Keyword(s):  
Flow Control ◽  
Guide Vane ◽  
Leading Edge ◽  
Plasma Actuator ◽  
Plasma Actuators ◽  
Dbd Plasma ◽  
Reference Case ◽  
Image Velocimetry ◽  
Wind Tunnel Study ◽  
Edge Separation

A wind tunnel study is conducted toward hybrid flow control of a full scale transport truck side mirror at ReD=3.2×105. A slim guide vane is employed for redirecting high-momentum flow toward the mirror wake region. Leading edge separation from the guide vane is reduced or eliminated by means of an alternating current -dielectric barrier discharge (AC-DBD) plasma actuator. Particle image velocimetry (PIV) measurements are performed at a range of velocities from 15 to 25 m/s and from windward to leeward angles from -5deg to 5deg. Time-averaged velocity fields are obtained at the center of the mirror for three scenarios: (a) reference case lacking any control elements, (b) guide vane only, and (c) combination of the guide vane and the AC-DBD plasma actuator. The comparison of cases demonstrates that at 25 m/s windward conditions (-5deg) the guide vane is capable of recovering 17% momentum with respect to the reference case. No significant change is observed by activating the AC-DBD plasma actuator. In contrast, at leeward conditions (5deg), the guide vane results in a −20% momentum loss that is rectified to a 6% recovery with actuation. The above implies that for a truck with two mirrors, 23% of momentum may be recovered.

Optimization and Evaluation of Multiple DBD Plasma Actuators Applied in the Tip Leakage Control for Turbine Cascade

2019 ◽  
Author(s):  
Jianyang Yu ◽  
Wenchun Bao ◽  
Fu Chen ◽  
Yanping Song ◽  
Cong Wang
Keyword(s):  
Flow Control ◽  
Mass Flow ◽  
Suction Side ◽  
Plasma Actuator ◽  
Plasma Actuators ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Dbd Plasma ◽  
Tip Leakage ◽  
Leakage Control

Abstract The dielectric barrier discharge (DBD) plasma actuator, in which electrodes are asymmetric arranged, has already demonstrated its ability in flow control. In the present work, the configuration of multiple plasma actuators is placed at the suction side of the cascade top to realize the tip leakage control. However, massive configurations appear when the number of plasma actuators increases, resulting in the investigation of actuator configuration for tip leakage flow control becomes a challenge. The surrogate modelling approach provides a cheap and efficient method to investigate the effect of multiple plasma actuators on the tip leakage flow control. By constructing an approximation model, tip leakage mass flow rates of all configuration are obtained in the present work. What’s more, the flow structures in the tip clearance controlled by the plasma actuators are explained in the process of topological analysis. The results show that the tip leakage mass flow rate is decreasing with the number of active plasma actuators increasing. However, the decreasing would reach its limits in the process of adding plasma actuators. In the analysis of flow topology, single actuator would generate a small vortex at the suction side to cause an obstacle in the tip leakage flow. While the continuous arrangements of plasma actuator is beneficial to generate an induced vortex to diminish the tip leakage flow.

scholarly journals Flow control over an airfoil using virtual Gurney flaps

2015 ◽  
Vol 767 ◽  
pp. 595-626 ◽  
Author(s):  
Li-Hao Feng ◽  
Kwing-So Choi ◽  
Jin-Jun Wang
Keyword(s):  
Flow Control ◽  
Shear Layer ◽  
Plasma Actuator ◽  
Recirculation Region ◽  
Dbd Plasma ◽  
Near Wake ◽  
Trailing Edge ◽  
Pressure Surface ◽  
Gurney Flaps ◽  
Gurney Flap

AbstractFlow control over a NACA 0012 airfoil is carried out using a dielectric barrier discharge (DBD) plasma actuator at the Reynolds number of 20 000. Here, the plasma actuator is placed over the pressure (lower) side of the airfoil near the trailing edge, which produces a wall jet against the free stream. This reverse flow creates a quasi-steady recirculation region, reducing the velocity over the pressure side of the airfoil. On the other hand, the air over the suction (upper) side of the airfoil is drawn by the recirculation, increasing its velocity. Measured phase-averaged vorticity and velocity fields also indicate that the recirculation region created by the plasma actuator over the pressure surface modifies the near-wake dynamics. These flow modifications around the airfoil lead to an increase in the lift coefficient, which is similar to the effect of a mechanical Gurney flap. This configuration of DBD plasma actuators, which is investigated for the first time in this study, is therefore called a virtual Gurney flap. The purpose of this investigation is to understand the mechanism of lift enhancement by virtual Gurney flaps by carefully studying the global flow behaviour over the airfoil. First, the recirculation region draws the air from the suction surface around the trailing edge. The upper shear layer then interacts with the opposite-signed shear layer from the pressure surface, creating a stronger vortex shedding from the airfoil. Secondly, the recirculation region created by a DBD plasma actuator over the pressure surface displaces the positive shear layer away from the airfoil, thereby shifting the near-wake region downwards. The virtual Gurney flap also changes the dynamics of laminar separation bubbles and associated vortical structures by accelerating laminar-to-turbulent transition through the Kelvin–Helmholtz instability mechanism. In particular, the separation point and the start of transition are advanced. The reattachment point also moves upstream with plasma control, although it is slightly delayed at a large angle of attack.

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