Influence of Main Flow on Vortex Structure Generated by Burst Mode Actuation of DBD Plasma Actuator

2022 ◽  
Author(s):  
Kenta Emori ◽  
Yutaka Kaneko ◽  
Hiroyuki Nishida
Author(s):  
Kengo Asada ◽  
Kozo Fujii

The relation between aerodynamic characteristics and the effectiveness of separation control with the DBD plasma actuator over the airfoil are discussed. The flow-fields around the NACA0015 airfoil are simulated with implicit large-eddy simulation using compact difference scheme. The normal mode generates moderately separated region over the airfoil and gains lift by negative pressure at the vortex center. The burst mode with nondimensional burst frequency of 1 enhances the vortex shedding from the separation shear layer and avoid the massive separation from the leading edge. However, the lift coefficient oscillate very much, in this case. The burst mode with nondimensional burst frequency of 6 improves the airfoil performance by suppressing the separation region. These facts indicate that the unsteady aerodynamic characteristics must be discussed when the effectiveness of separation control is evaluated.


2017 ◽  
Vol 29 (2) ◽  
pp. 024104 ◽  
Author(s):  
Bal Krishan Mishra ◽  
P. K. Panigrahi

Author(s):  
Taku Nonomura ◽  
Satoshi Sekimoto ◽  
Kengo Asada ◽  
Akira Oyama ◽  
Kozo Fujii

An experimental study of plasma actuator on separation control is conducted. The plasma actuator is used for control of separated flow around NACA0015 airfoil. The Reynolds number based on chord length is set to 60,000 and the angle of attack is set to 12[deg]. The plasma actuator is applied with normal mode and burst mode, where normal mode denotes continuous actuation and burst mode denotes temporary intermittent actuation. Also, actuations for co-flow blowing and counter blowing are conducted. The averaged pressure coefficients of wing surface and velocity fields are measured. For velocity fields, PIV measurement is adopted. Comparing counter and co-flow blowings of plasma actuator, the effects of counter blowing is investigated. Also, for both co-flow and counter blowing cases, we investigate the effects of burst mode. Through the series of experiments, following two types of mechanism for separation control will be discussed. One type is considered to be directly giving momentum in the boundary layer which seems to be more active in co-flow blowing with normal mode. The other type is considered to be enhancement of the mixing, leading to increase in momentum thickness of the boundary layer. The latter mechanism seems to be active in the burst mode with both co-flow and counter blowing.


2019 ◽  
Vol 85 (869) ◽  
pp. 18-00368-18-00368 ◽  
Author(s):  
Keunseob LEE ◽  
Satoshi KIKUCHI ◽  
Shigeki IMAO

Author(s):  
Takehiko Segawa ◽  
Hiro Yoshida ◽  
Shinya Takekawa ◽  
Timothy Jukes ◽  
Kwing-So Choi

Properties of coaxial annular jets produced by a dielectric barrier discharge (DBD) plasma actuator with a doughnut shaped electrodes were investigated under atmospheric pressure and room temperature. The actuator consists of two circular electrodes sandwiching a thin dielectric layer. By applying 0 – ±3.3 kV between the electrodes at radio frequencies, the plasma jet is formed near the inner edge of the top electrode. The radial jet runs toward the center of the electrode and then impinges at the center to generate a wall normal annular jet. The evolution of the wall normal jet was observed precisely using particle image velocimetry (PIV) system. It was found that characteristic velocities increase in proportion to the bursting frequency and inversely proportional to the inner diameter of the electrode at the surging time of the voltage at 5.0 × 10−6sec.


Author(s):  
Takeshi Watanabe ◽  
Hikaru Aono ◽  
Tomoaki Tatsukawa ◽  
Taku Nonomura ◽  
Akira Oyama ◽  
...  

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