Dynamic Roughness as a Means of Leading-Edge Separation Flow Control

2012 ◽  
Vol 49 (1) ◽  
pp. 108-115 ◽  
Author(s):  
W. W. Huebsch ◽  
P. D. Gall ◽  
S. D. Hamburg ◽  
A. P. Rothmayer
Keyword(s):  
Flow Control ◽  
Leading Edge ◽  
Separation Flow ◽  
Dynamic Roughness ◽  
Edge Separation

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.

scholarly journals Separated Flow Control of Small Horizontal-Axis Wind Turbine Blades Using Dielectric Barrier Discharge Plasma Actuators

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1218 ◽  
Author(s):  
Hikaru Aono ◽  
Hiroaki Fukumoto ◽  
Yoshiaki Abe ◽  
Makoto Sato ◽  
Taku Nonomura ◽  
...  
Keyword(s):  
Flow Control ◽  
Discharge Plasma ◽  
Barrier Discharge ◽  
Leading Edge ◽  
Dielectric Barrier Discharge Plasma ◽  
Horizontal Axis Wind Turbine ◽  
Dielectric Barrier ◽  
Torque Generation ◽  
Barrier Discharge Plasma ◽  
Edge Separation

The flow control over the blades of a small horizontal-axis wind turbine (HAWT) model using a dielectric barrier discharge plasma actuator (DBD-PA) was studied based on large-eddy simulations. The numerical simulations were performed with a high-resolution computational method, and the effects of the DBD-PA on the flow fields around the blades were modeled as a spatial body force distribution. The DBD-PA was installed at the leading edge of the blades, and its impacts on the flow fields and axial torque generation were discussed. The increase in the ratios of the computed, cycle-averaged axial torque reasonably agreed with that of the available experimental data. In addition, the computed results presented a maximum of 19% increase in the cycle-averaged axial torque generation by modulating the operating parameters of the DBD-PA because of the suppression of the leading edge separation when the blade’s effective angles of attack were relatively high. Thus, the suppression of the leading edge separation by flow control can lead to a delay in the breakdown of the tip vortex as a secondary effect.

908 Leading Edge Separation Flow from Airfoil for Wind Turbine

2001 ◽  
Vol 2001 (0) ◽  
pp. 235-236
Author(s):  
Masatoshi Yano ◽  
Eizi Kato ◽  
Tutom Tachikawa
Keyword(s):  
Wind Turbine ◽  
Leading Edge ◽  
Separation Flow ◽  
Edge Separation

A theoretical investigation of enhanced lift in the presence of thin aerofoil stall

1999 ◽  
Vol 103 (1023) ◽  
pp. 237-244 ◽  
Author(s):  
W. W. H. Yeung ◽  
G. V. Parkinson
Keyword(s):  
Flat Plate ◽  
Flow Model ◽  
Separated Flow ◽  
Leading Edge ◽  
Geometrical Parameters ◽  
Separation Flow ◽  
Attached Flow ◽  
Positive Angle ◽  
Edge Separation ◽  
Potential Flow Model

Abstract A theoretical study is presented for the investigation of a potential-flow model for enhancing lift over a flat-plate aerofoil experiencing thin aerofoil stall. Rather than suppressing the leading-edge separation, flow is assumed to separate tangentially at the leading edge and made to reattach smoothly at the tip of a forward-facing fence joining the plate tangentially on its upper surface to avoid any unnecessary stagnated flow. The length of the fence and its location from the leading edge form two geometrical parameters. At any positive angle of attack, the resulting bounding streamline emanating from the leading edge and terminating at the tip of the fence is simulated by using suitable mathematical singularities subject to boundary conditions such as attaining a finite velocity at each critical point of the conformal mapping involved, and the condition of finite pressure gradient at reattachment, when applicable. Computational results from varying these two geometrical parameters indicate that the lift from each model is enhanced, as compared with the attached flow model around a simple flat plate and the original separated flow model by Kirchhoff.

scholarly journals Flow control of leading edge separation using DBD plasma actuator

2014 ◽  
Vol 80 (813) ◽  
pp. FE0118-FE0118 ◽  
Author(s):  
Yasuaki KOZATO ◽  
Yuta HIROSE ◽  
Satoshi KIKUCHI ◽  
Shigeki IMAO
Keyword(s):  
Flow Control ◽  
Leading Edge ◽  
Plasma Actuator ◽  
Dbd Plasma ◽  
Edge Separation

Rotational temperature imaging of a leading-edge separation in hypervelocity flow

2019 ◽  
Author(s):  
Laurent M. Le Page ◽  
Matthew Barrett ◽  
Sean O’Byrne ◽  
Sudhir L. Gai
Keyword(s):  
Rotational Temperature ◽  
Leading Edge ◽  
Temperature Imaging ◽  
Edge Separation

Three-Dimensional and Rotational Aerodynamics on the NREL Phase VI Wind Turbine Blade

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Alvaro Gonzalez ◽  
Xabier Munduate
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Three Dimensional ◽  
Separated Flow ◽  
Leading Edge ◽  
Wind Turbine Blade ◽  
Trailing Edge ◽  
Rotating Blade ◽  
Nrel Phase Vi ◽  
Edge Separation

This work undertakes an aerodynamic analysis over the parked and the rotating NREL Phase VI wind turbine blade. The experimental sequences from NASA Ames wind tunnel selected for this study respond to the parked blade and the rotating configuration, both for the upwind, two-bladed wind turbine operating at nonyawed conditions. The objective is to bring some light into the nature of the flow field and especially the type of stall behavior observed when 2D aerofoil steady measurements are compared to the parked blade and the latter to the rotating one. From averaged pressure coefficients together with their standard deviation values, trailing and leading edge separated flow regions have been found, with the limitations of the repeatability of the flow encountered on the blade. Results for the parked blade show the progressive delay from tip to root of the trailing edge separation process, with respect to the 2D profile, and also reveal a local region of leading edge separated flow or bubble at the inner, 30% and 47% of the blade. For the rotating blade, results at inboard 30% and 47% stations show a dramatic suppression of the trailing edge separation, and the development of a leading edge separation structure connected with the extra lift.

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