Numerical and experimental analysis of turbulent boundary layer control with piezo-ceramic actuator

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1217-1226
Author(s):  
Dawei Li ◽  
Guijuan Li ◽  
Lin Sun ◽  
Yunfei Chen
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Turbulent Boundary Layer ◽  
Leading Edge ◽  
Active Surface ◽  
Control Parameters ◽  
Wind Tunnel Experiments ◽  
Turbulence Length ◽  
Turbulence Length Scale ◽  
Layer Control

The effects of smart-material-based active surface perturbation (i.e. piezo-ceramic actuators) on wall shear stress and noise metric have been investigated by simulations and wind tunnel experiments. A periodic vibration through the application of piezo-ceramic actuators is imposed on the surface of a plate, and the vibration position is located on the upper part of the leading edge of the plate. Both the control results from simulations and experiments are close to each other, when the control parameters are the same. The simulations and wind tunnel experiments show that downstream skin-friction drag and noise metric can be reduced with the active control, and the reductions strongly depend on control parameters. Comparing with the near wall flow structures, the turbulent kinetic energy and characteristic turbulence length scale in the turbulent boundary layer can be controlled with the piezo-ceramic actuator.

scholarly journals STUDI EKSPERIMEN OIL FLOW VISUALIZATION PADA AIRFOIL NACA 0012 DENGAN TRAPEZOIDAL VORTEX GENERATOR MENGGUNAKAN OPEN CIRCUIT SUBSONIC WIND TUNNEL

2019 ◽  
Vol 4 (4) ◽  
pp. 1-9
Author(s):  
Setyo Hariyadi ◽  
Habibie Aldo putra
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Turbulent Boundary Layer ◽  
Vortex Generator ◽  
Leading Edge ◽  
Open Circuit ◽  
Subsonic Wind Tunnel ◽  
Oil Flow ◽  
Oil Flow Visualization ◽  
Naca 0012

Pada pembuatan suatu pesawat terbang, suatu analisis sebelum terbang terhadap kinerja aerodinamika dari pesawat tersebut sangat diperlukan, terutama untuk daerah dimana metoda analitik/empirik tidak dapat menjangkaunya seperti perkiraan CLmax, karakteristik stall dan lain-lainnya. Satu hal penting yang harus diperhatikan dalam pendesainan suatu pesawat yaitu pemilihan airfoil dan modifikasinya. Modifikasi airfoil dilakukan untuk menunda separasi aliran dan meningkatkan performa airfoil, salah satunya dengan vortex generator. Hal ini dapat diindikasikan dengan tertundanya separasi aliran yang melintasi permukaan atas dari airfoil. Topik yang dikaji dalam penelitian ini adalah aliran melintasi airfoil NACA 0012 dengan penambahan vortex generator. Tujuan penelitian ini adalah untuk membandingkan karakteristik aliran fluida dengan dan tanpa penambahan vortex generator. Profil vortex generator yang digunakan adalah trapezoidal vortex generator dengan konfigurasi straight dan ditempatkan pada x/c = 20% arah chord line dari leading edge. Variasi yang digunakan adalah bilangan Reynolds (Re) dan sudut serang (α) pada airfoil. Kecepatan freestream yang digunakan yaitu kecepatan 10 m/s dan 20 m/s, pada sudut serang (α) 0°, 4°, 10°, 12°, 15°,dan 17°. Dari penelitian ini didapatkan performa aerodinamika dan fenomena aliran di sekitar airfoil. Perihal ini ada peningkatan performa aerodinamika pesawat dari sudut serang 0° sampai sudut serang 12° terbukti dengan meningkatnya kecepatan transisi dari laminar boundary layer menjadi turbulent boundary layer.

Effect of a Triangular Rib on a Flat Plate Boundary Layer

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
F. Fouladi ◽  
P. Henshaw ◽  
D. S.-K. Ting
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Flat Plate ◽  
Turbulence Intensity ◽  
Plate Boundary ◽  
Leading Edge ◽  
Smooth Wall ◽  
Turbulence Length ◽  
Turbulence Parameters ◽  
Flat Plate Boundary Layer

The flow structure downstream of a triangular rib over a thin plate placed in a wind tunnel was experimentally investigated using a boundary layer hotwire anemometer. Flow and boundary layer characteristics, such as thickness, shape, and turbulence parameters, were studied at different freestream velocities and streamwise locations corresponding to ReX of 1.7 × 104–2.8 × 105 for plates without and with a leading edge rib. It was found that the boundary layer of the flow over a ribbed wall was 3–3.5 times thicker and had higher turbulence intensity and smaller turbulence length scales compared to its smooth wall counterpart.

Turbulent boundary layer control utilizing the Lorentz force

2000 ◽  
Vol 12 (3) ◽  
pp. 631-649 ◽  
Author(s):  
Timothy W. Berger ◽  
John Kim ◽  
Changhoon Lee ◽  
Junwoo Lim
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Lorentz Force ◽  
Boundary Layer Control ◽  
Layer Control

Mechanically Amplified Piezoelectric Microactuators for Laminar-Turbulent Transition Control on Airfoils

2009 ◽  
Vol 6 (4) ◽  
pp. 211-218 ◽  
Author(s):  
C. Bolzmacher ◽  
X. Riedl ◽  
J. Leuckert ◽  
M. Engert ◽  
K. Bauer ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
High Speed ◽  
Leading Edge ◽  
Transition Process ◽  
Open Loop ◽  
Film Sensor ◽  
Transition Control ◽  
Transitional Boundary Layer ◽  
Tollmien Schlichting

Drag reduction on airfoils using arrays of micro-actuators is one application of so-called Aero-MEMS. These microactuators interact with TS instabilities (Tollmien-Schlichting waves) inside a transitional boundary layer by superimposing artificially generated counterwaves in order to delay the transition process. These actuators need to exhibit a relatively large stroke at relatively high operational frequencies when operated at high Mach numbers. For this purpose, a novel micromachined mechanical amplification unit for increasing the stroke of piezoelectric microactuators up to high frequencies is proposed. The mechanical lever is provided by a sliced nickel titanium membrane. In this work, the actuator is explained in detail and wind tunnel experiments are carried out to investigate the effect of this mechanically amplified piezoelectric microactuator on thin transitional boundary layers. The experiments have been carried out in the transonic wind tunnel facility of the Berlin University of Technology on an unswept test wing with an NACA 0004 leading edge. The effectiveness of the actuator for flow control applications is determined in an open-loop setup consisting of one actuator having a relevant spanwise extension and a microstructured hot film sensor array located downstream. The aerodynamic results at Mach 0.33 are presented and discussed. It is shown that the actuator influences TS wave specific frequencies between 2.5 kHz and 7.4 kHz. The actuator amplitude is large enough to influence a transitional boundary layer significantly without bypassing the natural transition process which makes this type of micromachined actuator a candidate for high speed TS-control.

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