Effect of Passive Flow Control Devices on Base Pressure for Mach Numbers Between 0.5 and 1.4

2021 ◽  
Author(s):  
Jayaprakash Narayan Murugan ◽  
Kiran Chutkey ◽  
Sri Raghu Royyuru ◽  
Shashi Bhushan Verma
Keyword(s):  
Base Pressure ◽  
Base Case ◽  
Test Cases ◽  
Base Surface ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Flow Control Devices ◽  
Ventilated Cavity ◽  
Control Devices ◽  
Mach Numbers

Abstract Experimental studies are carried out on an axisymmetric cylindrical base body for six freestream Mach numbers between 0.54 to 1.41. Unsteady pressure is measured on the base surface using high-frequency response Kulite pressure transducers. The effect of passive flow control devices on the mean base pressure and the unsteady characteristics of base pressure has been studied. A blunt base, a conventional cavity device and three different ventilated cavity devices have been tested along with four different rounded base lip devices. A total of 20 different base geometric modifications are tested at six freestream Mach numbers resulting in 120 test cases. The cavity devices improve the base pressure as compared to the blunt base case. Among all the cases considered, a maximum increase of 8.6% in the base pressure coefficient is noticed for the Normal Ventilated Cavity device as compared to the blunt base case for freestream Mach number of 1.22. The power spectral density of base pressure fluctuations revealed the dominant peaks on the base surface. The shear layer flapping frequency for all the cases have been found and the Strouhal number based on base diameter varies between 0.2 to 0.27. In the presence of cavity devices, dominant peaks are observed in the range of 2 kHz to 8 kHz which can be attributed to the vigorous action within the recirculation bubble. Maximum reduction in base pressure fluctuation is observed for the Normal & Inclined Ventilated Cavity device configuration test cases.

Experimental Analysis on a Model of a Small Ducted Wind Turbine Equipped with Passive Flow Control Devices

2021 ◽  
Author(s):  
Elena-Alexandra Chiulan ◽  
Costin Ioan Cosoiu ◽  
Andrei-Mugur Georgescu ◽  
Anton Anton ◽  
Mircea Degeratu
Keyword(s):  
Flow Control ◽  
Wind Turbine ◽  
Experimental Analysis ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Flow Control Devices ◽  
Control Devices

scholarly journals Fundamental Studies of Vortices Induced by a Vortex-Generator for Automotive Applications

2014 ◽  
Vol 553 ◽  
pp. 211-216
Author(s):  
Asiful Islam ◽  
Graham Doig
Keyword(s):  
Turbulence Models ◽  
Vortex Generator ◽  
Automotive Applications ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Flow Control Devices ◽  
Simple Geometry ◽  
Image Velocimetry ◽  
Control Devices ◽  
Spatial Trajectory

For automotive applications, passive flow control devices can be used to reduce, delay or prevent flow separation. This study explores the nature of vortex generation and behaviour, numerically and experimentally, for a simple geometry at a Reynolds Number (Rex) of 5×105 and 1.945×106. The setup comprised a triangular vane vortex-generator mounted on a shallow ramp referenced from literature. Flow over the isolated ramp was validated with past experimental particle-image-velocimetry (PIV) data, which also highlighted the relative performance of various turbulence models. A parametric study was undertaken with the vane orientation defined by an angle-of-attack (β) and stream-wise location (xedge/xVG). These results revealed relationships between geometric parameters of the vortex generator, as well as the influence of the boundary layer thickness (hVG/δ), on the spatial trajectory of induced vortices.

Further Investigation of Vertical Stabilizer with Passive Flow Control Devices

2020 ◽  
Author(s):  
Yasushi Ito ◽  
Shunsuke Koike ◽  
Mitsuhiro Murayama ◽  
Yoshiyasu Ichikawa ◽  
Kazuyuki Nakakita ◽  
...  
Keyword(s):  
Flow Control ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Flow Control Devices ◽  
Control Devices

Influence of Passive Flow-Control Devices on the Pressure Fluctuations at Wing-Body Junction Flows

2007 ◽  
Vol 129 (8) ◽  
pp. 1030-1037 ◽  
Author(s):  
Semih M. Ölçmen ◽  
Roger L. Simpson
Keyword(s):  
Flow Control ◽  
High Surface ◽  
Pressure Fluctuations ◽  
Wall Pressure ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Wall Pressure Fluctuations ◽  
Flow Control Devices ◽  
Zero Degree ◽  
Control Devices

The effectiveness of passive flow-control devices in eliminating high surface rms pressure fluctuations at the junction of several idealized wing/body junction flows was studied. Wall-pressure fluctuation measurements were made using microphones along the line of symmetry at the wing/body junction of six different wing shapes. The wings were mounted on the wind tunnel floor at a zero degree angle-of-attack. The six wing shapes tested were: a 3:2 semi-elliptical-nosed NACA 0020 tailed generic body shape (Rood wing), a parallel center-body model, a tear-drop model, a Sandia 1850 model, and NACA 0015 and NACA 0012 airfoil shapes. Eight different fence configurations were tested with the Rood wing. The two double-fence configurations were found to be the most effective in reducing the pressure fluctuations. Two of the single fence types were nearly as effective and were simpler to manufacture and test. For this reason one of these single fence types was selected for testing with all of the other wing models. The best fence flow-control devices were found to reduce rms wall-pressure fluctuations by at least 61% relative to the baseline cases.

scholarly journals Five Megawatt Wind Turbine Power Output Improvements by Passive Flow Control Devices

Energies ◽  
2017 ◽  
Vol 10 (6) ◽  
pp. 742 ◽  
Author(s):  
Unai Fernandez-Gamiz ◽  
Ekaitz Zulueta ◽  
Ana Boyano ◽  
Igor Ansoategui ◽  
Irantzu Uriarte
Keyword(s):  
Flow Control ◽  
Wind Turbine ◽  
Power Output ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Flow Control Devices ◽  
Control Devices

Asymptotic Wake Behavior of Swept, Blunt Trailing-Edge Airfoils

1994 ◽  
Vol 116 (1) ◽  
pp. 171-174
Author(s):  
G. V. Selby ◽  
F. H. Miandoab
Keyword(s):  
Streamwise Velocity ◽  
Vortex Generators ◽  
Wake Flow ◽  
Sweep Angle ◽  
Passive Flow Control ◽  
Blunt Trailing Edge ◽  
Passive Flow ◽  
Asymptotic Values ◽  
Flow Control Devices ◽  
Control Devices

The effect of base sweep and the addition of passive flow-control devices at constant base sweep angle (30 deg) on the asymptotic behavior of turbulent wakes produced by flatplate airfoils was experimentally examined. It was determined that values of the nondimensional streamwise velocity defect and wake thickness parameters for the grooved model with 30 deg swept base at fourteen base thicknesses downstream of the base at mid-span were closer to asymptotic values from empirical plane wake predictions than values for the 0, 30, and 45 deg swept baseline models and the 30 deg swept model with Wishbone vortex generators. The grooves apparently inhibited the three-dimensionality of the resulting wake flow.

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