Stereo Particle Image Velocimetry Measurements of Transition Downstream of a Foward-Facing Step in a Swept-Wing Boundary Layer

2017 ◽  
Author(s):  
Jenna L. Eppink
Keyword(s):  
Boundary Layer ◽  
Particle Image Velocimetry ◽  
Particle Image ◽  
Swept Wing ◽  
Image Velocimetry ◽  
Stereo Particle Image Velocimetry

Characteristics of a separated flow past a semicircular leading-edge airfoil model under different imposed pressure gradient

2021 ◽  
pp. 095441002110212
Author(s):  
K Anand ◽  
KT Ganesh
Keyword(s):  
Boundary Layer ◽  
Particle Image Velocimetry ◽  
Pressure Gradient ◽  
Particle Image ◽  
Separation Bubble ◽  
Separated Flow ◽  
Leading Edge ◽  
Field Measurements ◽  
Bench Mark ◽  
Image Velocimetry

The effect of pressure gradient on a separated boundary layer past the leading edge of an airfoil model is studied experimentally using electronically scanned pressure (ESP) and particle image velocimetry (PIV) for a Reynolds number ( Re) of 25,000, based on leading-edge diameter ( D). The features of the boundary layer in the region of separation and its development past the reattachment location are examined for three cases of β (−30°, 0°, and +30°). The bubble parameters such as the onset of separation and transition and the reattachment location are identified from the averaged data obtained from pressure and velocity measurements. Surface pressure measurements obtained from ESP show a surge in wall static pressure for β = −30° (flap deflected up), while it goes down for β = +30° (flap deflected down) compared to the fundamental case, β = 0°. Particle image velocimetry results show that the roll up of the shear layer past the onset of separation is early for β = +30°, owing to higher amplification of background disturbances compared to β = 0° and −30°. Downstream to transition location, the instantaneous field measurements reveal a stretched, disoriented, and at instances bigger vortices for β = +30°, whereas a regular, periodically shed vortices, keeping their identity past the reattachment location, is observed for β = 0° and −30°. Above all, this study presents a new insight on the features of a separation bubble receiving a disturbance from the downstream end of the model, and these results may serve as a bench mark for future studies over an airfoil under similar environment.

Experimental study on the wake fields of a Panamax Bulker based on stereo particle image velocimetry

2018 ◽  
Vol 165 ◽  
pp. 91-106 ◽  
Author(s):  
Chun-yu Guo ◽  
Tie-cheng Wu ◽  
Wan-zhen Luo ◽  
Xin Chang ◽  
Jie Gong ◽  
...  
Keyword(s):  
Experimental Study ◽  
Particle Image Velocimetry ◽  
Particle Image ◽  
Image Velocimetry ◽  
Stereo Particle Image Velocimetry ◽  
Wake Fields

Investigation of Film Cooling Using Time-Resolved Stereo Particle Image Velocimetry

2020 ◽  
Author(s):  
Katharina Stichling ◽  
Maximilian Elfner ◽  
Hans-Jörg Bauer
Keyword(s):  
Particle Image Velocimetry ◽  
Film Cooling ◽  
Particle Image ◽  
Density Ratio ◽  
Test Rig ◽  
Time Resolved ◽  
Hot Gas ◽  
Image Velocimetry ◽  
Stereo Particle Image Velocimetry ◽  
Cooling Air

Abstract In the present study an existing test rig at the Institute of Thermal Turbomachinery (ITS), Karlsruhe Institute of Technology (KIT) designed for generic film cooling studies is adopted to accommodate time resolved stereoscopic particle image velocimetry measurements. Through a similarity analysis the test rig geometry is scaled by a factor of about 20. Operating conditions of hot gas and cooling air inlet and exit can be imposed that are compliant with realistic engine conditions including density ratio. The cooling air is supplied by a parallel-to-hot gas coolant flow-configuration with a coolant Reynolds number of 30,000. Time-resolved and time-averaged stereo particle image velocimetry data for a film cooling flow at high density ratio and a range of blowing ratios is presented in this study. The investigated film cooling hole constitutes a 10°-10°-10° laidback fan-shaped hole with a wide spacing of P/D = 8 to insure the absence of jet interaction. The inclination angle amounts to 35°. The time-resolved data indicates transient behaviour of the film cooling jet.

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