Time-resolved velocity field measurements of separated flow in front of a vertical fence

2001 ◽  
Vol 31 (3) ◽  
pp. 249-257 ◽  
Author(s):  
H. B. Kim ◽  
S. J. Lee
Keyword(s):  
Velocity Field ◽  
Separated Flow ◽  
Field Measurements ◽  
Time Resolved

Simultaneous three-dimensional temperature and velocity field measurements using astigmatic imaging of non-encapsulated thermo-liquid crystal (TLC) particles

Lab on a Chip ◽  
2015 ◽  
Vol 15 (3) ◽  
pp. 660-663 ◽  
Author(s):  
Rodrigo Segura ◽  
Massimiliano Rossi ◽  
Christian Cierpka ◽  
Christian J. Kähler
Keyword(s):  
Liquid Crystal ◽  
Velocity Field ◽  
Three Dimensional ◽  
Field Measurements ◽  
Velocity Measurements ◽  
Time Resolved

TLC thermography and APTV for simultaneous time-resolved 3D temperature and velocity measurements in microflows.

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.

Evaluating the Influence of Rotor-Casing Eccentricity on Turbine Efficiency Including Time-Resolved Flow Field Measurements

2021 ◽  
pp. 1-33
Author(s):  
Eric DeShong ◽  
Shawn Siroka ◽  
Reid A. Berdanier ◽  
Karen A. Thole
Keyword(s):  
Flow Field ◽  
Magnetic Levitation ◽  
Field Measurements ◽  
Tip Clearance ◽  
Time Resolved ◽  
Flow Angle ◽  
Turbine Efficiency ◽  
Eccentric Rotor ◽  
Blade Tip ◽  
Manufacturing Techniques

Abstract The clearance that exists between the casing and turbine blade tips is one of the key drivers of efficiency in gas turbine engines. For this reason, engine manufacturers utilize precise manufacturing techniques and may employ clearance control systems to minimize tip clearances to reduce associated losses. Despite these efforts, turbines typically exhibit some nominal casing ovality or rotor-casing eccentricity, and changes to blade tip clearance during operation commonly occur due to thermal and mechanical stresses. The present study investigates non-axisymmetric tip clearance effects by creating a rotor-casing eccentricity in a one-stage axial test turbine operating in a continuous-duration mode at engine relevant conditions with engine representative hardware. A magnetic levitation bearing system was leveraged to move the turbine shaft to vary the rotor-casing eccentricity without test section disassembly. The results of this study indicate that rotor-casing eccentricity does not affect overall turbine efficiency over the range that was tested, but does locally influence efficiency and the rotor exit flow field. Comparisons of flow angle and secondary flow kinetic energy agreed with previous studies and existing analytical methods, respectively. Collectively, these results indicate that tip clearance can be studied locally on an eccentric rotor.

scholarly journals Implementation of a Faraday rotation diagnostic at the OMEGA laser facility

2018 ◽  
Vol 6 ◽  
Author(s):  
A. Rigby ◽  
J. Katz ◽  
A. F. A. Bott ◽  
T. G. White ◽  
P. Tzeferacos ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Faraday Rotation ◽  
Field Measurements ◽  
Thomson Scattering ◽  
Proton Radiography ◽  
Time Resolved ◽  
Rotation Measurement ◽  
Laser Facility ◽  
Omega Laser

Magnetic field measurements in turbulent plasmas are often difficult to perform. Here we show that for ${\geqslant}$kG magnetic fields, a time-resolved Faraday rotation measurement can be made at the OMEGA laser facility. This diagnostic has been implemented using the Thomson scattering probe beam and the resultant path-integrated magnetic field has been compared with that of proton radiography. Accurate measurement of magnetic fields is essential for satisfying the scientific goals of many current laser–plasma experiments.

Time resolved flow-field measurements of a turbulent mixing layer over a rectangular cavity

2010 ◽  
Vol 51 (1) ◽  
pp. 51-63 ◽  
Author(s):  
Shiyao Bian ◽  
James F. Driscoll ◽  
Brian R. Elbing ◽  
Steven L. Ceccio
Keyword(s):  
Flow Field ◽  
Turbulent Mixing ◽  
Mixing Layer ◽  
Field Measurements ◽  
Rectangular Cavity ◽  
Time Resolved ◽  
Turbulent Mixing Layer
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