Investigation of the Near Wake of a Sphere Using Time-Resolved Stereoscopic Particle Image Velocimetry

2020 ◽  
Author(s):  
D. Nguyen ◽  
N. Anand ◽  
Y. Hassan ◽  
R. Muyshondt
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Stereoscopic Particle Image Velocimetry ◽  
Near Wake ◽  
Time Resolved ◽  
Image Velocimetry

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

2021 ◽  
Vol 143 (7) ◽  
Author(s):  
Katharina Stichling ◽  
Maximilian Elfner ◽  
Hans-Jörg Bauer
Keyword(s):  
Particle Image Velocimetry ◽  
Film Cooling ◽  
Particle Image ◽  
Operating Conditions ◽  
Stereoscopic Particle Image Velocimetry ◽  
Test Rig ◽  
Time Resolved ◽  
Hot Gas ◽  
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 (SPIV) 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 (DR). 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 article image velocimetry data for a film cooling flow at high DR and a range of blowing ratios are presented in this study. The investigated film cooling hole constitutes a 10 deg–10 deg–10 deg 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 deg. The time-resolved data indicate transient behavior of the film cooling jet.

Experimental Analysis of the Near Wake from a Ducted Thruster at True and Near Bollard Pull Conditions Using Stereo Particle Image Velocimetry (SPIV)

2005 ◽  
Vol 127 (3) ◽  
pp. 191-196 ◽  
Author(s):  
S. El Lababidy ◽  
N. Bose ◽  
P. Liu ◽  
D. Walker ◽  
F. Di Felice
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Practical Interest ◽  
Stereoscopic Particle Image Velocimetry ◽  
Wake Flow ◽  
Hydrodynamic Characteristics ◽  
Near Wake ◽  
Image Velocimetry ◽  
Wide Range ◽  
Marine Applications

Thrusters working at low advance coefficients are employed in a wide range of offshore and marine applications on Floating, Production, Storage, and Offloading (FPSO) systems; shuttle tankers; tug boats; and mobile offshore units. Therefore, an understanding of the flow around the thrusters is of great practical interest. Despite this interest, there is lack of knowledge in the description of the hydrodynamic characteristics of a ducted thruster’s wake at bollard pull and low advance coefficient values. This work was aimed at providing detailed data about the hydrodynamic characteristics of a Dynamic Positioning (DP) thruster near wake flow at different low advance coefficient values. Wake measurements were made during cavitation tunnel tests carried out on a ducted propeller model at the Italian Ship Model Basin (INSEAN), Rome, Italy. Through these experiments, the DP thruster near wake velocity components at different downstream axial planes, up to 1.5 diameters downstream, were obtained using a Stereoscopic Particle Image Velocimetry (SPIV) system. These experiments were carried out at different advance coefficient (J) values [bollard pull (J=0), J=0.4 and J=0.45].

A Comparison Between Round Turbulent Jets and Particle-Laden Jets in Crossflow by Using Time-Resolved Stereoscopic Particle Image Velocimetry

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
F. J. Diez ◽  
M. M. Torregrosa ◽  
S. Pothos
Keyword(s):  
Particle Image Velocimetry ◽  
High Intensity ◽  
Particle Image ◽  
Three Dimensional ◽  
Continuous Phase ◽  
Stereoscopic Particle Image Velocimetry ◽  
Dispersed Phase ◽  
Time Resolved ◽  
Image Velocimetry ◽  
Phase Images

Time-resolved stereoscopic particle image velocimetry (TR-ST-PIV) measurements were performed to compare the velocity and vorticity field, and the three-dimensional high intensity vorticity structures between a round turbulent single-phase jet and a particle-laden jet in crossflow. The experiments involved steady fresh water jet sources with a particle mass loading of ∼2.0% injected into steady fresh water crossflows. The TR-ST-PIV system was combined with a phase discrimination method that separates two-phase stereo PIV images into dispersed phase images and continuous phase images that are analyzed by using particle tracking velocimetry and stereo-PIV algorithms, respectively. The analysis shows the importance of phase separation for accurate velocity results. It provides instantaneous velocity fields where the dispersed phase preferentially concentrated in regions of low vorticity with the velocity not matching the continuous phase. The jet and the particle-laden jets trajectories are compared to each other and with results in the literature. Similarly, a comparison of mean velocity and vorticity fields between both flows suggest enhanced mixing in the particle-laden jet due to the effects of the dispersed phased which lowered the centerline velocities and enhanced the penetration in the cross-stream direction of the continuous phase. The Taylor’s frozen flow hypothesis is applied to reconstruct the 3D high intensity vorticity structures in a volume. The visualization of the three-dimensional structures corresponding to the intermediate scales of the flow shows slightly elongated structures preferentially aligned with the jet centerline axis.

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