Experimental Investigation of Transitional Natural Convection in a Cube Using Particle Image Velocimetry—Part I: Fluid Flow and Thermal Fields

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Marios D. Georgiou ◽  
Aristides M. Bonanos ◽  
John G. Georgiadis
Keyword(s):  
Experimental Investigation ◽  
Particle Image Velocimetry ◽  
Natural Convection ◽  
Particle Image ◽  
Middle Plane ◽  
Number Range ◽  
Thermal Fields ◽  
Image Velocimetry ◽  
Cold Walls ◽  
Estimated Error

An experimental investigation of transitional natural convection in an air filled cube was conducted in this research. The characteristic dimension of the enclosure is 0.35 m, and data were collected in the middle plane of the cavity. The Rayleigh number range examined is 5.0×107≤Ra≤3.4×108. This was achieved by varying the temperature on the hot and cold walls. The velocity field in the middle plane is measured using particle image velocimetry (PIV). Temperature measurements in the core of the enclosure indicate a linear profile. The average Nu number is also presented and compared against other correlations in the literature. This study attempts to close the gap of available experimental data in literature and provide experimental benchmark data that can be used to validate computational fluid dynamics (CFD) codes since the estimated error from PIV measurements is within 1–2%.

Experimental Investigation of Transitional Natural Convection in a Cube Using Particle Image Velocimetry—Part II: Turbulence Quantities and Proper Orthogonal Decomposition

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Marios D. Georgiou ◽  
Aristides M. Bonanos ◽  
John G. Georgiadis
Keyword(s):  
Experimental Data ◽  
Experimental Investigation ◽  
Particle Image Velocimetry ◽  
Natural Convection ◽  
Proper Orthogonal Decomposition ◽  
Particle Image ◽  
Orthogonal Decomposition ◽  
Number Range ◽  
Image Velocimetry ◽  
Proper Orthogonal

An experimental investigation of transitional natural convection in an air filled cube was conducted in this research. The characteristic dimension of the enclosure was H = 0.35 m, and data were collected in the middle plane of the cavity. The Rayleigh number range examined was 5.0×107≤Ra≤3.4×108. In Part I, the authors presented the mean velocity profiles in the enclosure and conducted heat transfer measurements on the hot wall. An expression between Nu and Ra numbers was concluded and compared against other correlations available in literature. In the present work, the authors present a complete description of the flow in the enclosure by quantifying the low turbulence regime developed in the cavity. This was accomplished by estimating Reynolds stresses, turbulent kinetic energy, vorticity, and swirling strength. Proper orthogonal decomposition (POD) was employed to analyze the flow fields obtained from the experimental data and retain the most salient features of the flow field. This study attempts to close the gap of available experimental data in the literature and provide experimental benchmark data that can be used to validate CFD codes since the estimated error from particle image velocimetry (PIV) measurements is within 1–2%.

scholarly journals Experimental Validation of Falling Liquid Film Models: Velocity Assumption and Velocity Field Comparison

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1205
Author(s):  
Ruiqi Wang ◽  
Riqiang Duan ◽  
Haijun Jia
Keyword(s):  
Experimental Data ◽  
Particle Image Velocimetry ◽  
Velocity Field ◽  
Experimental Validation ◽  
Particle Image ◽  
Velocity Fields ◽  
Number Range ◽  
Comparison Results ◽  
Image Velocimetry ◽  
Experimental Particle

This publication focuses on the experimental validation of film models by comparing constructed and experimental velocity fields based on model and elementary experimental data. The film experiment covers Kapitza numbers Ka = 278.8 and Ka = 4538.6, a Reynolds number range of 1.6–52, and disturbance frequencies of 0, 2, 5, and 7 Hz. Compared to previous publications, the applied methodology has boundary identification procedures that are more refined and provide additional adaptive particle image velocimetry (PIV) method access to synthetic particle images. The experimental method was validated with a comparison with experimental particle image velocimetry and planar laser induced fluorescence (PIV/PLIF) results, Nusselt’s theoretical prediction, and experimental particle tracking velocimetry (PTV) results of flat steady cases, and a good continuity equation reproduction of transient cases proves the method’s fidelity. The velocity fields are reconstructed based on different film flow model velocity profile assumptions such as experimental film thickness, flow rates, and their derivatives, providing a validation method of film model by comparison between reconstructed velocity experimental data and experimental velocity data. The comparison results show that the first-order weighted residual model (WRM) and regularized model (RM) are very similar, although they may fail to predict the velocity field in rapidly changing zones such as the front of the main hump and the first capillary wave troughs.

Experimental investigation of a twice-shocked spherical gas inhomogeneity with particle image velocimetry

Shock Waves ◽  
2011 ◽  
Vol 21 (3) ◽  
pp. 225-231 ◽  
Author(s):  
N. Haehn ◽  
C. Weber ◽  
J. Oakley ◽  
M. Anderson ◽  
D. Ranjan ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Particle Image Velocimetry ◽  
Particle Image ◽  
Image Velocimetry

Analysis of Particle Image Velocimetry Measurements of Natural Convection in an Enclosure Using Proper Orthogonal Decomposition

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Nirmalendu Biswas ◽  
Souvick Chatterjee ◽  
Mithun Das ◽  
Amlan Garai ◽  
Prokash C. Roy ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Natural Convection ◽  
Velocity Field ◽  
Proper Orthogonal Decomposition ◽  
Particle Image ◽  
Field Measurements ◽  
Orthogonal Decomposition ◽  
Image Velocimetry ◽  
Low Dimensional ◽  
Proper Orthogonal

This work investigates natural convection in an enclosure with localized heating on the bottom wall with a flushed or protruded heat source and cooled on the top and the side walls. Velocity field measurements are done by using 2D particle image velocimetry (PIV) technique. Proper orthogonal decomposition (POD) has been used to create low dimensional approximations of the system for predicting the flow structures. The POD-based analysis reveals the modal structure of the flow field and also allows reconstruction of velocity field at conditions other than those used in PIV study.

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