TY - JOUR
T1 - Velocity profile of thin film flows measured using a confocal microscopy particle image velocimetry system with simultaneous multi depth position
AU - Kikuchi, K.
AU - Mochizuki, O.
N1 - Publisher Copyright:
© 2015 IOP Publishing Ltd.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2015/2/1
Y1 - 2015/2/1
N2 - In this paper, we report a technique for simultaneously visualizing flows near walls at nano-depth positions. To achieve such a high interval of depth gradient, we developed a tilted observation technique in a particle image velocimetry (PIV) system based on confocal microscopy. The focal plane along the bottom of the flow channel was tilted by tilting the micro-channel, enabling depth scanning in the microscopic field of view. Our system is suitable for measuring 3D two-component flow fields. The depth interval was approximately 220 nm over a depth range of 10 μm, depending on the tilt angle of the micro-channel. Applying the proposed system, we visualized the near-wall flow in a drainage film flow under laminar conditions to the depth of approximately 30 μm via vertical scanning from the bottom to the free surface. The velocity gradient was proportional to the distance from the wall, consistent with theoretical predictions. From the measured near-wall velocity gradient, we calculated the wall shear stress. The measurement accuracy was approximately 1.3 times higher in our proposed method than in the conventional confocal micro-PIV method.
AB - In this paper, we report a technique for simultaneously visualizing flows near walls at nano-depth positions. To achieve such a high interval of depth gradient, we developed a tilted observation technique in a particle image velocimetry (PIV) system based on confocal microscopy. The focal plane along the bottom of the flow channel was tilted by tilting the micro-channel, enabling depth scanning in the microscopic field of view. Our system is suitable for measuring 3D two-component flow fields. The depth interval was approximately 220 nm over a depth range of 10 μm, depending on the tilt angle of the micro-channel. Applying the proposed system, we visualized the near-wall flow in a drainage film flow under laminar conditions to the depth of approximately 30 μm via vertical scanning from the bottom to the free surface. The velocity gradient was proportional to the distance from the wall, consistent with theoretical predictions. From the measured near-wall velocity gradient, we calculated the wall shear stress. The measurement accuracy was approximately 1.3 times higher in our proposed method than in the conventional confocal micro-PIV method.
KW - confocal micro-PIV
KW - near wall flow
KW - tilted microscopic observation
KW - wall shear stress
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U2 - 10.1088/0957-0233/26/2/025301
DO - 10.1088/0957-0233/26/2/025301
M3 - Article
AN - SCOPUS:84921391684
VL - 26
JO - Measurement Science and Technology
JF - Measurement Science and Technology
SN - 0957-0233
IS - 2
M1 - 025301
ER -