IAHR, founded in 1935, is a worldwide independent member-based organisation of engineers and water specialists working in fields related to the hydro-environmental sciences and their practical application. Activities range from river and maritime hydraulics to water resources development and eco-hydraulics, through to ice engineering, hydroinformatics, and hydraulic machinery.
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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Special sessions : Error analysis for velocity measurements in rotating flow using large scale particle image velocimet...
Error analysis for velocity measurements in rotating flow using large scale particle image velocimetry
Author : SEOJUN KIM (1), KWONKYU YU (2), BYUNGMAN YOON (3) & MYEONGHUI AHN (4)
ABSTRACT
Recent advances in IT technology have enabled us to take advantage of modern instrumentations for stream flow
monitoring. Among others, Large Scale Particle Image Velocimetry (LSPIV) that utilizes remotely recorded video
imaginary has been considered as convenient and cost-effective tools compared with conventional surveying techniques
such as mechanical velocimeter and float. Though the LSPIV technique has been highlighted for hydrologic communities
in the last decades, the applicability in terms of its field operations has brought in several uncertain aspects. In particular, it
is very crucial how to decide the size of interrogation area and time interval between images, since the LSPIV makes use
of visible migration of surface particles to estimate flow velocity. Especially for the rotating flow, the rotating surface pattern
driven by the rotating flow significantly changes particle density distribution when very large size or time interval were
applied. Thus, the determination of an appropriate size of interrogation area and time interval should be more carefully
considered than dealing with straight flow patterns. Before optimally deciding the size of interrogation area and time
interval for the rotating flow, this study aims to provide error analysis accordingly with different rotation angle between two
consecutive images driven by rotating flow and size of interrogation area. The results showed that, for the less than 6
degree of the rotation angle, the error noticeably decreased when the size of interrogation area became increased.
Between 6 to 8 degrees of the rotation angle, however, the error adversely increased for the given size of interrogation
area while the error decreased for the smaller size of interrogation area. Over 8 degree of the rotation angle, the error
remarkably increased. These results indicated that the rotation angle of rotating flow significantly affects the accuracy of
the LSPIV technique.
File Size : 634,119 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Special sessions
Date Published : 19/08/2015
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