Unseeded and Seeded PIV Measurements of River Flows Videotaped from a Helicopter

Article type: Research Article

Authors: Fujita, I. | Hino, T.

Affiliations: Research Center for Urban Safety and Security, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan. Tel: +81-78-803-6439; FAX: +81-78-803-6394; E-mail: ifujita@kobe-u.ac.jp | Kinki Regional Bureau of the Ministry of Land, Infrastructure and Transport, Osaka, Japan

Abstract: A new PIV method for measuring river surface flows using videotaped images taken from a helicopter has heen developed. In this method, shifting of background images while videotaping was effectively corrected using the known coordinates of fixed points on the image. In low flow conditions, river surface flows were visualized using rice crackers, while in flood flow conditions surface ripples generated by the effects of near-surface turbulence and pressure fluctuation were used as natural unseeded tracers. The performance of the presented method was verified through its applications to the actual river flow measurements.

Keywords: Unseeded visualization, Seeding, PIV, River flow, Flood, Helicopter

Journal: Journal of Visualization, vol. 6, no. 3, pp. 245-252, 2003