5.3.2 Optical measurements

Authors: Wren, Daniel

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 3/5/2014
Publication Date: 1/8/2018
Citation: Wren, D.G. 2018. 5.3.2 Optical measurements. In: Experimental Hydraulics: Flows, Methods, Instrumentation, Data Analysis & Management, Vol II Instrumentation and Measurement Techniques, M. Muste, J. Aberle, D. Admiraal, R. Ettema, M.H. Garcia, D. Lyn, V. Nikora, and C. Rennie (Eds.). CRC Press/Balkema. PP 280-283.

Interpretive Summary: Laboratory and field experiments are critical for understanding and advancing many different aspects of hydraulics and related disciplines. Often studies are carried out in laboratories under less than ideal conditions that may significantly influence experimental outcomes and with instruments not always well suited for the measurement environment . These limitations need to be understood and addressed with appropriate methods. The evolution of new instrumentation has not been supported by accessible and well-documented literature on their use. Additionally, advances in acoustic and optical instrumentation make complex field experiments increasingly feasible. While field instrumentation and experimentation have many similarities to those used in laboratory, the literature on field experimentation is relatively scarce and scattered. Practical information on many aspects of experimental hydraulics presently can only be found in scientific papers or a few dated monographs on laboratory practice. This chapter provides guidance for a practitioner who needs to use optical methods to measure suspended sediment in flowing water. Optical scattering and laser-based methods are covered.

Technical Abstract: A comprehensive guide to experimental hydraulics is long overdue. The proposed book first highlights the intrinsic connection between theory and experiment,emphasizing the need for their complementary use. Described next are considerations for the effective design of experiments, including the selection of facilities and instruments needed for less common experiments. The book devotes considerable space to introducing instrumentation for various types of hydraulics experiments. Conventional instruments are briefly introduced in terms of their capabilities and limitations as guidance on the best sources of information describing them in full will be provided. The more recent instrumentation will receive greater attention through descriptions of operating principles, capabilities and limitations and case studies. Subsequently covered are essential aspects of data processing, uncertainty assessment, and, reporting, and management of experimental data using hydroinformatics tool.