★Research topics

Environmental Hydrodynamics Laboratory

Department of Civil & Earth

Resources Engineering

Kyoto University

■■　Urban flooding

It is very important to clarify car behaviors in flooding. We study the critical incipient condition and the subsequent floating motion experimentally, using small-scale model cars. We also study the underground inundation in urban area and the evacuation problems when it occurs.

(Publications)
1. Toda,K.: Urban Flooding and Measures, Journal of Disaster Research, Vol.2, No.3, pp.143-152, 2007.
2. Toda,K., Ishigaki, T., Baba, Y. and Ozaki, T.: Educational activities for urban flood damage reduction using unique facilities, Floods: From Risk to Opportunity (IAHS Pub.357), pp.135-142, 2013.
3. Takebayashi, H., Toda, K., Nakagawa, H. and Zhang, H.: Field and Interview Surveys of the Flood of 2011, Thailand, Journal of Disaster Research, Vol.8, No.3, pp.386-396, 2013.

■■　Interaction between flow resistance and aquatic plant motion

In actual rivers, many aquatic plants are often observed and they have significance effects on  hydrodynamic properties. The study of its interaction with flow environment is important for the determination of the discharge capacity and ecological condition of the water. We examine the interaction between turbulence structure and coherent waving motion in submerged canopy flows with flexible plant models by a combination of PIV and PTV.

(Publications)
1. Okamoto, T. and Nezu, I.: Spatial evolution of coherent motions in finite-length vegetation patch flow, Environmental Fluid Mechanics, Vol.13 (5), pp.417-434, 2013.
2. Nezu, I. and Okamoto, T: Hydraulics of Vegetated Canopies, Hand book of Environmental Fluid Dynamics, Taylor & Francis Books, Vol.1, pp.285-309, 2012.
3. Okamoto, T. and Nezu, I.: Turbulence structure and “Monami’’ phenomena in flexible vegetated open-channel flows, J. of Hydraulic Res., Vol.47, pp.798-810, 2009.
4. Nezu, I. and Sanjou, M.: Turbulence structure and coherent motion in vegetated open-channel flows, Journal of Hydro-Environment Research, Vol.2, pp.62-90, 2008.

■■　Turbulence Interaction between Air and Water at Free Surface

We study the air-water interfacial turbulence and scalar transfer phenomena across the interface  in wind-induced open-channel flows. The goal of the study is to clarify the air-water turbulent phenomena and to evaluate the turbulent scalar transport with good accuracy by means of experimental approaches and the proposed numerical procedure.

(Publications)
1. Sanjou, M., Nezu, I. and Toda, A.: PIV studies on turbulence structure in air/water interface with wind-induced water waves, Journal of Energy and Power Engineering, David Pub., Vol.5, pp.1063-1067, 2011.
2. Sanjou, M. and Nezu, I.: Turbulent structure and coherent vortices in open-channel flows with wind-induced water waves, Environmental Fluid Mechanics, Vol.11, No.2, pp.113-131.2011.

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■■　Hydrodynamic Characteristics in Open-Channel Flows with Side Cavities

“Wand” has been noticed as one of environmental hydraulic structures in actual rivers. Wand means a side-cavity in rivers, which is made by set groins in rivers bank. In and around Wand, variable aquatic eco-systems are formed. We have been carrying out the turbulent measurements and analyzing flow properties in such Wand regions.

(Publications)
1. Sanjou, M. and Nezu, I.: Hydrodynamic characteristics and related mass transfer properties in open-channel flows within a rectangular shaped embayment zone, Environmental Fluid Mechanics,will appear, 2013.
2.Sanjou, M., Akimoto, T. and Okamoto, T.: Three-dimensional turbulence structure of rectangular side-cavity zone in open-channel stream, Int. J. of River Basin Management, IAHR, Vol.10, No.4, pp.293-305, 2012.
3. Sanjou, M., Nezu, I. Suzuki, S. and Itai. K.: Turbulence structure of compound open-channel flows with one-line emergent vegetation, Journal of Hydrodynamics, Ser.B, Vol.22, Issue5, Sup.1,pp.577-581, 2010.
4. Sanjou, M. and Nezu, I.: Turbulence structure and coherent motion in meandering compound open-channel flows, Journal of Hydraulic Research, Vol.47, No.5, pp.598-610, 2009.

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