Large-scale experimental study on scour around offshore wind monopiles under irregular waves

The Keulegan-Carpenter(KC)number is the main dimensionless parameter that affects the local scour of offshore wind power monopile foundations.This study conducted large-scale(1:13)physical model tests to study the local scour shape,equilibrium scour depth,and local scour volume of offshore wind power monopiles under the action of irregular waves with different KC numbers.Systematic experiments were carried out with the KC number ranging from 1.0 to 13.0.With a small KC number(KC<6),and especially when the KC number was less than 4,the scour mainly occurred on both cross-flow sides of the monopile with a low scour depth.When the KC number exceeded 4,the shape of the scour hole changed from a fan to an ellipse,and the maximum scour depth increased significantly with KC.With a large KC number(KC>6),the proposed method better predicted the equilibrium scour depth when the wave broke.In addition,according to the results of three-dimensional terrain scanning,the relationship between the local equilibrium scour volume of a single offshore wind power monopile and the KC number was derived.This provided a rational method for estimation of the riprap redundancy for monopile protection against scour.

Factors Associated with District Tsunami Victim Rate by Age Class in Ishinomaki City： 2011 Great East Japan Earthquake and Tsunami

This paper analyzes the factors associated with the district tsunami victim rate in 2011 by age class/group in Ishinomaki city, Japan. Sea or river visibility and evaluation potential from the temporary facilities to higher hills are factors associated with victim rate in addition to tsunami depth. In addition, victim rate, especially for elder people, is low in the districts that have higher aging rate. The characteristics of these districts are： （1） many people are engaged in fishery related jobs and know each other and （2） higher hills are behind the beach.

Life Events,Car Transaction,and Usage by Car Type:Longitudinal Data from Japan

Car transaction(increase/decrease/replacement)is an important determinant of car usage and other travel behavior affecting economic and environmental issues.The aim of this paper is to analyze the impacts of life events,change in attitude,and perceived train frequency on car transactions and usage change by car type using two three-year data(2011-2013 and 2012-2014)obtained from a Japanese household panel survey.We identified the statistically significant factors that affect car ownership in cross-sectional data and verified that their signs are the same when using longitudinal data.Fewer factors are found to affect car replacement than affect car ownership level change.Households that replace Kei-cars with normal cars do not increase mileage.

IMMERSIVE VR VISUALIZATIONS BY VFIVE: PART 2: APPLICATIONS

VFIVE is a scientific visualization application for CAVE-type immersive virtual reality(VR)systems.The source codes are freely available.VFIVE is used as a research tool in various VR systems.It also lays the groundwork for developments of new visualization software for CAVEs.In this paper,we pick up five CAVE systems in four different institutions in Japan.Applications of VFIVE in each CAVE system are summarized.Special emphases will be placed on scientific and technical achievements made possible by VFIVE.