Tomiji Watabe

WAVE POWER EXTRACTION AT COASTAL STRUCTURE BY MEANS OF MOVING BODY IN THE CHAMBER

This report will update the coastal zone practitioner on the National Flood Insurance Program (NFIP) as it affects the implementation of manmade changes along the coastline. It is our intent to place in proper perspective this fast-changing and often difficult to interpret national program. Readers will achieve an overall understanding of the NFIP on the coast, and will be in a position to apply the programs requirements in their efforts. We will begin with a history of the application of the NFIP to the coastal zone. The history of the problems encountered will lead into current regulations, methodologies, and the changes the Federal Emergency Management Agency plans for the future.The spatial variability of the nearshore wave field is examined in terms of the coherence functions found between five closely spaced wave gages moored off the North Carolina coast in 17 meters depth. Coherence was found to rapidly decrease as the separation distance increased, particularly in the along-crest direction. This effect is expressed as nondimensional coherence contours which can be used to provide an estimate of the wave coherence expected between two spatial positions.Prediction of depositional patterns in estuaries is one of the primary concerns to coastal engineers planning major hydraulic works. For a well-mixed estuary where suspended load is the dominant transport mode, we propose to use the divergence of the distribution of the net suspended load to predict the depositional patterns. The method is applied to Hangzhou Bay, and the results agree well qualitatively with measured results while quantitatively they are also of the right order of magnitude.

FAESIBILITY TESTS OF NEW PENDULAR-TYPE WAVE ENERGY CONVERSION APPARATUS

A study of alternatives including a shoreline evolution numerical modelization has been carried out in order to both diagnose the erosion problem at the beaches located between Cambrils Harbour and Pixerota delta (Tarragona, Spain) and select nourishment alternatives.

Studies on a Pendulor Type Wave Energy Converter : Studies on the Efficiency Affected by System's Elasticity

The authors have been studying the Pendulor type energy converter with some excellent merits : -simple, highly efficient, safe and so on, for eight years. This paper deals with the absorbing efficiency of the wave converter affected by the systems elasticity which depends on the deformation of the power members and the compressibility of oil in the power cylinder. The authors investigated the behavior of the elasticity during the operation and explicated the relationship between the efficiency and the elasticity. The deformation by the elasticity and the compressibility reduces the efficiency, as the load ratio increases. To improve this insufficiency effect, appropriate measures are needed. According to these results, several methods for improving the efficiency, including the Pendulors hydraulic circuit and its components, were introduced.

METHOD OF ESTIMATING THE POWER EXTRACTED BY FIXED COASTAL TYPE WAVE POWER EXTRACTORS

More than 150 tests have been analyzed in order to describe the dynamically stable profiles of rock slopes and gravel beaches under wave attack. Relationships between profile parameters and boundary conditions have been established. These relationships have been used to develop a computer program. This program is able to predict the profiles of slopes with an arbitrary shape under varying wave conditions, such as those found in storm surges and during the tidal period.This paper investigates the utility of winds obtainable from a numerical weather prediction model for driving a spectral ocean-wave model in an operational mode. Wind inputs for two operational spectral wave models were analyzed with respect to observed winds at three locations in the Canadian east coast offshore. Also, significant wave heights obtainable from the two spectral models were evaluated against measured wave data at these locations. Based on this analysis, the importance of appropriate wind specification for operational wave analysis and forecasting is demonstrated.