Abstract: This study is concerned with the development of a 3D morphodynamic model for considering wave-current
interaction. The wave action conservation equation for waves and the quasi-3 D nearshore current model with the
surface roller model were employed. Firstly, in order to investigate the influence of the interaction into the
morphodynamics, three model tests associated with a detached breakwater, submerged breakwater and sand bars with
rip-channel were carried out. Secondly, the presented model was applied to the beach evolution after offshore
nourishment, so called “shoreface nourishment”, conducted at the Egmond coast in the Netherland. From the model
tests and the comparison with the field measurement, the validity of the presented model was founded.
Abstract: The development of a numerical model using the fractional area/volume obstacle representation (FAVOR) method for predicting a nearshore current field bounded by complicated geometric shapes, and a three-dimensional (3D) beach evolution was described in this article. The 3D model was first tested against three cases to simulate the nearshore current fields around coastal structures, a river mouth, and a large scale cusp bathymetry. Then, the morphodynamic model tests, which are adopting the nearshore current model, were applied for the computations of beach evolution around a detached breakwater and two groins. It was confirmed that the presented model associated with the FAVOR method was useful to predict the nearshore current field in the vicinity of the complicated geometric shapes. Finally, the model was applied to a tombolo formation in a field site of Kunnui fishery port, which is located in Hokkaido, Japan.
Abstract: A numerical model was developed for simulating a three-dimensional multilayer hydrodynamic and thermodynamic model in domains with irregular bottom topography. The model was designed for examining the interactions between flow and topography. The model was based on the three-dimensional Navier-Stokes equations and was solved using the fractional step method, which combines the finite difference method in the horizontal plane and the finite element method in the vertical plane. The numerical techniques were described and the model test and application were presented. For the model application to the northern part of Ariake Sea, the hydrodynamic and thermodynamic results were predicted. The numerically predicted amplitudes and phase angles were well consistent with the field observations
Abstract: This paper focuses on the sensitivity analysis of various design parameters for heavy-duty
pavement for container terminal areas using Airport Pavement Structural Design System (APSDS) to yield an optimal design solution. APSDS is based on layered elastic theory, which was introduced into airfield design practice with the release of the computer program LEDFAA (Layered Elastic Design, Federal Aviation Administration). In this study, the effects of lateral wandering distribution, container weight frequency, design life, variation of elastic modulus for concrete block pavers and sub-grade, changing the handling system, and changing the interface conditions at the bottom of base layer on the pavement design were carried out. Also various construction materials were used and several combinations of base and subbase
materials were analysed to be able to select the most economical pavement structures.
Abstract: This study develops a three dimensional morphodynamic model around coastal structures considering a wave-current interaction. In the wave model, the current effects on wave breaking and energy dissipation are taken into account as well as the wave diffraction effect. Furthermore, the nearshore current model was modified in association with the surface roller effect. Firstly, an experimental data set from the Large Scale Sediment Transport Facility was used to evaluate the predictive capability of the model. Secondly, several model tests against detached breakwaters were carried out to investigate the performance of the model. Finally, the model was applied to Kunnui fishing port for the prediction of the bathymetry after 1 year, and for the calibration and verification of the morphodynamics around the coastal structures. For the model tests, the performance of the model was investigated; and for Kunnui fishing port, the model result shows a good agreement with the field observation. It was found that the wave-current interaction with the surface roller was significantly playing an important role in the prediction of the three dimensional morphodynamics computation.
Abstract: This article describes the development and application of a three dimensional (3D) multilayer hydrodynamic model of tidal motions and thermohaline circulation. The governing equations were derived from 3D Navier-Stokes equations and were solved using the fractional step method, which combines the finite difference method in the horizontal plane and the finite element method in the vertical plane. The 3D model was first tested against the density current test in order to investigate the performance of the model. Then, the model was applied to the northern part of the Ariake Sea. In the model test, the results of density current were agreed qualitatively with the performance of salt intrusion. In the model application, the hydrodynamic and thermohaline circulation are
predicted. The computed amplitudes are agreed within ±3% compared with the observations, and the phase angles agreed well with the observations. The phase angle results were improved when the thermohaline circulation was considered in the computations as compared with the results without the thermohaline consideration. The tidal currents for the Ariake Sea form a round-trip style during the flood and ebb tides. The numerically predicted results show good agreement with field observations of tidal currents, and they improved after considering the thermohaline circulation.
