The influences of bar and tide on shoreline change were investigated using multiple regression models. The models were applied to the shoreline change on the Hasaki coast in Japan facing the Pacific Ocean measured every workday during a 22-year period from 1986 to 2007, and the model performances were evaluated by AIC (Akaike Information Criterion). The results showed that the outer and inner bar elevations, the maximum tide and the tidal range as well as the offshore wave energy flux and the shoreline position affected the shoreline changes. The shoreline retreated more with the increases in the wave energy flux, the maximum tide and the tidal range, with the decreases in the outer and inner bar elevations, and with more seaward shoreline position.

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In the case where soft bottom mud with high water content over the liquid limit is fluidized by wave-induced pressure, cracks are generated in the surface of the mud. Focusing on the generation of cracks in the mud, a laboratory experiment on the consolidation of soft mud under wave action has been conducted. The characteristics of development of cracks to deeper area are investigated in terms of wave height and occurrence global slip-failure in the mud layer. It is elucidated that consolidation of soft mud is promoted remarkably under wave action because excess pore-water pressure tends to be accumulated around the tips of cracks by wave-induced repetitive shear stress and the pressure dissipates promptly by the drain effect of cracks. Also, the washout of fine particles from deep area of mud has been examined.

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Sediment transport in Ariake Bay is simulated by FVCOM-based numerical model. The sediment flux toward the head of the bay in upper Ariake Bay is reproduced by the model. Variations of sediment flux due to the growth of Chikugo River.'s plume and passing typhoon is also discussed. In addition, the effect of Isahaya Bay\. reclamation on the sediment transport process is discussed. Sediment flux around Isahaya Bay is significantly decreased and it may be the cause of the increasing transparency in lower Ariake Bay after 1990's.

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A numerical model was developed for sediment transport involving suspended load flux which was simultaneously solved with wave fields and current fields around permeable detached breakwaters. The validity of the model was verified through measurements of bathymetry changes in movable bed experiments with the structures conducted in a large wave basin. In the model, increase in friction velocity induced by plunging breaker was introduced which enhanced the erosion inside the surf zone. It is demonstrated that our model fairly reproduced the topography change due to partial standing waves on the offshore side of the structure, rip-current and longshore currents around the permeable detached breakwaters.

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This study investigated the characteristics of mud transport at the ship channel of Miike Port in Ariake Bay, based on field observations and numerical simulations. The findings are as follows: (1) The Suspended Solid (SS) transported from the outside of the port at flood tide is settled down in the channel due to small current, but SS transport is little at ebb tide because of low suspension. (2) The actual settling velocity of the SS in the channel is possibly lager than that in the technical literatures on another part of Ariake Bay. (3) A new observation technique by a slanting radiation of acoustic beams from H-ADCP has clearly confirmed that wave condition in rough sea much affects SS transport into the channel

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The depth of closure determination on Sendai Port and Yuriage Port is predicted using bathymetry data from 1988 to 1998 and 1994 to 1997, respectively. Several cross sections are taken in order to produce longshore variation. Its relation with standard deviation value is also depicted in several cross sections. Wave data collected during 1991 to 2003 is utilized. Boussinesq equation modified by Peregrine (1967) is applied considering its application in non-linear phenomenon. Regular incoming wave is assumed in numerical computation to obtain u_bmax. Furthermore, Shields parameter (τ₀^*) as incipient motion criterion is calculated. The result is confirmed using longshore variation of h_c obtained from bathymetry analysis.

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This study is concerned with the development of a 3D morphodynamic model to sandy beach with shore reef such as exposed rock. The morphodynamics with exposion and buring of the shore reef are reproduced by advection and diffusion model for suspended sediment concentration. Firstly, some model tests were carried out in order to investigate the performance of the presented model. Secondly, the applicability of the presented model was investigated by comparing with the results of sounding survey conducted at sandy beach with shore reef around Sakenotsu fishing port, which is suffering from sedimentation.

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Beach changes between Point Ryugu and Nakoso fishing port facing the Pacific Ocean in Fukushima Prefecture were investigated. The shoreline recession occurred in the study area between 1980 and 1990s was triggered by the construction of the offshore breakwater of Hirakata fishing port south of the coast due to its wave sheltering effect. Although artificial reefs were constructed on the Suga and Sekita coasts in the central part of the study area as a measure against beach erosion, their protective effect was limited because of the high wave sheltering effect of the offshore breakwater of the fishing port constructed at the south end of the coastline.

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Mizushima island located in Tsuruga Bay is a famous recreational beach in Fukui Prefecture. This beach has been eroded in recent years. The topographic changes and tide level changes at Tsuruga Port were measured. On the basis of these field data, the contour-line-change model proposed by Noshi et al. was applied to the prediction of beach changes. It was concluded that beach changes closely relate to the wave action along with the increase in tide level during passage of low pressure in summer.

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On the Ichinomiya coast located in the southern part of Kujukuri Beach, beach erosion has occurred due to the decrease in sand supply from sea cliffs of Point Taito. As a measure against beach erosion, ten artificial headlands have been constructed since 1990. During their construction period, a Taito fishing port breakwater was extended, resulting in change in wave field. Then, the direction of longshore sand transport was entirely changed from north to south because of wave sheltering effect. These beach changes were reproduced numerically using the BG model proposed by Serizawa et al. It was concluded that the artificial headland can be effectively used as a measure for preventing reverse sand transport to the fishing port.

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The instability of the caisson-type breakwater due to seepage of tsunami into the rubble mound and the seabed ground was focused. The breakwater slid due to the action of the initial impulsive force, then shear deformation occurred in the rubble mound and the seabed ground, and the bearing capacity decreased. Subsequently, the hydraulic gradient increased in the breakwater at the shore side due to the continuous wave pressure. The safety factor of the breakwater bearing capacity, which had decreased due to the initial impulsive force, decreased further due to the degradation of the ground caused by an increase in the excess pore water pressure in the ground at the shore side of the breakwater.

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Temporal interactions of shape of rip currents and coastal bathymetry are studied with numerical wave simulation. Boussinesq equations for coastal waves, which involve coastal currents as a solution, are combined with equations of littoral drift and deformation of coastal bathymetry. Uniform slope and the beach cusp with regular spacing are used as typical model coastal geography, and Tayuhama beach located in Niigata city, where the in situ rip current was observed was used as objective of field scale simulation. Results show that interaction between currents and bathymetry change enhances the rip currents more than the case with constant bathymetry. The shepe of rip currents and bathymetry changes obtained by the numerical study agree with theoretical study by Hino.

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Sandbars in the Agano river have seasonal change, such as decay in summer and regrowth in winter basically. In this study, regrowth of the sandbars are simulated with numerical code of interactions among waves, river flows, littoral drift and bathymetrical changes. Multi-directional irregular waves are used for incident wave condition for the purpose of consistency of natural condition. Terrain model was obtained by convert of Agano river mouth bathymetric image to DEM(Digital Elevation Model) data. Numerical results show that deformation of sand bars are strongly affected by river flow discharge and directional conditions of incident wave. The shape of sandbars simulated by the model agrees well with airborne image of terrain of the Agano river-mouth, especially in the left bank of the river.

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In this study, to clarify the temporal-spatial variation of the median grain size on the surface of the sand and gravel beach and its topography change, field observation, spatial analysis and laboratory experiment were carried out. Study site is the east coast beach in the Narugashima Island located between inner bay - Osaka bay - and open sea - Kii channel -. The result of field observation makes it clear that the temporal-spatial variation of the median grain size on the beach is decided by wave, tide and seasonal wind. The result of the spatial analysis shows that the continuity of bed material on the beach in the direction of longshore is more apparent than that of on-offshore. Moreover, the effect of decreasing the blown sand by vegetation on the beach was confirmed in both field observation and laboratory experiment.

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This study highlights erosion of sandy coasts and river mouths in Miyagi Prefecture due to The 2011 Great East Japan Earthquake Tsunami, based on a field investigation and aerial photograph analysis. Mechanism of beach erosion due to the tsunami is classified into three types considering geological formation and coastal structures. Furthermore, complete flushing of sand spit and severe breaching of coastal barrier are observed at several river entrances, which is one of the distinct differences as compared with tsunami disasters caused by The 2010 Great Chilean Earthquake Tsunami. The findings of this study may be useful for preparing for tsunami disaster prevention and preparedness in Japan.

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Artificial sandy beach profiles and the vertical distributions of sediment grain size were measured monthly along one cross-shore line in Azure Maiko Beach for two years. All the measured profiles and vertical distributions are approximated using the quadratic profiles. In order to interpret the temporal variations of the quadratic profiles, six parameters are introduced. The principle component analysis was applied to evolutions of the six parameters to detect major variation modes. The relationships between the detected modes and the external forces, wave height and tidal level, are expressed using the multiple linear regression analysis. The first mode is found to be caused by tidal oscillations and the second by the energetic wave motions. Long term prediction of the modes is examined using these regression results.

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The numerical analysis by LES was carried out for the current and topography change around the Shiogama(namely the deepest region) near Yo Shima. The flow accelerates and diverges radially during the westward current and converges during the eastward current near the top of slope around Shiogama. The anticlockwise vortex is formed at the eastern zone of Mitsugo Shima and this accords with the measured results. During the westward current, the upwelling flow generates near the edge of the slope. So, the suspended sediment cloud which includes the smaller sediment rises up to the sea surface. The numerical result for the suspended sediment coincides with the measured one qualitatively.

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The Irabu Bridge connects Miyako Island to Irabu Island and it is now under construction. A causeway was constructed between the foot of the bridge and its central part using land reclamation method, resulting in formation of wave shelter zone on both sides of the causeway. After the construction of the causeway, marked beach changes occurred on the reef coast, and egg-laying sites of sea turtles were lost. The BG model was applied to investigate the stabilization method of the beach. Most suitable measure was to use groins as well as the beach nourishment.

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The method of improving the accuracy of the prediction of topographic changes along a river delta was investigated, taking the Tenryu River delta as an example. Numerical simulations using the contour-line-change model considering grain size changes were carried out, taking the effects of shoreline curvature, grain size change, ebb tidal currents and wind blown sand into account. Most important factor to improve the accuracy was the effect of the shoreline curvature.

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Long-term topographic changes since 1968 along the entire Shizuoka and Shimuzu coasts with a 17 km stretch extending between the Abe River mouth and the tip of the Mihono-matsubara sand spit were reproduced using the contour-line-change model. Beach erosion of these coasts was triggered by the decrease in sediment supply from the Abe River due to excessive riverbed mining until 1967. After 1982/83 natural sand supply of the river increased and accretion occurred on these coasts. Measured topographic changes were reproduced using the contour-line-change model considering grain size change. Not only the movement of sand body but also the shoreline and bathymetric changes were numerically reproduced. The calculated results were in good agreement with the measured topographic changes.

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On the Fuji coast, fluvial sand supplied from the Fuji River was markedly decreased due to the excessive river bed mining before 1967, causing severe beach erosion. In addition Tagono-ura Port was constructed 6 km east of the river mouth, obstructing eastward longshore sand transport, resulting in downcoast erosion of the port. These beach changes were investigated using past aerial photographs and the shoreline changes were studied. Numerical simulations using the contour-line-change model considering grain size change was carried out to reproduce measured bathymetric changes along with prediction of future beach changes.

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The BG model (a three dimensional model for predicting beach changes based on Bagnold's concept) was applied to the prediction of the three dimensional topographic changes of a sandy island due to waves, which was obtained by a movable bed experiment by Uda and Yamamoto. In Okhotsk Sea, Taketomi Island was formed as an island composed of sand by a volcanic eruption and then, the island was markedly deformed by wave action, resulting in forming a double tombolo behind the island (Zenkovich, 1967). The model was also applied to these topographic changes of the island. The predicted and measured topographic changes in two examples were in good agreement.

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The high-angle wave instability problem defined by Ashton et al. was numerically solved using the BG model proposed by Serizawa et al. The development of sand spits was predicted under the oblique wave incidence that the angle between the direction normal to the shoreline and wave direction becomes larger than 45°, given an infinitesimal perturbation to the initial topography. In this model, not only the shoreline configuration but also three-dimensional topographic changes around the sand spits can be predicted.

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The natural sediment bypassing of river mouth is difficult to determine due to the hydrodynamic complexity in that area. The sediment bypassing of river mouth is one component which important to know and have influence to the behavior of surrounding shoreline. The sediment budget method is applied to determine the sediment bypassing in Nanakita River mouth Sendai Miyagi by using the best known estimated data in that area. The results reveal the existence of sediment bypassing and the role of river mouth to supply sediment to the system. The blocking effects of river mouth to the long-shore sediment transport also indicate in this result. This is important when applying the shoreline change model in the river mouth area.

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Long-term morphological changes of intertidal multiple sand bars are examined using the aerial photographs during 1942 to 2008. Short-term morphological changes of intertidal multiple sand bars also investigated using video image analysis during June to December 2010. Video analysis results are compared with the 3D laser measurements using unmanned helicopter. Although horizontal bar morphology change to some extent under energetic wave motions, their morphology appears to be a permanent feature in both form and position. Sampling the sediment cores in the field, the sediment density and pore profile changes due to one-dimensional (vertical) water pressure are examined using X-ray-CT scanner. The density shows slightly changes during the experiments, however, the pore ratio is less than 0.02.

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Shoreline positions of southern Kashimanada coast facing Pacific Ocean have been observed with 4 X-band radars. The stretch is approximately 17 km long and extending from north to south with Kashima Port at the north and Tone River at the south. Half of the area is protected by coastal structures and the remaining is close to natural beach. Hourly-averaged radar images are processed to observe longshore distributions of shoreline positions and data collected for a year is discussed. The on- and off-shore migrations of shoreline positions are shown which are active for the protected areas and milder at un-protected areas. Waves were estimated with SWAN wave model and relationships between cross shore and longshore energy fluxes and observed changes in shoreline positions are discussed.

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This paper investigates sedimentary characteristics along the west coast of Sri Lanka based on satellite images, feldspar thermoluminescence (TL) and numerical shoreline model. Analysis of aerial photograph and satellite images first revealed significant sedimentation around Kalpitiya, the northern part of the west coast, and severe erosion in the central and southern part of the coast. Monotonous northward decrease of TL indicated the dominant northward sediment transports and also a lack of sediment supply in the central and northern part of the coast. Analysis of ALOS PALSAR data finally captured the more detailed shoreline dynamics around Kalpitiya with frequencies of several months. Based on all these findings, shoreline model was finally applied for predictions of the alongshore sediment budgets.

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Coral cays are low-lying islands formed by coral gravels deposited by the waves and currents on the coral reefs. Cases have also been reported that the coral cays were formed in the short time scales when high waves with storm surges. Once the formation of coral cays can be controlled, which can contribute to the protection, environment and use of the coast on coral reefs and the national land conservation of the Pacific Ocean island nations in danger of inundation by the sea level rise. In this paper, the formation mechanism of the coral cays is verified through hydraulic movable bed model tests and the numerical simulation aimed at Ballast Island in the north of Iriomote Island. As a result, we confirmed that the wave breaking on the reef edge, wave setup, currents, and gravel supplies on the coral reefs exert influence on the formation of coral cays.

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On the Hamaju coast in Fukui Prefecture, beach changes were triggered by large-scale land reclamation and the construction of port breakwater due to their wave sheltering effect. Bathymetric changes were investigated using the past aerial photographs and bathymetric survey data. The effect of beach nourishment using beach materials composed of various grain sizes was predicted by the contour-line-change model considering grain size change, as a soft measure against beach erosion. It is concluded that beach nourishment using coarse sand deposited offshore of the Kuzuryu River is most effective.

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Ibusuki coast has attracted many tourists by its scenic and recreational value, however, recent progress of coastal erosion has resulted in frequent wave overtopping disaster. To avoid interruption of oceanic view by shore protection works, the integrated shore protection system composed of artificial nourishment works and increase of seawall crown height were adopted. DRIM (Distorted RIpple Mat) was also applied for the first time in Japan as a permanent facility to prevent the beach nourishment sand from being washed away. The present study discusses the efficiency of the countermeasure works comprised of DRIM and a groin based on wave observations and field surveys.

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Three sand bags were experimentally installed on the Oiso coast in December 2010 to investigate the effect of short groins for controlling gravel movement on the foreshore. The foreshore changes around these sand bags were measured using a portable laser scanner. During the observation, storm waves with a significant wave height of 4.1 m occurred and significant beach changes were observed around sand bags. Sand bags were effective for depositing gravel around the sand bags.

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A field survey was conducted at Oiso Beach, Seisho Coast, Kanagawa Prefecture. Three geotextile sand packs were placed in order to examine the applicability of sand packs to beach erosion control. Nourishment was introduced together with the sand packs. Frequent high resolution monitoring of beach topography was conducted by using a 3D laser scanner. Development of beach cusps and entrapment of gravels by sand packs were described on the basis of thirteen measurements performed in the period from September 2010 to February 2011. The wavelength of the beach cusp was found to be dependent on characteristics of waves and tides, and shortened by the presence of sand packs. The applicability and limitations of stereo imagery on beach topography monitoring was discussed.

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`Moving Gravel Body' method was developed, in which beach nourishment using beach material coarser than the original grain size of the beach is carried out as a measure against downcoast erosion on a coast with a predominant longshore sand transport. Numerical simulations using the contour-line-change model considering grain size changes were carried out. The effectiveness of the method was shown in comparison with the beach nourishment using fine sand and the installation of concrete blocks.

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Coastal sediment movements and related topographic changes were investigated on the basis of high-frequency and high-resolution topographic survey. The topography around a mound of beach nourishment at the Tenryu River mouth was measured by using a portable 3D laser scanner. High-resolution 10 cm-mesh topographic data were obtained 7 times in a half year. The relationship between volumetric changes of the mound and wave data during the survey was analyzed. It was found that the sediment discharge of a mound of beach nourishment can be estimated quantitatively by the combination of analyses of wave run-up height and the base level height of the mound. A possibility of estimation of sediment size distribution based on a 3D scanner observation was also investigated.

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On Yuyama Coast facing on the sea of Japan, the artificial beach nourishment as the defense work against beach erosions have been conducted. Though the annual nourishments have been carried out, the shoreline is eroded from the autumn to the winter and is restored between spring and summer as the seasonal change. In this study, the experiment was executed for beach profile change induced by the combination of wave type after the beach nourishment. Another series of experiments were performed for following up the nourished sand and the bottom topographic change after the nourishment. The beach profile was measured by laser displacement meter, and the neighborhood of the run-up area was photographed using the fixed point camera. The experimental results show that nourishments using coaser sand in offshore area decrease erosional bottom topographical change.

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Beach nourishment using coarse materials is one of the useful measures against beach erosion. However, its design method selecting the grain size of nourishment materials has not been established yet. To investigate the design method, a large-scale two-dimensional movable bed experiment was carried out using a large flume and the mixture of sand and gravel, and beach profile changes and mixing of sand and gravel were measured.

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In Tomakomai Nishi Port, long-period wave disturbance caused troubles on cargo handling. To reduce these troubles, long-period wave absorbers by rubble-mound structure were designed and the construction was started in 2008. In this study, field observations in the port and numerical calculation were performed to demonstrate the effects of long-period wave absorbers. As a result, there was a tendency that long-period wave height was reduced by the extension of long-period wave absorbers, and the reflection factors of long-period wave absorbers were corresponded approximately to estimated ones in the design.

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Generally, reflection coefficients on the breakwaters and the seawalls covered with wave-dissipating blocks are estimated at from 0.3 to 0.5 for wind waves and swells. The long-period wave absorber which consists of wide-width rubble mound is also designed for the normal direction of incident waves. However, the wave reflection coefficients seem to be reduced for oblique incident waves because an oblique distance is longer than the normal distance in a horizontal wave dissipating work. In this paper, the oblique regular and irregular waves are generated by serpent-type wave maker in a large wave basin and their reflection coefficients in front of wave dissipating works are analyzed with two kind methods. As the incident angle is larger, the reflection coefficients slightly increase for wind waves and swells though they decrease for long-period waves. Moreover, it is verified that such wave reflections can be reproduced in calculations using a Boussinesq-type wave model.

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Numerical simulations on the wave overtopping phenomena were carried out for double seawalls in the Beppu Port by using the numerical model of CADMAS-SURF. The double seawall consists of lower front and higher rear walls and permeable bottom between the two walls. The wave overtopping rates were obtained numerically for various permeability conditions of the bottom and compared with the corresponding experimental results. The comparison confirms good reproducibility of the numerical model in the wave overtopping phenomena. The higher permeability can well reduce the wave overtopping rate, but the reduction effect becomes small for the permeability rate of more than 0.5.

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Sea level change and global warming may cause increasing of external forces due to tides, currents and waves acting on breakwaters. Increase of breakwater weights or additional weight behind of present breakwaters become necessary against such external forces. A counter-weight block is newly developed to increase the resistance against horizontal sliding of breakwaters located at entrance of harbors. In the paper, a physical experiment is carried out to evaluate the friction factor of the counter-weight blocks and to compare with a normal type flat armor concrete block. The friction factor of counter-weight block with rubbles inside the center hole becomes larger than that of the normal one. A simple expectation formula calculating the effect of counter-weight block is proposed according to the experimental result.

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From view point of operation and maintenance, it is a very important issue to survey durability of salt corrosion of coastal structures. Although accurate prediction of quantity of sea spray which attaches surface of coastal structures, the generation process of sea spray when waves attack the structures such as a pier and a sea wall has not been known yet. In this study, conditions of sea spray generation which waves dashing against a vertical wall were found out by laboratory experiments and numerical simulation. Although it is known that the Weber number takes part in the generating mechanism of sea spray, the Ursell number might be used as one of the conditions of sea spray generation. It was re-understood well the most predominant factor as the condition of sea spray generation was the collision velocity of water to a vertical wall.

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An evaluation for exchange of water mass through breakwater with openings is proposed on the basis of the results of hydraulic experiments and numerical simulations. Wave and flow experiments were carried out in hydraulic channel. Three type of breakwater with openings were tested as follow. 1) The caisson with openings at lower part 2) The caisson with openings at the joint part of breakwater 3) The perforated slit caisson with openings at lower part. Hydraulic conductivity was affected by the ratio of the openings with total area of the wall. The 3-D flow numerical simulations(CADMAS-SURF/3D) revealed that the water mass exchanged coefficient can be evaluated. The results of hydraulic experiment show good agreement with numerical simulations.

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In this paper, a 3-D multiphase flow model `DOLPHIN-3D' with solid-gas-liquid phase interaction is utilized to numerically investigate the characteristics of pressure acting on a floating panel, which is installed in front of an upright seawall for wave overtopping reduction. The validity of the model was confirmed through the comparison between the numerical results and experimental ones in terms of the dynamic response characteristics of the floating panel and the pressure at the bottom of the panel. The numerical results revealed that the model can appropriately simulate the pressure acting on the floating panel as well as the dynamic behavior of the panel under wave action.

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The baymouth breakwater is to protect the port area from tsunamis as well as storm waves. A submerged dike is built at the central opening section of the tsunami breakwater to close the bay mouth as much as possible. Because of narrowness, strong current is expected at the occasion of design tsunami attack. The submerged dike consisting of a rubble mound foundation and a crown caisson must be stable against the strong current. The present paper points out stability of the crown submerged caisson on the basis of the result of experiment and numerical wave tank (CADMAS-SURF/3D), and according to these results, verifies the validity of pressure coefficients calculated from hydrodynamic forces.

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In this study, hydraulic phenomenon around wave dissipating blocks is simulated by a three dimensional MPS method with a precise gradient operator and penalty method. This MPS method solves the pressure oscillation and the fluid particle that penetrates through the wall. As an accuracy verification, the authors simulate wave overtopping rate by this MPS method and obtain a similar result compared with two dimensional CADMAS-SURF. In the simulation of wave breaking on seawall of complex shape, the authors obtained good result. The study suggests that this three dimensional MPS is useful to simulate hydraulic phenomenon around wave-dissipating blocks.

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This paper shows the accuracy comparison of wave pressure of tidal bores with the improved MPS and original MPS. The authors simulate two basic tests for verification of accuracy. In the test of progressive wave, the authors show that the attenuation of progressive wave is reduced by the improved MPS. In that of wave shoaling, the atiltness of wave of improved MPS is different from the original MPS. In investigation of wave pressure of tidal bores, the authors show the relationship between the pressure of tidal bore and the bore height. The present study suggests that the improved MPS is useful to simulate wave pressure of tidal bores.

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Deformation analyses of rubble mound as an elastoplastic body have been already carried out, however, in these conventional analyses, large deformation to tilt a caisson on a mound cannot be reproduced. On the other hand, the MPS method used in this study can be applied for such a large deformation, however, in a conventional elastoplastic MPS method, an influence of pore water in a mound cannot be taken into account. Therefore, in this study, an improved elastoplastic MPS method based on effective stress model is developed, and a few fundamental examination of its validity are executed.

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For block-mound construction using barges, it is important for a precise prediction of unsteady motions of settling particles with complicated flow. In this study, high-resolution calculations are implemented by LES with computational grids whose sizes are less than particle diameter. In addition, interactions between both particle-particle and fluid-particle are considered. The validity of the present model and its computational efficiency concerned with grid scale are confirmed by comparing with experimental results and several calculated simulations through behavior of fluid around a settling particle, which is measured by PIV system. An unstedy flow mechanism is exmined by comparing a calculated simulation with a experiment, which is imitated a mound construction using a barge and targeted for motions of multiple settling particles.

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This study describes applicability of a numerical method to local scour by wave action around the pile-supported wave absorbing breakwater. CADMAS-SURF/3D(C-S/3D) was applied to the investigation which was performed by movable-bed models. In the present paper, basic application of CADMAS-SURF/3D was focused, since bottom shape was handled as fixed bed. The verification was achieved by comparing the velocity field of the calculation and the experiment. In the result, simulated value of the mean velocity was good agreement with experimental values, but simulated value of the maximum velocity was greater than experimental values. Moreover, it was not need to take a contracting flow effect by slit consideration in C-S/3D.

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An evacuation port facility for a ferry connecting remote islands is under consideration in Sendai Port. The facility is a rectangular shaped small basin, which consists of wave dissipating vertical walls. The ferry is housed and tightly moored with a number of ropes during severe waves and winds caused by typhoons. To understand the effects of waves and winds on the ship motions and the mooring rope tensions, hydraulic model experiments were conducted. The ship motions were recorded by video cameras and analyzed with motion capture devices. The tension loads exerted on the mooring ropes were measured by load meters connected in rope. It was found that for each mooring rope the maximum tension loads are all less than the rupture load if the rope is new, but when the ropes are deteriorated, the rupture of the ropes might occur.

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