Journal of Waterway, Port, Coastal, and Ocean Engineering

The design of an access channel is based on regulations and recommendations from each country after considering natural and vessel-related criteria and characteristics, always focusing on navigation safety. This paper presents a set of criteria and technical parameters necessary for the planimetric dimensioning, in straight and curved sections, of navigation channels for inland waterways and port access channels, using a computational tool developed and called DimChannel (Channel Dimensioning Navigation), based on the recommendations of the World Water Transport Infrastructure Association (PIANC). The DimChannel was supported by the technical criteria present in recommendations of the PIANC, in which the characteristics of the vessels and waterways adopted in the standard are like the characteristics of Brazilian inland navigation. The software was validated through a case study in the lower Tapajós River, Amazon, Brazil. The results obtained showed that DimChannel is a tool of great importance for the planimetric dimensioning of navigation channels.

A new type of wave energy device has recently been proposed with the key component being a flexible air-filled bag, which is constructed such that the fabric is encased by an array of tendons. The behavior of the bag in still water under hydrostatic loading and its dynamic response when subjected to hydrodynamic loading in waves were previously analyzed using a numerical model developed with the assumption of inextensible tendons. In the present work, the model is extended to include the effects of tendon elasticity. The behavior of the bag with tendons of various moduli of elasticity is then compared with that of the bag with inextensible tendons. It is found that adding elasticity to the tendons has a similar effect to that of increasing the air volume connected to the bag, that is, it increases the resonance period of the device. Consequently, a bag with elastic tendons can be made even smaller in size than a bag with inextensible tendons in order to match the same target resonance period.

The interaction between a solitary wave and a submerged circular plate of a finite thickness was investigated in this study. Analytical solutions based on the linear long wave theory were first derived to serve as the leading-order predictive tool for this physical process. While the analytical solutions provide an easy way to calculate the wave field, they are limited by the simplifying assumptions. To complement the analytical solutions, a 3D Navier–Stokes equation solver with the large eddy simulation turbulence model was employed. The numerical model was verified against the analytical solutions for nearly linear cases and then applied to study more nonlinear cases in which the analytical solutions were less accurate. Both the analytical solutions and the numerical results show that wave focusing occurs near the lee side of the circular plate, creating higher local wave heights than that of the incident wave. As the wave passes over the submerged plate, the plate experiences an uplifting net force, followed by a net force in the downward direction, and then an uplifting net force again. The flow and pressure fields and vortices were also examined. By presenting the analytical and numerical tools that can be used to study this problem, and discussing the overall physics of this process, it is hoped that this study paves the way for future studies on this subject.

Since the 2006 Kuril Islands tsunami, California small craft marinas have sustained over $100 million in total damage from tsunami events. Surveys conducted after the 2006 Kuril Islands and 2011 Japan tsunamis indicated that the mooring systems (e.g., cleats and pile guides) responsible for keeping the vessels and floating docks in place during an event are susceptible to failure. The aim of this paper is to present a risk framework that can be used by decision makers to assess future tsunami risks to small craft marinas. Here, the coupling of high-resolution numerical modeling and an existing statistical framework is extended to include observed damage states for structural elements. When applied to one small craft marina (in Noyo River Harbor), our methodology was able to replicate likely failure, which occurred well below previously identified damage thresholds. The results suggest infrastructure age and condition, in addition to the hazardous tsunami phenomenon, can contribute to cleat and pile guide failure.

Submarine landslides have destroyed many ocean engineering facilities and induced catastrophic tsunamis, causing considerable loss of lives and properties. However, the evolution process of submarine landslides is highly complicated and difficult to describe with a unified mechanical framework. For fluidized landslides with wider influence ranges, faster migration velocities, and stronger impact forces, it is necessary not only to describe the constitutive model but also to determine the flow state. First, based on the essential rheological test for determining constitutive models, the relevant method and principle are thoroughly analyzed, and the formula for calculating the Reynolds number of fluidized submarine landslides in the entire shear process is derived. Taking the critical Reynolds number as the evaluation standard, a methodology to distinguish the flow state (laminar or turbulent) of fluidized landslides is quantitatively proposed. Second, through the low-temperature rheological test, the proposed formula and methodology are briefly applied to the natural submarine sediment samples in the South China Sea. In addition, the point of contraflexure of the rheological curve is consistent with the critical Reynolds number calculated by the formula, and the validity of this methodology is further verified. Finally, the mechanism of the flow-state transition is systematically analyzed by the internal evolution of the structure of the fluidized sediment samples in the shear process. This study provides important support for understanding the migration of fluidized submarine landslides.

The 2011 Tohoku Earthquake and Tsunami generated a massive tsunami that devastated Kujukuri Beach in Chiba Prefecture, Japan. The possibility that edge waves were involved in the propagation mechanism of the tsunami was investigated by using a numerical method. To detect the components of edge waves, the fluctuations of the simulated sea level, the variations of the power spectral and the phase, coherences, as well as the dispersed relations of the wavelength and the period, were analyzed. As a result, it was possible to conclude that there is a high probability that edge waves could have propagated around this coastline. In addition, to analyze the various types of edge waves that could be expected three additional earthquake scenarios were considered, each of them with a different magnitude and epicenter: the 1896 Sanriku Earthquake, the 1677 Empo Boso-oki Earthquake, and the 1703 Genroku Kanto Earthquake. This comparison indicates that there is a particular risk that edge waves can be generated by large earthquakes with their epicenter in the northern part of the Japan Trench.

Exploratory experiments including a series of flume and geotechnical tests were conducted to assess the effects of fines content and relative density on the erosion and recession of predominantly sandy beach and bluff. The beach and bluff were constructed using soils of four fines contents, 0, 5%, 10%, and 15%, at two relative densities of 39% and 68%, and were exposed to varying water levels and wave heights. The results indicated that the increase of fines content reduced the bluff recession rate. This reduction was more pronounced for looser soil, where a 5% fines content resulted in a nearly 24% reduction in the recession rate. The dominant failure mode for looser soils with 0% and 5% fines contents was shear failure. On the other hand, for the bluffs with fines content higher than 5%, as well as those with the denser soil, tensile failure occurred. The data resulted in the establishment of an empirical relationship for the recession rate as a function of fines content and relative density.