Journal of Waterway, Port, Coastal, and Ocean Engineering

The ship-generated waves in restricted waterways can influence the behavior of sediment resuspension and bank erosion. This paper explores the case study considering the effect of ship-generated waves in restricted channels. A fully nonlinear Boussinesq model (FUNWAVE-TVD) is used to simulate the ship-generated waves. The sediment transport model adopted in FUNWAVE has been changed to incorporate the modified diffusion coefficients, deposition flux, and an explicit equation for settling velocity and critical shield parameter. The sediment transport model was validated against the experimental results of solitary waves in a wave tank, and model performance in shoreline geometry was reported. The implementation of the moving vessel in the numerical model and its impact on suspended sediment concentration were evaluated against the field measurements in the Falta stretch of the Hooghly river in Indian National Waterway 1. The error value in predicting the depth-averaged suspended sediment concentration by the FUNWAVE module was 97.6%, which has been significantly reduced to 16.3% based on the present modification. The parametric study of the ship waves in a typical restricted waterway of India revealed that the concentration of the sediments gradually decreases from the navigation channel to the river banks due to dissipation in the ship waves. The change in wave height and depth-averaged sediment concentration increases with the increasing depth Froude number. Finally, the impact on sediment transport due to different scenarios, such as the movement of two vessels in close proximity, the passage of vehicles coming from the opposite direction on the navigation channel, the influence of small draft vessels, and the bed morphology changes due to the multiple vessel movements are analyzed and reported.

Multimechanism floods (MMFs) are caused by the simultaneous occurrence of more than one flood mechanism such as storm surge, precipitation, tides, and waves. MMFs can lead to more severe or differing impacts than single-mechanism floods. As a result, comprehensive risk assessments require the ability to assess the multivariate probabilistic behaviors of hazards from MMFs. This study introduces a novel Bayesian-motivated approach for the probabilistic assessment of hurricane-induced hazards from the combination of the surge, precipitation, tides, and river antecedent flow. A Bayesian network (BN) is developed to capture the physical (conditional) relationship between variables and facilitate the generation of a hazard curve for river discharge that captures the contributions from multiple flood drivers. A case study located along the Delaware River is used to illustrate the proposed approach. Five computationally efficient representative predictive models are developed to estimate the conditional distributions required for the BN as a means of demonstrating the overall framework. The predictive models used in this study act as placeholders and can be replaced with more sophisticated and high-fidelity models depending on the desired accuracy level. While the predictive models are intended to be representative and illustrative, the model performance is evaluated using three historical storms that affected the area. Overall, the proposed framework is shown to be transparent, effective, and adaptable.

Concept design guidelines for ship turning basins are often not met in practice due to environmental, economic, or geotechnical restrictions. In these cases, a detailed design procedure is followed to develop an optimized turning basin geometry within the environmental constraints. Then, real-time ship maneuvering simulations are used to evaluate the maneuvers in the proposed geometry. However, such a detailed design procedure is costly, especially if a large number of simulations are required. To restrict the number of simulations, the waterway authority [Voies navigables de France (VNF)] ordered a study to find a generic and optimal design for a turning basin which could be suitable for the upgrade in the northern part of their inland waterway network. Therefore, the turning maneuvers for two typical inland navigation vessels were simulated in real time under different hydrometeorological conditions. This study was conducted in three stages. First, maneuvers in traditional circular and trapezoidal turning basins of different sizes were executed and analyzed. Second, optimized turning basin geometries were developed. Finally, the turning maneuvers in those optimized geometries were analyzed. Based on the results of this analysis, a stepwise approach was proposed to select an optimized turning basin geometry that was based on the conditions present on site. This stepwise approach for the design of turning basins could reduce the real-time simulations that are required when upgrading a waterway network.

The hydrodynamic characteristics of fixed floating structure (FFSs) of various configurations, such as rectangular fixed floating structures and trapezoidal fixed floating structures coupled with submerged breakwaters of two different shapes, namely, rectangular breakwater and trapezoidal breakwater, are investigated using the multidomain boundary element method under the framework of small-amplitude wave theory. The hydrodynamic analysis of the FFS with and without the presence of submerged breakwater is performed for the variation in physical parameters such as a change in structural parameters of the submerged breakwater (shape, relative submergence depth, relative crest width, and structural porosity), structural parameters of FFS (shape and structural width), wave parameter (angle of incidence), and relative spacing between the FFS and submerged breakwater. The study demonstrates, for a given range of incident wave angles, periodic values of the distance between the submerged breakwater and the FFS and optimal shape combinations for which the coupled structures act effectively in attenuating wave force acting on the FFS and optimizing wave transformations. In addition, to enhance the hydrodynamic performance, the presence of reef structures in front of the FFS is associated, which results in Bragg’s resonance with a phase shift in peaks of wave reflection and transmission coefficient caused by changing the structural porosity of the submerged breakwater, indicating that the proposed models are more flexible, allowing demand-based control over shore dynamics and coastal management. The study will be useful for coastal management and safeguarding floating structures by selecting various forms and combinations of coupled FFSs with submerged porous breakwaters.

The wind effect on the efficiency of a coastal defense structure is studied in this paper. It is normally assumed that the strength of the wind impact is characterized by the impulse parameter. If it is lower than a certain value, the wind is expected to have a dominant effect on the wave overtopping rate. In contrast to the regular observation, this study reports a new regime of wave overshoot when a low value of the impulse parameter does not lead to increased importance of wind. It is argued that the new regime appears due to the triplet instability previously studied by others. The variation of the standing wave height and the overshooting jet between the sequential cycles results in independence of the overtopping rates of the wind speed.

The preferred foundation type for offshore wind is still monopile foundations due to the relative ease of design, manufacturing, and installation. The wave loads (between seabed and wave crest) on present-day monopile foundations are inertia-dominated with Keulegan–Carpenter numbers rarely larger than 6–10. The design of foundations include external environmental factors such as aerodynamic loads on tower and blades, Morison-type loads due to waves and current, and slamming loads from breaking waves; however, the literature, international standards, and guidelines have so far ignored the loads on the monopile due to pore pressure in rigid or elastic soil skeletons. The present work will show that the loads due to pore pressure are intimately linked to the inertia wave loads in the water column (above the seabed). The loads will be quantified with a simple engineering approach including diffraction effects from regular and irregular waves, where the soil skeletons are considered as (i) rigid with incompressible pore water and (ii) elastic with partially saturated, compressible pore water based on the quasi-static formulation of the Biot equations. The importance of this new force contribution to the total hydrodynamic force is discussed as well as its importance for design of monopile foundations.

In a laboratory experiment, air could be encapsulated inside a small port of a pressure transducer located in front of a sensing chip during water action on a structure, which may induce extra but unwanted air pressure, leading to inaccurate measurement of the desired water-induced pressure. In this study, both the ported and the deported pressure transducers are applied to the wave-pressure measurements regarding sinusoidal and solitary wave experiments. The present result shows that the influence of encapsulated air inside the transducer port can generally result in an underestimation of the measured water pressure. Accordingly, deported-type pressure transducers are recommended for the water-induced pressure measurement, especially in a small-scale laboratory experiment.