Journal of Waterway, Port, Coastal, and Ocean Engineering

Fluid impact forces on a bridge superstructure in the horizontal and vertical directions due to tsunami inundation, represented by a solitary wave, were investigated through a large-scale laboratory experiment and numerical simulations. The experiment was conducted in a two-dimensional large wave flume using a 1:5 scale steel girder and concrete slab bridge model, tested under shallow water waves at two water depths. Wave forces measured in the experiment were used to validate and assess the numerical predictive capability of a nonlinear hydrodynamic model. A numerical parametric study was conducted to determine the effect of variations in bridge elevation and wave height on the magnitude of the horizontal and vertical forces and overturning moment. Finally, an improved simplified design procedure based on the experimental and numerical results is proposed.

A ship moving across a shallow depth change, in water in a small or narrow space, may create a small tsunami, 0.5–1 km long, observed as a harbor wave on shore, where a wave height up to 1.4 m has been measured. The paper gives an interpretation of the generation process of this new phenomenon. At a depth change, the ship-induced fluid velocity produces a reaction velocity of equal magnitude and opposite direction, orthogonal to the bottom. This velocity appears as a vertical velocity at the water surface, making the waves. The waves propagate with the shallow water speed upstream of a ship moving at subcritical speed. Theory and numerical calculations for a real ship geometry are compared with a moving pressure distribution. Computations compare favorably with a few available wave height measurements.

Bathymetric data plays a major role in obtaining accurate results in hydrodynamic modeling of rivers, estuaries, and coasts. Bathymetries are commonly generated by spatial interpolation methods of data on a model grid. Sparse and limited data will impact the quality of the interpolated bathymetry. This study proposes an efficient spatial interpolation framework for producing a channel bathymetry from sparse, cross-sectional data. The proposed approach consists of three steps: (1) anisotropic bed topography data locations transformed to an orthogonal and smooth grid coordinate system that is aligned with its riverbanks and thalweg; (2) sample data are linearly interpolated to generate river bathymetry; and (3) the generated river bathymetry is converted into its original coordinates. The proposed approach was validated with a high spatial resolution topography of the Tieu estuarine branch. In addition, the proposed approach is compared with other spatial interpolation methods such as ordinary kriging, inverse distance weighting, and kriging with external drift. The proposed approach gives a nearly unbiased topography and a strongly reduced RMSE compared with the other methods. In addition, it accurately reproduces the thalweg. The proposed approach appears to be efficiently applicable for regions with sparse cross-sections. Moreover, river topography generated by the proposed approach is smooth including important morphologic features, making it suitable for two- and three-dimensional hydrodynamic modeling.

Tidal flow has a significant influence on the mooring safety of vessels in deep-sea ports. In order to ensure the mooring safety of vessels, improving the structure form of the wharf can decrease the tidal effect, especially the transverse flow effect. In this study, a distorted tidal model test has been performed and two structural forms of pile-supported wharf (with or without pile wall) have been considered. Based on the measured flow velocity and flow direction, the influence of the pile wall on the fluid field around the pile-supported wharf has been investigated. In general, the pile wall has a significant effect on the tidal flow velocity, the transverse flow velocity, and the ratio of transverse flow. However, compared with the obvious decrease of the transverse flow velocity and the ratio of transverse flow, setting the additional pile wall has a smaller reduction effect on tidal flow velocity. In addition, a cumulative frequency distribution of the ratio of transverse flow is performed, and for a specific cumulative frequency value, the ratio of transverse flow is smaller after equipping the pile wall.

In the past, hydraulic and structural design has predominantly relied on deterministic methods, often neglecting the stochastic nature that underlies transient loading processes. Nowadays, probabilistic design methods have gained wider attention. The accurate estimates of design conditions for structures must consider the probabilistic properties of the loads. One of the more challenging loads in extreme flooding events is related to debris transport and loading during hydrodynamic hazardous events. While it is crucial to assess damage on infrastructure as part of the design cycle, field surveys and numerical modeling provide little guidance as to how the motion of debris within these natural disasters can be adequately captured. This study examines an idealized case regarding the transport of debris during extreme flooding events, by evaluating the characteristics of shipping container motion entrained in a dam-break flow over a flat, horizontal bed. In aiding the promotion of probabilistic methods, this study proposes characteristics of the stochastic properties of debris transport, focusing on the lateral displacement and velocity of debris based on the experimental results. The magnitude of the lateral displacement was shown to strongly correlate with the local hydrodynamic conditions and the initial configuration of the debris. The results of the physical model were then incorporated into a probabilistic framework. The aim for developing this framework is to facilitate debris hazard assessment in extreme flooding event studies.

In previous numerical simulations of local scour, the steady flow is normally adopted as the inlet boundary condition, and the approach flow is always assumed as a homogeneous isotropic turbulence. In the present study, the results turn out to be different from such previous cases, even without obstructions. Under conventional methods, the approach flow decays along the streamwise in the computational domain. Meanwhile, in order to ensure the simulation effect for some major projects such as the local scour around bridge piers and submarine pipelines, appropriate inlet boundary conditions and its self-sustaining character become some of the important factors. Therefore, in the present study, a novel self-sustaining model with the standard k-ɛ turbulence model is proposed to quickly obtain a homogeneous isotropic turbulence. The model parameters are discussed in the light of flume experiment data by sensitivity analysis. To verify the applicability of the proposed model and inlet boundary conditions, numerical simulations in an empty domain are also performed. It is shown that the novel self-sustaining model and corresponding inlet boundary can produce a homogeneous isotropic turbulence, which will help to guarantee fine numerical simulations for scour prediction with prescribed flow conditions.

Aggregation state significantly influences the size, density, and transport characteristics of fine sediment. Understanding sediment transport and deposition processes in the nation's navigable waterways is a primary mission for the US Army Corps of Engineers (USACE), particularly when it comes to infilling of navigation channels. In this study, a newly developed camera system was used to evaluate the aggregation state of eroded sediment from cores collected in the tidal James River, VA. Results showed that bed sediments were composed mostly of mud, but that erosion predominately occurred in the form of aggregates with median sizes 50–270 times larger than the disaggregated sediment. Aggregate size weakly correlated to shear stress at levels <2 Pa, as well as sand content and bed density. A numerical simulation demonstrated that mud aggregates were predicted to transport in incipient suspension or bedload, while disaggregated fines were predominately maintained in full suspension. This difference in transport mode has significant implication for channel infilling and sediment transport within the system.

Recent studies show that many of the extreme events in hydrology can be modeled more realistically by means of a nonstationary generalized extreme value (GEV) distribution. However, existing approaches for estimating the parameters can mistake a positive trend in the data to be negative. This can lead to underdesigning in engineering projects. To address this issue, this work devises a sign constrained Bayesian inference method for nonstationary GEV distributions. This new approach ensures that the final GEV model embodies a trend consistent with the physical understanding of the underlying phenomenon and design requirements. The advantage of using the sign constrained Bayesian approach is twofold: first, it produces a probability distribution instead of a point estimate of the model parameters; and second, it affords a natural method of uncertainty quantification, thus giving greater confidence to engineers in selecting design parameter values for civil and mechanical structures to withstand extreme events. The merit of the proposed Bayesian approach is illustrated using two water level datasets pertaining to tidal rivers in New Jersey. The results show that the new method is capable of appropriately handling datasets for which traditional methods return a positive or negative slope in the location parameters, and produces the posterior distribution of the parameters based on the observed data and not point estimates. Further, the availability of a probability distribution for the return event gives engineering designers and planners additional information and perspective on the risks involved.

For the first time, hydrodynamic parameters such as damping coefficient, added mass, and the natural and resonant frequency of a bottom-fixed oscillating water column (OWC) are determined for various underwater chamber openings and orifice sizes by performing physical experimental free decay tests and utilizing logarithmic decrement method. The damping coefficient of the system is found to be exponentially and linearly decaying as the orifice size increases and underwater opening decreases, respectively. The determined damping coefficient also includes the viscous losses under the front wall opening of the OWC system. The water column within the chamber is modeled as a single degree of freedom (SDOF) mechanical system, and obtained damping and added mass values are substituted into the model. The surface water column displacements are determined by both solving the developed model and performing physical experiments under the generated monochromatic incident waves. A remarkable agreement is found between the analytical model results and the physical experimental data when the water column surface acted approximately as a rigid body. However, when a significant amount of sloshing occurs in the chamber, model results diverged from the experimental values. It was observed that relatively high power take-off (PTO) damping and small chamber openings substantially restrain the sloshing motion otherwise inherently generated in the chamber. In addition, for all openings and orifice sizes used in this study, the determined resonant frequencies of the OWC matched well with those obtained from the experimental data.

The applications and computational capability of the three-dimensional transient numerical panel code ITU-WAVE using potential theory approximation is further extended for the effects of the multibody interactions in arrays with linear and square arrays. The transient wave-body interactions of first-order radiation and diffraction hydrodynamic parameters are solved as the impulsive velocity potential to predict impulse response functions (IRFs) for each mode of motion. It is shown that hydrodynamic interactions are stronger when the bodies in an array system are in close proximity and these hydrodynamic interactions are reduced considerably and shifted to larger times before decaying to zero when the separation distances are increased. The numerical predictions of the radiation (added-mass and damping coefficients) and exciting (superposition of diffraction and Froude-Krylov) forces are presented on each floating body in an array system and on a single structure considering array as a single floating body. Furthermore, the numerical experiment shows the hydrodynamic interactions are more pronounced in the resonant frequency region that are of important for fluid forces over multibodies, responses, and designs of multibody floating systems. The present numerical results of ITU-WAVE are validated against analytical, other numerical, and experimental results for single body, linear arrays (two, five, and nine floating bodies), and a square array of four truncated vertical cylinders.

Ship–bank collisions linked to strong wind and ship–bank interaction pose a great threat to ships with large windage areas in restricted waters. In the analysis of ship–bank collision probability, maneuvering simulations with reasonable estimates of wind conditions and ship routes are important but have had little investigation. This paper presents a maneuverability-based analytical approach for evaluating the probability of a container ship colliding with a channel bank under strong wind. The Monte Carlo simulation technique is applied to conduct numerous runs of the maneuvering simulation. The steady state equations of ship motion and the time-domain simulation method are combined in this approach to detect a ship–bank collision. The input data for the simulation including wind speeds, wind directions, and ships' positions relative to the channel centerline are obtained from the meteorological data and the Automatic Identification System. The proposed approach is applied to a probabilistic analysis of a 10,000 TEU container ship entering Yangshan port, and discussion is given on the feasible ship speed and stacking configuration for reducing the probability of ship–bank collisions.

Scour erosion processes can occur at seabed level around offshore wind turbine monopile foundations. These scour processes are often especially severe at sites where mobile sediments, such as sands, are present in the superficial seabed soils. Loss of local soil support to the monopile, caused by scour erosion, can lead to significant changes in the dynamic characteristics of the wind turbine support structure. This can result in accelerated fatigue damage, owing to the applied cyclic loads from the wind turbine generator, especially at the rotor frequency. Although scour erosion can be controlled by appropriate scour protection systems, there is a lack of knowledge to support the design and optimization of these protection measures, to ensure that the dynamic performance of the wind turbine support structure remains within acceptable limits. This paper describes an experimental campaign conducted on a 1:20 scale model of a driven monopile foundation and wind turbine support structure, founded in a prepared sand test bed in the Fast Flow Facility flume (HR Wallingford, UK). Scour processes were induced by applying cycles of flow. Experiments were conducted to investigate the influence that these scour processes, and selected concepts for preventative and remedial scour protection, have on the dynamic characteristics of the monopile–tower system. The paper describes the experimental procedures that were adopted, and provides an assessment of the results.

Despite the widely recognized role of infragravity (IG) waves in many often-hazardous nearshore processes, spectral wave models, which exclude IG-wave dynamics, are often used in the design and assessment of coastal dikes. Consequently, the safety of these structures in environments where IG waves dominate remains uncertain. Here, we combine physical and numerical modeling to: (1) assess the influence of various offshore, foreshore, and dike slope conditions on the dominance of IG waves over those at sea and swell (SS) frequencies; and (2) develop a predictive model for the relative magnitude of IG waves, defined as the ratio of the IG-to-SS-wave height at the dike toe. Findings show that higher, directionally narrow-banded incident waves; shallower water depths; milder foreshore slopes; reduced vegetated cover; and milder dike slopes promote IG-wave dominance. In addition, the empirical model derived, which captures the combined effect of the varied environmental parameters, allows practitioners to quickly estimate the significance of IG waves at the coast, and may also be combined with spectral wave models to extend their applicability to areas where IG waves contribute significantly.

The lateral bearing performance of a defective pile-supported wharf located on a slope was investigated through centrifuge modeling, and a numerical model was employed to back-analyze the centrifuge test data. The pile foundation system was composed of double-plumb, single-plumb, and batter piles, and the defects were located at the front row of the double-plumb piles. The failure mode, bearing lateral load, bent displacement, and pile bending moments were examined. The results show that overturning with slight torsion occurred in the bent under the lateral load. The piles clearly deformed around defects and were separated from the soil on the landside. The lateral bent displacement increased rapidly after a threshold lateral load value was reached. The bending moments were generally positive (i.e., the side facing the water was in tension) in the upper parts and negative in the lower parts of the double-plumb piles. The bending moments of the double-plumb pile heads increased with the lateral load, whereas the bending moments directly underneath the slope surface exhibited decreasing-constant tendencies with increasing lateral load. The bending moment of the single-plumb pile was generally positive above the slope surface and in compression below the slope surface, and decreasing-constant tendencies were observed with increasing lateral load just below the slope surface. The bending moment of the forward batter pile was negative and decreased with the lateral load around the slope surface and in the middle of the soil. The bending moment of the backward batter pile was generally positive above the slope surface, negative below the slope surface, and remained almost constant around the soil.

This study aims to gain insights into turbidity currents in approach channels with a closed end. A vertical two-dimensional numerical model was introduced, which considers the viscosity of sediment and assumes rheological behavior of the very near-bed layer. The dynamic propagation of the turbidity current, both before and after it reaches the closed end, was studied. It is found that before the turbidity current reaches the closed end, the velocity of the current head is unaffected by the length of the channel, while the velocity and height of the turbidity head are decreased along the channel. When the head reaches the wall, a surge and reverse flow occur. After a quasi-stable state has formed, results show that the speed of current along the channel decreases gradually to zero speed at the closed end. The current speed increases asymptotically with the initial sediment concentration toward a limiting value at high concentrations. The depth of the turbidity current is about 0.3–0.6 times the total depth. The sediment concentration is reasonably constant along the channel. The study deepens the understanding of turbidity currents in these special channels and provides theoretical guidance for engineering practice.

This work aims to enhance the evidence base of extreme impact loads on the front (outer) wall and within the chamber of an oscillating water column (OWC) integrated into a vertical breakwater. Data are from large-scale physical model tests (at 1:9 scale) at the large wave channel (GWK). The paper shows that established prediction methods for nonimpulsive and impulsive wave loads for conventional vertical breakwaters can be applied to the front wall of OWC breakwaters. For the first time, impact loads within the OWC chamber have been quantified, on the rear in-chamber wall and on the chamber ceiling. These are found to reach magnitudes comparable to front wall wave impacts. Novel video records from within the OWC chamber provide new insight on water column behavior, including three different classifications identified as “single,” “successional,” and “water column” ceiling impacts. Conditions at risk of violent impacts within the chamber are also identified. These will be valuable in quantifying front (outside) design forces, in-chamber impacts, and in seeking to minimize in-chamber impacts occurrence, in construction and in operational phases.

The climate change induced by global warming is predicted to change the rate of sea level rise (SLR) and that of shoreline shifts. In this study, the SLR as well as the resulting retreat of shorelines has been predicted at a series of locations along the Indian coastline to understand the future of India’s beaches. The beach segments near 13 major ports where increasing infrastructure requirements are likely to arise in future are considered. The future SLR is predicted on the basis of an ensemble of general circulation models corresponding to stabilized and worst-case global warming scenarios. This showed that the rate of absolute SLR would be in the range 3.38–5.16 mm/year with a mean of 4.56 mm/year for the stabilized scenario called representative concentration pathway (RCP)-4.5 and 5.36–7.2 mm/year with a mean of 6.63 mm/year for the worst-case RCP-8.5 at the selected locations. The maximum rate of SLR could be experienced near the New Mangalore port area while the minimum could be seen near the Chennai and Ennore ports. Additionally, Cochin and Tuticorin ports could also experience the same SLR as the New Mangalore port for the RCP-8.5 scenario. The shoreline recession in response to SLR was evaluated using Bruun’s rule. The results of Bruun’s rule indicated that the future recession of shorelines at selected coastal stretches might vary between 14.10–29.22 m and 21.05–45.40 m up to the year 2100 for RCP-4.5 and RCP-8.5 respectively. Similarly, by this time, area-wise maximum horizontal inundation could happen near the Mumbai port region, although it is the Port Blair area where the maximum percentage increase in horizontal inundation could be experienced for both the scenarios. In general, as compared to the west coast locations, the east coast sites would undergo smaller area inundation due to relatively lower SLR and resulting shoreline change.

This study develops a site-specific analysis of sediment transport for the in-the-wet construction of Olmsted Locks and Dam on the Ohio River using the HEC-RAS model. Results from the analysis are used to assess the frequency of need for dredging. Toffaleti's sediment transport function is used herein and is calibrated to the United States Army Corps of Engineers (USACE), Louisville District measurements of sediment concentrations. We apply the calibrated model to historical river flow along the excavated portion of the streambed, during dam construction. We make predictions over a simulation period for deposition in the excavated area without considering the shell placements that are actually made or any dredging to remove deposited sediment. One notable trend on sediment deposition in the excavated area is that approximately half of the long-term predicted deposition occurs within the first six months. Our results show that trapping efficiency of the transported sediment load follow a similar trend starting at less than 10% and dropping to 1% within a half a year. The results of this analysis are useful for other planning dredging operations where in-the-wet construction will be performed.

Category 5 Hurricane Michael made landfall near Mexico Beach, Florida on October 9, 2018, with measured high water marks (HWMs) reaching 7.2 m NAVD88. The town itself received great damage, with many areas destroyed down to the foundations. In this study, we document the storm and its effects on the greater Mexico Beach area: hazard, structural damage, and their relationships. Wave and surge damage was nearly total for low-lying properties, but damage decreased greatly with increasing elevation. Major wave and surge damage was noted in Federal Emergency Management Agency (FEMA) X zones, which are out of the 100-year floodplain, and it is suggested that the 100-year storm is a deficient measure for categorizing flood risk.

Tampa Bay, FL, is a large, ecologically rich estuary that hosts one of the largest commercial ports in Florida. Automatic identification system (AIS) records from 2015 to 2017 were used to determine the number, size, speed, type, and transits of vessels in Tampa Bay. The AIS vessel types were grouped into 10 general classes based on function. The cargo and tanker classes had the highest number of unique vessels transiting the estuary. The tug class had the highest number of individual transits, followed by cargo class. The most common vessel lengths were 165–200 m. Typical drafts were 9–11 m, and ship speeds were almost all <10 m/s. Froude numbers calculated from these data indicated that ships were generally underway in displacement mode. Overall, <0.1% of the AIS records reported speeds >10 m/s. These were identified as smaller passenger and recreational vessels operating in planing mode. The AIS navigational status and speed were often inconsistent, therefore, the combination of speed and duration was used to define individual transits. The average tidal dependency (TD) parameter for all vessels transiting into the bay was −0.02, and 0.10 for combined cargo and tanker vessels. Proper evaluation of the TD required inclusion of the phase lag between the entrance position and the tide gauge.