Journal of Waterway, Port, Coastal, and Ocean Engineering

Modeling and analysis of the statistical patterns of vessel interarrival time is a crucial research area for port planning and is also the basis of port capacity analysis and simulation-related works using theoretical queuing methods. This study seeks to identify probabilistic models of vessel interarrival time for a single berth. Two generalized queuing models (GQMs), gamma-GQM and lognormal-GQM, were proposed and tested by a novel hybrid parameter estimation method. To test the proposed models, detailed records of vessels entering Tianjin Port between 2012 and 2014 were utilized; nine berths consisting of three types—bulk cargo, container, and crude carrier—were chosen and studied. The results of the study show that (1) single models are unsatisfactory for single-berth interarrival time modeling in most cases, whereas the proposed mixed models provide much better overall goodness of fit; (2) the statistical properties and the proportion of congested interarrival time are highly related to traffic intensity; (3) the lognormal distribution model performed the best of all tested single models, and the lognormal-GQM performed the best of all tested models.

Storm surge and overland flooding can be predicted with computational models at high levels of resolution. To improve efficiency in forecasting applications, surge models often use atmospheric forcing from parametric vortex models, which represent the surface pressures and wind fields with a few storm parameters. The future of storm surge prediction could involve real-time coupling of surge and full-physics atmospheric models; thus, their accuracies must be understood in a real hurricane scenario. The authors compare predictions from a parametric vortex model (using forecast tracks from the National Hurricane Center) and a full-physics coupled atmosphere-wave-ocean model during Hurricane Isaac (2012). The predictions are then applied within a tightly coupled, wave and surge modeling system describing the northern Gulf of Mexico and the floodplains of southwest Louisiana. It is shown that, in a hindcast scenario, a parametric vortex model can outperform a data-assimilated wind product, and given reasonable forecast advisories, a parametric vortex model gives reasonable surge forecasts. However, forecasts using a full-physics coupled model outperformed the forecast advisories and improved surge forecasts. Both approaches are valuable for forecasting the coastal impacts associated with tropical cyclones.

Considering the limitations of previous calculation methods for the throughput capacity of coal export terminals, this paper proposes a new analysis method for terminal throughput capacity on the basis of a computer simulation model. The simulation analysis model was built considering many certain factors, such as terminal layout, a loading and unloading process scheme, equipment efficiency, and several uncertain parameters, such as the frequency of ships to the terminal, frequency of trains going to the terminal, and shiploads. The simulation model has two characteristics. First, to describe the status of it more accurately in the model, a coal stockyard was divided into small grids. Second, two logical structures for the model are proposed in this paper: the train arrival plan that was informed by the ship arrival plan, and the ship arrival plan and the train arrival plan, which are independent of each other. Applying the simulation model to a coal terminal shows that the error between the calculation results and the actual throughput is very small, thus verifying the accuracy of the analysis method. The model can be used not only to calculate the throughput capacity of a coal export terminal but also to analyze capacity changes for varying storage times, shiploads, and frequencies of ships going to the terminal.

In this paper, selected results are presented from a set of recent full-scale trials measuring the dynamic sinkage, trim, and heel of 16 container ship transits entering and leaving the Port of Fremantle, Western Australia. Measurements were made using high-accuracy Global Navigation Satellite System (GNSS) receivers and a fixed reference station. The measured dynamic sinkage, trim, and heel of three example container ship transits are discussed in detail. Maximum dynamic sinkage and dynamic draught, as well as elevations of the ship’s keel relative to chart datum, are calculated. A theoretical method using slender-body shallow-water theory is applied to calculate sinkage and trim for the transits. It is shown that the theory is able to predict ship squat (steady sinkage and trim) with reasonable accuracy for container ships at full scale in open dredged channels. In future work, the measured ship motions, along with full measured wave time series data, will be used for validating wave-induced motion software.

High-performance turf reinforcement mat (HPTRM) is a technology to strengthen the vegetation lining and enhance its anti-erosion capability. Existing studies on the erosion resistance of vegetated HPTRM systems are mainly based on large-scale tests and focus on permissible flow velocity and shear stress. In this study, a specially designed flume was used to generate high-speed open-channel flow and investigate the erosion process of a vegetated HPTRM system. In total, 48 samples of natural vegetation and three types of vegetated HPTRM systems were cultivated and tested under different slopes and discharges. Both continuous and discontinuous tests were conducted. During the tests, erosion depths, flow discharges, and flow velocities were recorded. The difference between the erosion rates of continuous and discontinuous tests indicates that the first flushing of the flow induced most of the erosion of the vegetated HPTRM system. The erosion processes of the samples displayed a decrease in erosion rate with an increase in erosion depth, which can be explained by the exposure of HPTRM and consequent increase of anti-erosion capability. The influences of flow discharge and the structure of the HPTRM on the erosion process we also investigated.

Recent extreme hydrodynamic events, such as the 2004 Indian Ocean Tsunami, 2005 Hurricane Katrina, and 2013 Typhoon Haiyan, have indicated the vulnerability of coastal communities. As a result, emphasis has been placed on understanding and developing methods of assessing the potential loads associated with these extreme events. The majority of research has focused on assessing the risk of hydrodynamic loads; however, little research has gone into assessing the potential for debris loading. The following study aimed to address the trajectory of debris within extreme hydrodynamic conditions to aid in the assessment of risk for debris loading. Laboratory experiments were performed using a dam-break wave as the hydrodynamic forcing condition. The trajectory and velocity of the debris were examined to determine the statistical characteristics of the debris motion. The study showed that the lateral displacement of the debris can be evaluated using a normal distribution, and the velocity of the debris can be conservatively modeled as the wave front velocity.