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Artykuły w czasopismach na temat "Restricted waterways"
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MANDLER, MARC B., MYRIAM W. SMITH i JAMES W. GYNTHER. "Precision Electronic Navigation in Restricted Waterways". Navigation 37, nr 4 (grudzień 1990): 319–27. http://dx.doi.org/10.1002/j.2161-4296.1990.tb01559.x.
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Hoa, Nguyen Thi Ngoc, Vu Ngoc Bich, Tran Ngoc Tu, Nguyen Manh Chien i Le Tat Hien. "Numerical Investigating the Effect of Water Depth on Ship Resistance Using RANS CFD Method". Polish Maritime Research 26, nr 3 (1.09.2019): 56–64. http://dx.doi.org/10.2478/pomr-2019-0046.
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Abstract On inland waterways the ship resistance and propulsive characteristics are strictly related to the depth of the waterway, thus it is important to have an understanding of the influence of water depth on ship hydrodynamic characteristics. Therefore, accurate predictions of hydrodynamic forces in restricted waterways are required and important. The aim of this paper is investigating the capability of the commercial unsteady Reynolds–Averaged Navier–Stokes (RANS) solver to predict the influence of water depth on ship resistance. The volume of fluid method (VOF) is applied to simulate the free surface flow around the ship. The hull resistance in shallow and deep water is compared. The obtained numerical results are validated against related experimental studies available in the literature.
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Bunyaga, Aloyce, Rene Corner-Thomas, Ina Draganova, Paul Kenyon i Lucy Burkitt. "The Behaviour of Sheep around a Natural Waterway and Impact on Water Quality during Winter in New Zealand". Animals 13, nr 9 (25.04.2023): 1461. http://dx.doi.org/10.3390/ani13091461.
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Access of livestock, such as cattle, to waterways has been shown to be a cause of poor water quality due to pugging damage and excretion entering the water. In New Zealand, regulations require that cattle, deer, and pigs are excluded from accessing waterways, but there are no such requirements for sheep. The current study utilised 24 h video cameras, global positioning system units, and triaxial accelerometers to observe the interaction of Romney ewes (n = 40) with a natural waterway. Ewes were either restricted (week 1) or given access to a reticulated water trough (week 2). Proximity data showed that ewes spent more time within 3 m of the waterway when the trough was unrestricted than when restricted (14.1 ± 5.7 and 10.8 ± 5.1 min/ewe/day, respectively; p < 0.05). Ewes travelled shorter distances on the steeper areas of paddock than flatter areas. Similarly, ewes showed a spatial preference for the flat and low sloped areas of the paddock. Concentrations of suspended sediment and total phosphorus were higher during access to a reticulated water trough which coincided with the week with more rainy days. Phosphorus and E. coli concentrations in the stream water samples were the above recommended Australian and New Zealand Environment and Conservation Council water quality guidelines, especially after rainy days, but did not appear to be directly related to sheep activity. Overall, the results suggest that during winter, ewes interacted very little with the waterway and were thus unlikely to influence the levels of nutrient and pathogens in the waterway.
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Liu, Jingxian, Feng Zhou, Zongzhi Li, Maoqing Wang i Ryan Wen Liu. "Dynamic Ship Domain Models for Capacity Analysis of Restricted Water Channels". Journal of Navigation 69, nr 3 (29.10.2015): 481–503. http://dx.doi.org/10.1017/s0373463315000764.
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Developing adequate ship domain models may significantly benefit vessel navigation safety. In essence, navigation safety is collectively affected by the navigable waterway condition, the size and shape of the ship, and operators' skills. The existing ship domains mainly use constant values for the model input parameters, making them incapable of handling site-specific conditions. This study proposes dynamic ship domain models that take into consideration navigable waterway conditions, ship behaviours, ship types and sizes, and operators' skills in a holistic manner. Specifically, the conditions of restricted waterways are classified into navigating along the channel, crossing the channel, joining another flow and turning. The ship types considered include ships that transport non-hazardous goods and Liquid Natural Gas (LNG) ships that are in need of additional security zones. A computational experiment is conducted for model application using data on water channel design and ship traffic volumes related to navigating along the channel, joining another flow and turning. Comparisons of results obtained between the proposed dynamic models with real ship traffic counts reveal that the proposed models could achieve a higher level of accuracy in estimating the capacity of restricted water channels. It therefore could potentially deliver safety enhancements of waterway transportation.
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Gucma, Lucjan, i Zbigniew Pietrzykowski. "Ship Manoeuvring in Restricted Areas: An Attempt to Quantify Dangerous Situations Using a Probabilistic-Fuzzy Method". Journal of Navigation 59, nr 2 (6.04.2006): 251–62. http://dx.doi.org/10.1017/s037346330600364x.
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This paper presents a practical application of the probabilistic-fuzzy method for assessment of the safety of a ship manoeuvring in waterways. The method, based on probabilistic risk analysis and elements of fuzzy logic, takes into account situations of threatened navigational safety and situations when a navigator intuitively thinks that the safety of manoeuvring ship is threatened. The probability of grounding a ship manoeuvring in a waterway bend is determined by means of simulation method. Then, with the use of experts' knowledge and tools of fuzzy logic the probability of a dangerous situation is determined. Two different approaches are applied for the determination of that probability. The results are compared.
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Gan, Shaojun, Yanxia Wang, Kang Li i Shan Liang. "Efficient online one-way traffic scheduling for restricted waterways". Ocean Engineering 237 (październik 2021): 109515. http://dx.doi.org/10.1016/j.oceaneng.2021.109515.
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Alderf, N., E. Lefranĉois, P. Sergent i P. Debaillon. "Transition effects on ship sinkage in highly restricted waterways". Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment 224, nr 2 (2.12.2009): 141–53. http://dx.doi.org/10.1243/14750902jeme170.
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Varyani, K. S. "Squat effects on high speed craft in restricted waterways". Ocean Engineering 33, nr 3-4 (marzec 2006): 365–81. http://dx.doi.org/10.1016/j.oceaneng.2005.04.016.
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Sergent, P., E. Lefrançois i N. Mohamad. "Virtual bottom for ships sailing in restricted waterways (unsteady squat)". Ocean Engineering 110 (grudzień 2015): 205–14. http://dx.doi.org/10.1016/j.oceaneng.2015.10.017.
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Xin, Xuri, Kezhong Liu, Jinfen Zhang, Shuzhe Chen, Hongbo Wang i Zhiyou Cheng. "A Self-Organizing Grouping Approach for Ship Traffic Scheduling in Restricted One-Way Waterway". Marine Technology Society Journal 53, nr 1 (1.01.2019): 83–96. http://dx.doi.org/10.4031/mtsj.53.1.9.
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AbstractShip scheduling optimization is one of the most effective ways to eliminate the bottlenecks of waterway transportation, especially in restricted one-way waterways. In this study, a novel scheduling model called self-organizing grouping is proposed to minimize two types of delay time, which are the waiting time and the extra navigation time caused by speed reduction. The proposed model schedules ships in an iterative way based on the distributed scheduling mode. To alleviate the impact of local scheduling on the overall traffic efficiency, a grouping method is proposed, in which the ships are divided into different groups based on their arrival time interval. Moreover, the ships in the same group are scheduled to minimize the interferences among them by incorporating a grouping improvement strategy. The strategy is used to deal with the influence of ships with very small speed. Experiments are carried out by comparing the proposed model with the first-come-first-serve model and the ship self-organizing cooperation model. Simulation results show that the delay time is reduced by 25%‐30% and approximately by 5% compared with that from the two models, respectively. Such advantage also exists for different combinations of ship traffic parameters. In addition, long-distance sailing with limited speed can be avoided using the proposed method, which is beneficial to relieve waterway traffic congestion.
Rozprawy doktorskie na temat "Restricted waterways"
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Yang, Bo. "Numerical investigation of restricted curved waterways on ship hydrodynamics for maneuverability considerations". Electronic Thesis or Diss., Compiègne, 2023. http://www.theses.fr/2023COMP2735.
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Le transport par voies navigables joue aujourd'hui un rôle important grâce aux divers avantages qu'il présente par rapport aux autres modes de transport, par exemple son faible coût, sa faible pollution environnementale et sa grande capacité, etc. Cependant, les voies navigables intérieures ne sont pas seulement naturellement courbées, mais aussi étroites et peu profondes, ce qui entraîne des environnements d'écoulement et des conditions de navigation complexes. Les bateaux de navigation intérieure sont donc susceptibles d'avoir des accidents dans les voies d'eau à courbure limitée. Ces dernières années, ce mode de transport a connu des progrès significatifs avec l'arrivée de la nouvelle génération de navires (plus grands et plus puissants), ce qui rend la manœuvrabilité des navires plus difficile dans ces eaux sensibles. Pour réaliser cette étude, le modèle CFD basé sur un solveur Navier-Stokes instationnaire dans STARCCM+ est utilisé. La vérification et la validation de ce modèle sont réalisées en respectant les recommandations du CTI. Ce dernier est ensuite utilisé pour effectuer une série de simulations en testant les paramètres clés suivants : une série de paramètres environnementaux de navigation, comprenant l'angle du chenal, la largeur du fond du chenal, l'angle de pente du chenal ; une série de paramètres liés au comportement et à la géométrie du navire, contenant le rapport entre la profondeur d'eau et le tirant d'eau, la vitesse du navire, l'angle de dérive et le type de navire (longueur du navire) sur l'hydrodynamique du navire dans les chenaux courbes restreints. Les mouvements du cadre relatif sont appliqués aux domaines de calcul pour produire la force centrifuge dans les chenaux courbés. L'objectif de la présente thèse est d'abord de caractériser les variables liées à la topologie d'un canal circulaire qui ont un impact substantiel sur la manœuvrabilité d'un navire. Deuxièmement, elle permet de bien comprendre les comportements d'écoulement qui se produisent autour d'un navire dans les zones de flexion. Troisièmement, les fluctuations de la force hydrodynamique (phénomènes de coussin de berge et de succion) et la sensibilité d'un certain nombre de variables dans les zones de flexion sont étudiées. Enfin, le simulateur de navire intérieur est amélioré en ajoutant l'effet de zone de flexion pour les pilotes, de sorte que les comportements des navires dans les régions sensibles peuvent ainsi être corrigésInland waterway transport is now playing a significant role thanks to its various advantages over the other transportation modes, for example, low cost, low environmental pollution, and large capacity, etc. However, inland waterways are not only naturally curved but also narrow and shallow, which causes complex flow environments and navigational conditions. Inland ships are consequently susceptible to accidents in restricted curved waterways. Especially during these years, this mode of transport has seen significant progress by the arrival of the new generation of ships (larger size and more powerful), and this makes ships’ maneuverability in such sensitive waters severer. To conduct this investigation, the CFD model based on an unsteady Navier-Stokes solver in STARCCM+ is used. The verification and validation of this model are realized by respecting the ITTC recommendations. The latter is then used to perform a series of simulations by testing the following key parameters: a series of navigational environmental parameters, including channel angle, channel bottom width, channel slope angle; a set of parameters related to ship behaviors and geometry, containing water depth to draft ratio, ship speed, drift angle and ship type (ship length) on ship hydrodynamics in restricted curved fairways. Relative frame motions are applied to the computational domains to produce centrifugal force in bending fairways. The aim of the present thesis is firstly to characterize the variables connected to a circular channel's topology that have a substantial impact on a ship's maneuverability. Second, it helps to well understand the flow behaviors that occur around a ship in bending zones. Thirdly, the fluctuations in hydrodynamic force (bank cushion and suction phenomena) and the sensitivity of a number of variables in bending zones are investigated. Finally, the inland ship simulator is improved by adding the bending zone effect for pilots, so that the behaviors of ships in the sensitive regions can thus be corrected
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Linde, Florian. "3D modelling of ship resistance in restricted waterways and application to an inland eco-driving prototype". Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2389/document.
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Les travaux de cette thèse ont pour but de développer un prototype d’éco-pilote, nommé EcoNav, permettant d’optimiser la vitesse d’un bateau afin de réduire sa consommation de carburant. EcoNav est composé de plusieurs modules dont : un modèle hydraulique 2D simulant l’écoulement hydrodynamique (vitesse du courant et hauteur d’eau) le long du trajet du bateau; - un modèle de résistance à l’avancement servant à alimenter un modèle de prédiction de la consommation de carburant; - un algorithme d’optimisation permettant de trouver le profil optimal de vitesse. Afin de pouvoir estimer la consommation de carburant, un modèle numérique de la résistance à l’avancement en milieu confiné a été développé durant la première partie de cette thèse. Ce modèle numérique 3D simule l’écoulement du fluide autour du bateau et permet de calculer les forces agissant sur sa coque. La résolution des équations RANS est couplée avec un algorithme de quasi-Newton afin de trouver la position d’équilibre du bateau et calculer son enfoncement. Cette méthode est validée en comparant les résultats numériques avec des résultats expérimentaux issus d’essais en bassin de traction. L’influence de l’enfoncement sur la résistance à l’avancement et la précision de la méthode est étudiée en comparant les résultats numériques obtenus avec et sans enfoncement. La précision des modèles empiriques de prédiction de la résistance à l’avancement est également comparée à celle du modèle numérique. Enfin, le modèle numérique est utilisé afin de déterminer si le confinement en largeur ou en profondeur ont une influence identique sur l’augmentation de résistance à l’avancement. Les résultats de cette étude permettent d’établir si le confinement de la voie d’eau peut être caractérisé à l’aide d’un paramètre unique (coefficient de blocage par exemple) ou bien deux paramètres permettant de distinguer le confinement latéral et vertical. Dans la seconde partie de cette thèse, les méthodes numériques utilisées pour le modèle d’éco-pilote sont décrites et comparées afin de sélectionner celles qui sont le plus adaptées à chaque module. EcoNav est ensuite utilisé afin de modéliser un cas réel : celui du bateau automoteur Oural navigant sur la Seine entre Chatou et Poses (153 km). La consommation optimisée est comparée à la consommation non optimisée, calculée à partir des vitesses AIS observées sur le tronçon étudié. L’influence de la trajectoire du bateau et de son temps de parcours sur sa consommation sont également étudiés. Les résultats de ces investigations ont montré qu’optimiser la vitesse du bateau permet d’obtenir une réduction de la consommation de carburant de l’ordre de 8 % et qu’optimiser la trajectoire du bateau ainsi que prendre en compte des informations en temps réel (disponibilité des écluses, trafic sur le fleuve) peuvent permettre de réaliser des économies de carburant supplémentairesAn eco-driving prototype, named EcoNav, is developed with the aim of optimizing a vessel speed in order to reduce fuel consumption for a given itinerary. EcoNav is organized in several modules : - a 2D hydraulic model simulating the flow conditions (current speed and water depth) along the itinerary; - a ship resistance model calculating the thrust necessary to counteract the hydrodynamic forces ; - a fuel consumption model calculating the fuel consumption corresponding to the thrust input; - a non linear optimization algorithm calculating the optimal speed profile. In order to evaluate the fuel consumption of an inland vessel, a ship resistance numerical model is developed in the first part of this PhD. This 3D numerical model simulates the flow around an inland self-propelled vessel and evaluates the hydrodynamic forces acting on the hull. A RANS solver is coupled with a quasi-Newton approach to find the equilibrium position and calculate ship sinkage. This method is validated by comparing the results of numerical simulations to towing tank tests. The numerical results with and without sinkage are also compared to study the influence of sinkage on ship resistance and on the accuracy of the method. Additionally, some empirical models are investigated and compared with the accuracy of the numerical method. Finally, the numerical model is used to determine if channel with and water depth restriction contribute to the same amount of ship resistance increase for the same level of restriction. The results of that investigation give insight to whether channel restriction can be characterized by a unique parameter (for instance the blockage ratio) or two parameters to distinguish water depth and channel with effects. In the second part of this PhD, the numerical methods used in the speed optimization model are described and validated. The speed optimization model is then used to simulate a real case: the itinerary of the self-propelled ship Oural on river Seine, between Chatou and Poses (153 km). The optimized fuel consumption is compared with the non-optimized fuel consumption, based on AIS speed profile retrieved on this itinerary. The effects of the ship trajectory and travel duration on fuel consumption are also investigated. The results of those investigations showed that optimizing the ship speed lead to an average fuel saving of 8 % and that using an optimal track and including real time information such as lock availability and river traffic can lead to additional fuel savings
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Wells, Jared Lawrence. "Effect of angular orientation on the hydrodynamic forces acting on a body in a restricted waterway". Thesis, Virginia Tech, 1985. http://hdl.handle.net/10919/41572.
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A slender body theory method developed for a body moving parallel to a wall in shallow water is extended to include angular orientation of the body to the wall. The method satisfies only the zero normal velocity condition on the external boundaries but does not take into account the effect of induced flows on the body itself. A spheroid and a Series 60, block .80 hull were the bodies studied. The side force and yaw moment on each body were determined numerically for varying angular orientation with respect to either a single wall or canal bank. For both cases results for a range of depths and wall separation distances are presented. It is found that the method gives good qualitative side force predictions for a body moving parallel to a wall, but is unable to correctly predict the yaw moment or the side force due to angular orientation. This result dictates the need for a more complex mathematical model to properly represent the flow than the simple model and quasiâ steady method used here.
Master of Science
Książki na temat "Restricted waterways"
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Associates, Eclectech, i United States. Coast Guard. Office of Research and Development., red. Short range aids to navigation systems: Design manual for restricted waterways. Washington, D.C: U.S. Coast Guard, U.S. Dept. of Transportation, Office of Research and Development, 1986.
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Smith, Andrew, Guy Osborn i Bernadette Quinn, red. Festivals and the City: The Contested Geographies of Urban Events. University of Westminster Press, 2022. http://dx.doi.org/10.16997/book64.
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This book explores how festivals and events affect urban places and public spaces, with a particular focus on their role in fostering inclusion. The ‘festivalisation’ of culture, politics and space in cities is often regarded as problematic, but this book examines the positive and negative ways that festivals affect cities by examining festive spaces as contested spaces. The book focuses on Western European cities, a particularly interesting context given the social and cultural pressures associated with high levels of in-migration and concerns over the commercialisation and privatisation of public spaces. The key themes of this book are the quest for more inclusive urban spaces and the contested geographies of festival spaces and places. Festivals are often used by municipal authorities to break down symbolic barriers that restrict who uses public spaces and what those spaces are used for. However, the rise of commercial festivals and ticketed events means that they are also responsible for imposing physical and financial obstacles that reduce the accessibility of city parks, streets and squares. Alongside addressing the contested effects of urban festivals on the character and inclusivity of public spaces, the book addresses more general themes including the role of festivals in culture-led regeneration. Several chapters analyse festivals and events as economic development tools, and the book also covers contested representations of festival cities and the ways related images and stories are used in place marketing. A range of cases from Western Europe are used to explore these issues, including chapters on some of the world’s most significant and contested festival cities: Venice, Edinburgh, London and Barcelona. The book covers a wide range of festivals, including those dedicated to music and the arts, but also events celebrating particular histories, identities and pastimes. A series of fascinating cases are discussed - from the Venice Biennale and Dublin Festival of History, to Rotterdam’s music festivals and craft beer festivals in Manchester. The diverse and innovative qualities of the book are also evident in the range of urban spaces covered: obvious examples of public spaces – such as parks, streets, squares and piazzas – are addressed, but the book includes chapters on enclosed public spaces (e.g., libraries) and urban blue spaces (waterways) too. This reflects the interpretation of public spaces as socio-material entities: they are produced informally through their use (including for festivals and events), as well as through their formal design and management.
Części książek na temat "Restricted waterways"
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Ouahsine, Abdellatif, Ji Shengcheng, Hassan Smaoui, Philippe Sergent i Nicolas Huybrechts. "3D Numerical Simulation of Convoy-generated Waves and Sediment Transport in Restricted Waterways". W Materials and Infrastructures 2, 147–58. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119318613.ch11.
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Wan, Zhiyong, Yun Li, Jianfeng An, Xiaogang Wang i Xiujun Yan. "Analysis of Water Level Fluctuations in Bifurcating Approach Channels Under the Flow Regulation of Reservoirs". W Lecture Notes in Civil Engineering, 1447–59. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-6138-0_128.
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AbstractAn approach channel is a restricted channel connecting the lock head with the upstream and downstream navigation waterway, characterized by a narrow navigation channel with a closed-end, small coefficient of cross-section, and low speed for vessel navigating. Due to the uncertain impact of the waves induced by the flow regulation of reservoirs on water-level fluctuations in bifurcating approach channels, the river reach between the Three Gorges Dam (TGD) and the Gezhouba Dam (GZD) is selected as the study area and the variations of water-level fluctuating amplitude in the approach channel located on the left bank downstream of the TGD are revealed under the joint regulation of the Three Gorges and Gezhouba reservoirs based on numerical simulations. Furthermore, the relationship between water level variation at the lower lock head of the ship lift and the flow regulation of reservoirs is investigated in detail. Results indicated that water level variation of the ship lift approach channel exhibits an amplifying effect and the lower lock head of the ship lift is a key concern for navigable flow conditions. In addition, the flow variation rate should be controlled within the range of 2,000 m3/15 min in the context of joint regulation of two reservoirs, which enables the safe docking of vessels at the lower lock head of the ship lift. The findings in this study may contribute to the designing and planning of the newly-planned Three Gorges ship lock approach.
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Erbig, Jeffrey Alan. "An Archipelago of Settlements and Tolderías". W Where Caciques and Mapmakers Met, 12–38. University of North Carolina Press, 2020. http://dx.doi.org/10.5149/northcarolina/9781469655048.003.0002.
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This chapter examines the imperial and Indigenous territorialities that defined the Río de la Plata before the invention of a Luso-Hispanic border. It demonstrates that itinerant Native communities (tolderías) were the principal arbiters of access to and travel across the countryside, where feral livestock roamed. Strings of Spanish, Portuguese, and Jesuit-Guarani settlements, rather than constituting conterminous frontiers or provincial units, were relatively isolated points along fragile corridors or waterways, restricted to the perimeter of the region by neighboring tolderías. Tolderías competed with one another and used colonial settlements for trade or as sites of temporary refuge in moments of duress. In the absence of any singular authority, territorial order governed power relations between settlers and tolderías, and tilted in tolderías’ favor.
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"Determination of safe maneuvering areas of towed sea barges carrying offshore wind farm elements in restricted waterways". W Towards Green Marine Technology and Transport, 469–74. CRC Press, 2015. http://dx.doi.org/10.1201/b18855-61.
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Draganov, Deyan, Xu Ma, Menno Buisman, Tjeerd Kiers, Karel Heller i Alex Kirichek. "Non-Intrusive Characterization and Monitoring of Fluid Mud: Laboratory Experiments with Seismic Techniques, Distributed Acoustic Sensing (DAS), and Distributed Temperature Sensing (DTS)". W Sediment Transport - Recent Advances [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.98420.
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In ports and waterways, the bathymetry is regularly surveyed for updating navigation charts ensuring safe transport. In port areas with fluid-mud layers, most traditional surveying techniques are accurate but are intrusive and provide one-dimensional measurements limiting their application. Current non-intrusive surveying techniques are less accurate in detecting and monitoring muddy consolidated or sandy bed below fluid-mud layers. Furthermore, their application is restricted by surveying-vessels availability limiting temporary storm- or dredging-related bathymetrical changes capture. In this chapter, we first review existing non-intrusive techniques, with emphasis on sound techniques. Then, we give a short review of several seismic-exploration techniques applicable to non-intrusive fluid-mud characterization and monitoring with high spatial and temporal resolution. Based on the latter, we present recent advances in non-intrusive fluid-mud monitoring using ultrasonic transmission and reflection measurements. We show laboratory results for monitoring velocity changes of longitudinal and transverse waves propagating through fluid mud while it is consolidating. We correlate the velocity changes with shear-strength changes while the fluid mud is consolidating and show a positive correlation with the yield stress. We show ultrasonic laboratory results using reflection and transmission techniques for estimating the fluid-mud longitudinal- and transverse-wave velocities. For water/mud interface detection, we also use distributed acoustic sensing (DAS) and distributed temperature sensing (DTS).
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"Paddlefish Management, Propagation, and Conservation in the 21st Century". W Paddlefish Management, Propagation, and Conservation in the 21st Century, redaktorzy DANIEL M. O’KEEFE i DONALD C. JACKSON. American Fisheries Society, 2009. http://dx.doi.org/10.47886/9781934874127.ch6.
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<em>Abstract</em>.—Paddlefish <em>Polyodon spathula </em>vanished from areas of the upper Tombigbee River basin in Mississippi and Alabama during the 1950s, long before channelization and damming associated with construction of the Tennessee-Tombigbee Waterway (TTW) were completed in 1984. This study was undertaken to assess distribution and population dynamics of any remaining stock. Paddlefish were not captured in upstream impoundments, but an unexploited remnant population was located in the downstream impoundment: Demopolis Lake, Alabama. Paddlefish in Demopolis Lake were characterized by a population density of 2.6 fish/ha, high growth rate relative to more northern populations, and natural annual mortality rate (<em>A </em>= 0.406) similar to other southern populations. Two wintering habitats (cutoff bendways) were heavily utilized by paddlefish. Large males primarily inhabited the more lotic bendway while females and small males were more common in the more lentic bendway, indicating differential importance of habitats among demographic groups. The restricted distribution of TTW paddlefish and demographic differences between habitats suggest that areas heavily utilized by paddlefish should be protected from further degradation. Sedimentation has resulted in reductions of bendway depth and reduced connectivity of backwaters, reducing availability of suitable paddlefish habitat. Restoring connectivity of bendways through dredging could reverse this trend and provide other benefits to fisheries.
Streszczenia konferencji na temat "Restricted waterways"
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Daggett, L. L. "Modeling Realistic Ship Behavior in Highly Restricted Waterways". W SNAME 23rd American Towing Tank Conference. SNAME, 1992. http://dx.doi.org/10.5957/attc-1992-003.
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Recent simulation testing of existing and proposed improvements to the Houston Ship Channel (HSC) in Galveston Bay has demonstrated the need for additional information on the behavior of ship maneuvering and passing in very restricted waterways. Modeling based on towing tank tests for bank/ship and ship/ship interactions had to be seriously modified for the ships to respond as the pilots indicate ships behave in the HSC. Comparison with scale physical models indicates that these modifications do produce ship motions similar to those measured with the free-running physical models. Prototype measurements also indicate the behavior is being reproduced with the revised simulator model. This suggests the need for new and better methods for determining ship behavior in highly restricted waterways that can account for the free motion of the ship.
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Zhou, Xueqian, Ping Xin, Dezheng Jia, Jin Huang i Donghao Xu. "Ship Path Following Control via Output Redefinition Method in Restricted Waters". W ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/omae2022-81422.
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Abstract Due to the advances in shipbuilding technology and the needs in the shipping industry, the ship dimensions have kept increasing, and so is the traffic in the ports, approach channels, and harbors. Increase in ship dimensions and traffic in restricted waterways results in challenges in waterway transportation safety. Safe maneuver of ships of overtaking and encounter is one of them. This paper addresses the problem of the path control of ships in parallel motion in restricted waters accounting for the hydrodynamic effects, in which, the path control with nonminimum phase zero dynamics is a major concern. A new output redefinition method has been developed to solve the nonminimum phase zero dynamics. With the assumption of low-frequency ship motion in restricted waters and the use of the output redefinition method, a new ship response equation is proposed. Based on the new ship response equation, a feedforward + PID control law has been developed to control ship parallel motion in restricted waters. Simulation results show good control effect in medium hydrodynamic interaction, the control law and ship response equation can enhance the safety of ships moving in restricted waters.
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Renilson, M., i S. Lenz. "An Investigation into Effect of Hull Form on the Wake Wave Generated by Low Speed Vessels". W SNAME 22nd American Towing Tank Conference. SNAME, 1989. http://dx.doi.org/10.5957/attc-1989-049.
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The erosion caused by vessel wake has for many years caused problems in restricted waterways (See for example Camfield et al. [1980]). It has generally been assumed that the errosive qualities of a wake wave pattern is related to the maximum wave height of that pattern. (Nanson et al, [1987]). In order to investigate the effect of hull shape on the size of the wave, model and full scale experiments were carried out by the Ship Hydrodynamics Centre at the Australian Maritime College.
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Lou, Peng-yu, i Zao-Jian Zou. "Numerical Calculation of the Viscous Hydrodynamic Forces on a KVLCC Hull Sailing Along Channel Bank". W ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-83681.
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In restricted waters, ships often need to navigate along banks of the waterways. In such case, the hydrodynamic lateral force and yaw moment acting on the ships will be induced due to the asymmetric flow about the ship hull. Accurately predicting these force and moment is of practical significance to ensure a safe navigation and can provide some guidance on correct manoeuvring and control of ships in restricted waters. In the present paper, to study the bank effects on the hydrodynamic forces acting on a ship manoeuvring in restricted waters, the viscous flow around an unappended ship sailing in a straight course along the channel bank and simultaneously undergoing sway motion is numerically simulated by using a CFD-based viscous flow solver. The steady and unsteady RANS equations in conjunction with a RNG k-ε turbulence model are solved by using the dynamic mesh technique and UDF (User-Defined Function). Numerical study is conducted for a KVLCC model. The hydrodynamic lateral force and yaw moment acting on the hull are calculated at different ship-to-bank distance and different water depth. By comparing the numerical results, the effects of ship-to-bank distance on the hydrodynamic forces are analyzed.
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Babu, Mannam Naga Praveen, i P. Krishnankutty. "Numerical Study on Fish Tail Shaped Rudder for Improved Ship Maneuvering". W ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/omae2015-41613.
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Maneuvering is an important safety aspect in ship operations so as to avoid accident of ships in seaways and more critically in the restricted area of waterways. IMO stipulates many safety regulations on ship maneuverability in open sea conditions and the local authorities may have additional regulations in harbor, canal and other restricted waterways. The effectiveness of rudder has substantial influence on the maneuverability of a ship. It is often difficult to increase the size of the rudder, to get higher control force/moment, due to the geometrical restrictions of the aft aperture of the ship. A hydrodynamically efficient rudder section addresses this problem to some extent. Most of the fishes maneuver efficiently using their tail. The fish tail functions almost similar to that of a rudder for its movements and navigation. In general, ship with flap rudders and fish tail shaped rudders perform maneuverability better compare to a ship fitted with a conventional rudder having the same underwater surface area. In fishtail shaped rudders, the shape and movements promote good flow patterns in a wider range of rudder angles. In a fish tail, the trailing edge accelerates the flow and recovers lift over the aft section of the rudder. This results in the generation of a higher lift and thus helps in reducing the turning diameter of the vessel. The studies carried out with two rudder types — conventional rudder and fish tail shaped rudder — are presented in this paper. Numerical simulations are performed on these two rudders, both having the same surface area, for different rudder angles in free stream condition. The lift force generated by the fish tail shaped rudder is found to be higher than the conventional rudder. The flow across and the hydrodynamic forces acting on the sections are determined using a commercial CFD code. The effectiveness of the fishtail rudder is also brought out from the numerically simulated turning maneuver of a chosen ship fitted with the same rudder.
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Abreu, Danilo T. M. P., Marcos C. Maturana, Marcelo R. Martins i Siegberto R. Schenk. "Human Reliability Analysis of Ship Maneuvers in Harbor Areas". W ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/omae2019-96251.
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Abstract During a ship life cycle, one of the most critical phases in terms of safety refers to harbor maneuvers, which take place in restricted and congested waters, leading to higher collision and grounding risks in comparison to open sea navigation. In this scenario, a single accident may stop the harbor’s traffic as well as incur into patrimonial damage, environmental pollution, human casualties and reputation losses. In order to support the vessel’s captain during the maneuver, local experienced maritime pilots stay on board coordinating the ship navigation while in restricted waters. Because of their shorter relative duration, harbor maneuvers accidents are more probable to occur due to human errors — reinforced by the inherent surrounding difficulties —, rather than machinery failures, for instance. The human errors are object of study of the human reliability analysis (HRA). Aiming to assess the main factors contributing to human errors in pilot-assisted harbor ship maneuvers, this work proposes a Bayesian network model for HRA, supported by a prospective human performance model for quantification. Similar works focus mainly on open sea navigation and collision accidents, which do not reflect the strict conditions found on port areas. Additionally, most of the models are highly dependent on expert’s opinion for quantification. Therefore, the novelty of this work resides into two aspects: a) incorporation of harbor specific conditions for maritime navigation HRA, including the performance of ship’s crew and maritime pilots; and b) the use of a prospective human performance model as an alternative to expert’s opinion for quantification purposes. To illustrate the usage of the proposed methodology, this paper presents an analysis of the route keeping task along waterways, starting from the quantification of human error probabilities (HEP) and including the ranking of the main external factors that contribute to the HEP.
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Lataire, Evert, Marc Vantorre i Guillaume Delefortrie. "The Influence of the Ship’s Speed and Distance to an Arbitrarily Shaped Bank on Bank Effects". W ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/omae2015-41835.
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A displacement vessel — obviously — displaces a (large) amount of water. In open and deep navigation areas this water can travel almost without any restriction underneath and along the ship’s hull. In restricted and shallow waterways, however, the displaced water is squeezed under and along the hull. These bathymetric restrictions result in increased velocities of the return flow along the hull. The resulting pressure distribution on the hull causes a combination of forces and moments on the vessel. If generated because of asymmetric flow due to the presence of a bank, this combination of forces and moment is known as bank effects. By far the most comprehensive and systematic experimental research program on bank effects has been carried out in the Towing Tank for Manoeuvres in Shallow Water (cooperation Flanders Hydraulics Research – Ghent University) at Flanders Hydraulics Research (FHR) in Antwerp, Belgium. The obtained data set on bank effects consists of more than 14 000 unique model test setups. Different ship models have been tested in a broad range of draft to water depth ratios, forward speeds and propeller actions. The tests were carried out along several bank geometries at different lateral positions between the ship and the installed bank. The output consists of forces and moments on hull, rudder and propeller as well as vertical ship motions. An analysis of this extensive database has led to an increased insight into the parameters which are relevant for bank effects. Two important parameters are linked to the relative distance between ship and bank and the ship’s forward speed. The relative position and distance between a ship and an arbitrarily shaped bank is ambiguous. Therefore a definition for a dimensionless distance to the bank will be introduced. In this way the properties of a random cross section are taken into account without exaggerating the bathymetry at a distance far away from the ship or without underestimating the bank shape at close proximity to the ship. The dimensionless velocity, named the Tuck number (Tu), considers the water depth and blockage, and is based on the velocity relative to the critical speed. The latter is dependent on the cross section (and thus the bank geometry) of the waterway.
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Ankudinov, Vladimir, Bent Jakobsen i Larry Oaggett. "Maneuvering Performance of the Push Tows Based on the Analysis of Model Tests and Identification Techniques with the Full-Scale Trial Data". W SNAME 22nd American Towing Tank Conference. SNAME, 1989. http://dx.doi.org/10.5957/attc-1989-056.
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The capability to describe the dyna mic waterway environment and corresponding vessel response using time-domain simulation models has increased significantly in recent years. Provided that comprehensive data on the navigation channel, and sophisticated mathematical models are available, numerical investigations of various navigational problems in waterways and the impact of channel/vessel modifications can be carried out effectively and at low coat. However, such investigations require an adequate modeling capability verified with full scale trial data. There are basically three alternatives available to evaluate the hydrodynamic forces acting on the vessel: (1) Directly from model testing including measurements of the resistance/propulsion hydrodynamic forces and ship maneuvering forces (coefficients) acting on the vessel in a maneuver. Any model test results suffer from “scale effects”, primarily of the viscous nature because modeling of the viscous phenomenon cannot be accomplished in typical model tests. Scale effects can be minimized by conducting model tests with large models and recalculation of the viscous forces for the prototype vessel. This is a critical item in ship maneuvering performance assessments because the governing hydrodynamic forces acting on a maneuvering ship are of viscous nature. (2) Indirectly from various semi-empirical approaches typically synthesizing experimental, statistical and analytical methods for a range of ship hull configurations and ship operational conditions. For certain ship types such as tankers or full-sized cargo vessels which have been extensively tested in the past, accuracy of the predictions are comparable to the accuracy of the model test results. In regard to push-tow operations only very limited Information is available. (3) Indirectly, from full-scale trials (of ten expensive) by applying various techniques for system identification to evaluate resistance/propulsion and maneuvering forces at full scale Reynolds number. The process of statistical system identification (SI) developed for specific engineering applications typically involves inputting a disturbance to the system, and matching output to input in order to identify the makeup of the system. In the case of vessel motions this corresponds to calling for specific rudder/propeller commands, measuring the vessel response and identifying the hydrodynamic coefficients in surge-sway-yaw maneuvering equations using primarily probabilistic estimation methods. The success of the identification, depends heavily on the quality of the measurements (and therefore , instrumentation, its accuracy, weather, and fairing process techniques utilized) and on the number of the unknown parameters to be determined. The river tows are extensively used in inland waterway systems and consist of a push towboat and some mix of the standard river barges. The hydrodynamics of the typical river tow flotilla is complex and reliable test data are rare. In recent years the Army Corps of Engineers and U.S.C.G. has sponsored several fundamental studies carried out by Tracor Hydronautics, Inc. (THI) In support of an integrated approach in ship-channel design and navigation problems, see References 1 to 4. The principal goal of these studies has been experimental/analytical prediction data base for an assessment of maneuvering performance of a typical river tow flotilla in a restricted waterway channel. The investigation (1) included extensive model tests of a 15-barge tow in both deep and shallow waters, development of a method for predicting tow hydrodynamic coefficients, simulations of tow behavior as a function of channel dimensions, and effects of channel alterations on navigation performance. Model test results, analyses, and maneuvering predictions for 6 and 25 barge river tows are given in References 2 and 3. Identification of the hydrodynamic coefficients of the 15 barge tow based on the recently developed identification techniques and full-scale trials of tows on Lake Pontchartrain in New Orleans, are presented in Reference 4. To compliment recently conducted model testing of a 6 barge tow, THI has also identified the maneuvering coefficients of a three long by two wide barge assembly from the 1985 trial data, Reference 4. The principal results of these studies are presented in this paper.
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Liu, Han, Ning Ma i Xiechong Gu. "Numerical Prediction of Ship Hydrodynamic Derivatives in Close Proximity to a Vertical Bank and Maneuvering Stability Analysis". W ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/omae2016-54528.
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As bank effect has a remarkable influence on the maneuverability of a ship proceeding close to a vertical bank, the assessment of ship maneuvering stability is of great importance. The hydrodynamic derivatives of a ship can reflect the change of the ship’s maneuverability and they are determined with the method of planar motion mechanism (PMM) tests. This paper presents a numerical way to simulate the PMM captive model tests for the ship KVLCC2. A general purpose viscous flow solver was adopted to solve unsteady Reynolds averaged Navier Stokes (RANS) equations in conjunction with a RNG k-ε turbulence model. A hybrid dynamic mesh technique is developed to update the mesh volume around the ship hull when the ship is undertaking pure yaw motions and it turns out efficient and effective to solve the limitation of small ship-bank distance to the mesh configuration and remeshing.. The numerical simulations and the accuracy of the numerical method was validated in comparison with the results of PMM tests in a circulating water channel. Then a series of distances between ship and bank together with different water depths were set for simulating the PMM tests of the KVLCC2 model in proximity to a vertical bank. The first order hydrodynamic derivatives of the ship were analyzed from the time history of lateral force and yaw moment according to the multiple-run simulating procedure. The values of derivatives in different lateral proximities to the bank and variant water depths were compared and it showed some favorable trends for predicting the ship’s maneuverability in the restricted waterways. For example, the influence of velocity derivatives on lateral force reduces while that of velocity derivatives on yaw moment strengthens and this is partly due to the suction force and bow-out moment caused by bank wall effect. The straight line stability and directional stability in terms of the calculated hydrodynamic derivatives were also discussed based on the MMG model for ship maneuvering. Results indicate that the ship is inherently unstable without control and the enhancement of bank effect makes the condition even worse. Moreover, a stable or unstable zone of PD controller parameters focusing on the directional stability was illustrated and setting the values of controller parameters in the range of “Control with high sensitivity” is recommended for cases of the ship navigating in very close proximity to a bank.
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Abreu, Danilo Taverna Martins Pereira de, Marcos Coelho Maturana i Marcelo Ramos Martins. "Development of Accidental Scenarios Involving Human Errors for Risk Assessment in Restricted Waters". W ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18996.
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Abstract The navigation in restricted waters imposes several challenges when compared to open sea navigation. Smaller dimensions, higher traffic density and the dynamics of obstacles such as sandbanks are examples of contributors to the difficulty. Due to these aspects, local experienced maritime pilots go onboard in order to support the ship’s crew with their skills and specific regional knowledge. Despite these efforts, several accidents still occur around the world. In order to contribute to a better understanding of the events composing accidental sequences, this paper presents a hybrid modelling specific for restricted waters. The main techniques used are the fault tree analysis and event tree analysis. The former provides a framework to investigate the causes, while the latter allows modelling the sequence of actions necessary to avoid an accident. The models are quantified using statistical data available in the literature and a prospective human performance model developed by the Technique for Early Consideration of Human Reliability (TECHR). The results include combined estimates of human error probabilities and technical failure probabilities, which can be used to inform the causation factor for a waterway risk analysis model. In other words, given that the ship encounters a potential accidental scenario while navigating, the proposed models allow computing the failure probability that of the evasive actions sequence. The novelty of this work resides on the possibility of explicitly considering dynamicity and recovery actions when computing the causation factor, what is not a typical feature of similar works. The results obtained were compared with several results available in the literature and have been shown to be compatible.
Raporty organizacyjne na temat "Restricted waterways"
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Chapman, Ray, Phu Luong, Sung-Chan Kim i Earl Hayter. Development of three-dimensional wetting and drying algorithm for the Geophysical Scale Transport Multi-Block Hydrodynamic Sediment and Water Quality Transport Modeling System (GSMB). Engineer Research and Development Center (U.S.), lipiec 2021. http://dx.doi.org/10.21079/11681/41085.
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The Environmental Laboratory (EL) and the Coastal and Hydraulics Laboratory (CHL) have jointly completed a number of large-scale hydrodynamic, sediment and water quality transport studies. EL and CHL have successfully executed these studies utilizing the Geophysical Scale Transport Modeling System (GSMB). The model framework of GSMB is composed of multiple process models as shown in Figure 1. Figure 1 shows that the United States Army Corps of Engineers (USACE) accepted wave, hydrodynamic, sediment and water quality transport models are directly and indirectly linked within the GSMB framework. The components of GSMB are the two-dimensional (2D) deep-water wave action model (WAM) (Komen et al. 1994, Jensen et al. 2012), data from meteorological model (MET) (e.g., Saha et al. 2010 - http://journals.ametsoc.org/doi/pdf/10.1175/2010BAMS3001.1), shallow water wave models (STWAVE) (Smith et al. 1999), Coastal Modeling System wave (CMS-WAVE) (Lin et al. 2008), the large-scale, unstructured two-dimensional Advanced Circulation (2D ADCIRC) hydrodynamic model (http://www.adcirc.org), and the regional scale models, Curvilinear Hydrodynamics in three dimensions-Multi-Block (CH3D-MB) (Luong and Chapman 2009), which is the multi-block (MB) version of Curvilinear Hydrodynamics in three-dimensions-Waterways Experiments Station (CH3D-WES) (Chapman et al. 1996, Chapman et al. 2009), MB CH3D-SEDZLJ sediment transport model (Hayter et al. 2012), and CE-QUAL Management - ICM water quality model (Bunch et al. 2003, Cerco and Cole 1994). Task 1 of the DOER project, “Modeling Transport in Wetting/Drying and Vegetated Regions,” is to implement and test three-dimensional (3D) wetting and drying (W/D) within GSMB. This technical note describes the methods and results of Task 1. The original W/D routines were restricted to a single vertical layer or depth-averaged simulations. In order to retain the required 3D or multi-layer capability of MB-CH3D, a multi-block version with variable block layers was developed (Chapman and Luong 2009). This approach requires a combination of grid decomposition, MB, and Message Passing Interface (MPI) communication (Snir et al. 1998). The MB single layer W/D has demonstrated itself as an effective tool in hyper-tide environments, such as Cook Inlet, Alaska (Hayter et al. 2012). The code modifications, implementation, and testing of a fully 3D W/D are described in the following sections of this technical note.