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Numerical Modelling of Oil Spill Transport in Tide-Dominated Estuaries: A Case Study of Humber Estuary, UK
No full textOil spills in estuaries are less studied and less understood than their oceanic counterparts. To address this gap, we present a detailed analysis of estuarine oil spill transport. We develop and analyse a range of simulations for the Humber Estuary, using a coupled hydrodynamic and oil spill model. The models were driven by river discharge at the river boundaries and tidal height data at the offshore boundary. Satisfactory model performance was obtained for both model calibration and validation. Some novel findings were made: (a) there is a statistically significant (p < 0.05) difference in the influence of hydrodynamic conditions (tidal range, stage and river discharge) on oil slick transport; and (b) because of seasonal variation in river discharge, winter slicks released at high water did not exhibit any upstream displacement over repeated tidal cycles, while summer slicks travelled upstream into the estuary over repeated tidal cycles. The implications of these findings for operational oil spill response are: (i) the need to take cognisance of time of oil release within a tidal cycle; and (ii) the need to understand how the interaction of river discharge and tidal range influences oil slick dynamics, as this will aid responders in assessing the likely oil trajectories
EMBREA-Web: a tool for the simulation of breach through dams and embankments
No full textThe failure of dams and embankments can have catastrophic impacts on people, properties and environment. Therefore, dam and embankment breach modelling is a fundamental stage of any flood risk assessment. EMBREA-Web has been developed to help researchers and practitioners undertake this task more easily via an online interface that is built upon the well-known simulation engine of the EMBREA breach model. EMBREA-Web is available in two versions ‘Lite’ and ‘Pro’. The Lite version is free and allows the modelling of the failure of homogeneous dams or embankments initiated by overtopping or internal erosion. The Pro version has advanced features such as modelling of non-homogeneous and layered dams and embankments and the ability to undertake Monte Carlo simulations to account for data and modelling uncertainties.
In this paper, a description of the EMBREA simulation engine is given with a detailed presentation of the ‘Lite’ and ‘Pro’ versions of EMBREA-Web. Examples of undertaking modelling runs with EMBREA-Web are also given showing how it guides and simplifies the task of undertaking breach modelling
Stable partitioned schemes for fluid-structure interaction based on consistent added mass approximation
No full textCoupling schemes for fluid structure interaction applications can be distinguished in two broad categories: monolithic schemes and partitioned schemes (explicit or implicit). In this work, we considered that the explicit partitioned schemes are the most promising coupling technique for interfacing two independent and external fluid and solid dynamics solvers. This technique has nevertheless inherent numerical stability issues, caused by the lag in the fluid and solid dynamic solutions in partitioned schemes, which leads into calculation discrepancies in the added mass force. This often leads to unconditionally unstable simulations. We propose a numerical technique that can supress instabilities by estimating and correcting the error in the added mass force calculation. The technique is applied for coupling a fluid solver based on the computational toolkit Proteus (https://proteustoolkit.org/) with the multi-physics simulation engine Chrono (https://projectchrono.org/) for solid dynamics. The approach is proven successful by performing verification and validation tests for floating structures, where it is shown that the added mass stabilisation technique is effective only in cases where the partitioned scheme is unstable. Results of an engineering application case is also shown through simulations of a floating wind platform with catenary mooring cables
DAMSAT: An Eye in the Sky for Monitoring Tailings Dams
Get PDFDuring the past decade, there have been a number of catastrophic tailings dam failures. Affordable monitoring systems, as well as methods to assess the risk posed to communities living downstream of these structures, are needed. In recent years the availability and accuracy of remote sensing information has increased, whilst its cost has decreased. This paper provides an overview of DAMSAT, a web-based system that brings together Earth observation and other data to help governments and mining companies monitor tailing dams, and estimate the downstream risks they pose. The methods developed are being piloted in Peru at a number of tailings dams, with the overall goal of improving the decision making process and sharing of information with respect to managing these structures. Engagement with Peruvian stakeholders has shown that DAMSAT provides tools that can help government authorities both reduce the risks and increase the sustainability of mining
Advanced numerical modelling of wave structure interaction
No full textThis book will serve as a reference guide, and state-of-the-art review, for the wide spectrum of numerical models and computational techniques available to solve some of the most challenging problems in coastal engineering. The topics covered in this book, are explained fundamentally from a numerical perspective and also include practical examples applications. Important classic themes such as wave generation, propagation and breaking, turbulence modelling and sediment transport are complemented by hot topics such as fluid and structure interaction or multi-body interaction to provide an integral overview on numerical techniques for coastal engineering.
Through the vision of 10 high impact authors, each an expert in one or more of the fields included in this work, the chapters offer a broad perspective providing several different approaches, which the readers can compare critically to select the most suitable for their needs. Advanced Numerical Modelling of Wave Structure Interaction will be useful for a wide audience, including PhD students, research scientists, numerical model developers and coastal engineering consultants alike
Modelling the Brumadinho tailings dam failure, the subsequent loss of life and how it could have been reduced
No full textIn recent years the number of tailings dams failures has increased. On 25 January 2019, the Brumadinho tailings dam in Brazil suddenly failed releasing a mudflow over 10 m deep comprising some 10 million m3 of mining waste which killed between 270 and 320 people. This paper details the use of an agent-based model, known as the Life Safety Model (LSM), to estimate the risk to people downstream of the Brumadinho tailings dam and to assess if the number of fatalities could have been reduced if a warning had been received prior to or at time the dam failed. The LSM modelling indicates that even if a warning had been issued as the dam failed the number of fatalities could have been reduced. Agent-based modelling tools such as the LSM can help to inform and improve emergency plans for tailings dams, which will help to reduce the risk posed by them in the future
Flood Resilience of Critical Buildings: Assessment Methods and Tools
No full textWithin the context of urban flood risk management, this chapter focuses on the vulnerability assessment and improvement of flood performance of buildings, in particular those that perform essential functions-designated as critical buildings. Three methods are presented as part of a framework for the assessment of building flood vulnerability and resilience. The first method (the "Quick Scan") is a "first pass", simple method to identify the assets most at risk of flood damage and easiest to tackle, leading to cost-effective interventions. The second method provides the necessary information and tools for selection and evaluation of flood resilient options for critical buildings while the third method (the Individual Building flood damage Tool, or IBT) allows detailed estimation of the extent of damage
A fresh look at earthquakes and reservoirs
No full textThis paper seeks to address a wide range of topics which need to be borne in mind when designing or inspecting dams in seismic areas. The content refers to reservoirs rather than dams, because there is much more to consider other than the seismic behaviour of the dams themselves
The Importance of Propagule Dispersal in Maintaining Local Populations of Rare Algae on Complex Coastlines: Padina pavonica on the South Coast of England
No full textOn dynamic coastlines, populations of protected algal species with poor dispersal might be especially vulnerable to infrequent recruitment events and local extinction. As a model, we here consider the dispersal of the alga Padina pavonica from the largest remaining and physically isolated enclaves on the south coast of England. A bio-physical model was used to investigate the likely importance of local propagule dispersal in maintaining populations. Dispersal kernels that simulate the position of propagules at different time steps over 5 days were examined from five release sites. Exceptionally steep declines in model propagule density were observed over the first few hours from release, yet over the first day, 75–85% of model propagules remained close to their source but had not reached other enclaves. After five days, the dispersal from source populations ranged from 0 to 50 km, with only ~5% remaining within the source 1 km2 area. Although distances of modelled propagule dispersal might be adequate for maintaining a regional population network, vegetative perrenation also appears to be important for persistence of P. pavonica. For rare and protected species on isolated and energetic coastlines, local conservation efforts, rather than a reliance on a wider meta-population network, remain very important to ensure long-term protection and survival