An improved model for fast and reliable harbour wave agitation assessment

ABSTRACT: This study presents the new advances achieved in the field of harbour agitation climate assessment. Based on the improvement of an elliptic mild-slope model (MSP), which realistically reconstructs waves inside any-sized basin, represented by high-detailed unstructured meshes, and forced by real-shaped outer spectral data. A new solver is proposed for high performance runs, which allow fast agitation hindcast for statistical downtime analysis within an iterative and multi-scenario approach. Also, a realistic assimilation of partial reflection processes in quays/docks/wharfs/breakwaters is proposed. The model has been successfully validated in several harbours of special relevance in Spain with in situ measurements, through the assimilation of the hybrid downscaling (Camus et al., 2011) technique combined with monochromatic-based wave spectral reconstruction.This work has been also partially funded under the RETOS program of the Spanish Ministry of Science, Innovation and Universities (BIA2017-87213-R). We would like to thank Puertos del Estado of Spain for providing spectral outer wave spectral forcing and wave agitation measurements, for gather/organize each Port Authority base data required

Mimetic Coastal Ocean Modeling In General Coordinates And Using Machine Learning Based Predictions

Nonlinear internal waves are a ubiquitous and fundamental aspect of the coastal ecosystem understanding. However, they rely on extreme geographical conditions and precise dimensional equilibrium to be captured accurately. The General Curvilinear Coastal Ocean Model (GCCOM) was validated, serial and parallel versions for a set of experiments showcasing stratified and non-hydrostatic flow phenomena. Still, the 3D curvilinear capability has proven to be elusive. We apply cutting-edge numerical methods to improve upon the previously validated GCCOM, elevating it to field-scale capacity. This reformulation of the GCCOM equations uses novel 3D curvilinear mimetic operators, a buoyancy body force, and mimetic upwind and gradient-based momentum equations developed for this work. This model represents the most complete implementation of the 3D curvilinear mimetic operators utilizing the MOLE library or any other mimetic applications in literature to date. Results show it to be more physically accurate and better energy conserving than the validated GCCOM and other similar models, permitting the use of 3D curvilinear grids for arbitrary geometries, parallelizable arbitrary domain decomposition, and order-of-magnitude wider time steps. Additionally, we implement machine learning models to coastal ocean data to predict Dissolved Oxygen (DO) content with supervised methods; results show a Median Absolute Percentage Error (MAPE) of 2-6% for instantaneous indirect readings of DO and 0.18% for five days forecast of DO in coastal areas, using a previously predicted temperature of 1.60% MAPE. Dissolved Oxygen is known to be a critically important component to track in coastal environments but also expensive to measure and almost impossible to model with traditional methods due to high nonlinearity. The ML component of this thesis opens the possibility of high precision indirect estimates of biogeochemical quantities, along with highly accurate time series forecasts and a host of new applications of machine learning to environmental sciences

Numerical Modeling of Flexible Structures in Open Ocean Environment

The dissertation presents advancements in numerical modeling of offshore aquaculture and harbor protection structures in the open ocean environment. The advancements were implemented in the finite element software Hydro-FE that expands the Morison equation approach previously incorporated in Aqua-FE software developed at the University of New Hampshire. The concept of equivalent dropper was introduced and validated on the example of a typical mussel longline design. Parametric studies for mussel dropper drag coefficients and bending stiffness contributions were performed for different environmental conditions. To model kelp aggregates in macroalgae aquaculture, a corresponding numerical technique was developed. The technique proposes a modified Morison-type approach calibrated in full-scale physical tow tank experiments conducted at Hydromechanics Laboratory of the United States Naval Academy. In addition to the numerical modeling techniques, an advanced methodology for multidimensional approximation of the current velocity fields around offshore installations was proposed. The methodology was applied to model a response of a kelp farm by utilizing tidal-driven acoustic Doppler current profiler measurements. Finally, a numerical model of a floating protective barrier was built in the Hydro-FE software to evaluate its seaworthiness. The model was validated by comparison to measurements obtained in scaled physical wave tank tests and field deployments

Remote Sensing

This dual conception of remote sensing brought us to the idea of preparing two different books; in addition to the first book which displays recent advances in remote sensing applications, this book is devoted to new techniques for data processing, sensors and platforms. We do not intend this book to cover all aspects of remote sensing techniques and platforms, since it would be an impossible task for a single volume. Instead, we have collected a number of high-quality, original and representative contributions in those areas

Structure-Seabed Interactions in Marine Environments

The phenomenon of soil–structure interactions in marine environments has attracted great attention from coastal geotechnical engineers in recent years. One of the reasons for the growing interest is the rapid development of marine resources (such as in the oil and gas industry, marine renewable energy, and fish farming industry) as well as the damage to marine infrastructure that has occurred in the last two decades. To assist practical engineers in the design and planning of coastal geotechnical projects, a better understanding of the mechanisms of soil–structure interactions in marine environments is desired. This Special Issue reports the recent advances in the problems of structure–seabed interactions in marine environment and provides practical engineers and researchers with information on recent developments in this field

Non-intrusive reduced order models and their applications

Reduced order models (ROMs) have become prevalent in many fields of physics as they offer the potential to simulate dynamical systems with substantially increased computation efficiency in comparison to standard techniques. Among the model reduction techniques, the proper orthogonal decomposition (POD) method has proven to be an efficient means of deriving a reduced basis for high-dimensional flow systems. The intrusive ROM (IROM) is normally derived by the POD and Galerkin projection methods. The IROM is appealing for non-linear and linear model reductions and has been successfully applied to numerous research fields. However, IROMs suffer from instability and non-linearity efficiency issues. In addition, they can be complex to code because they are intrusive. In most cases the source code describing the physical system has to be modified in order to generate the reduced order model. These modifications can be complex, especially in legacy codes, or may not be possible if the source code is not available (e.g. in some commercial software). To circumvent these shortcomings, non-intrusive approaches have been introduced into ROMs. The Non-Intrusive ROM (NIROM) is independent of the original physical system. The key contribution of this thesis are: Firstly, three novel NIROMs have been presented in this thesis: POD/Taylor series, POD-Smolyak and POD-RBF (radial basis function). Secondly, two NIROMs with varying material properties have been presented. Thirdly, these newly developed NIROMs were implemented and tested under the framework of an unstructured mesh finite element model (FLUIDITY) and a combined finite-discrete element method based solid model (Y2D). Fourthly, these NIROMs have been used to construct ROMs for multi-scale 3-D free surface flows, multi-phase porous media flows, fluid-structure interaction and blasting problems.Open Acces

Development of a methodology to obtain climate change projections of coastline evolution considering multiple time and spatial scales in an uncertainty context

RESUMEN: En esta tesis doctoral se establece un marco para el análisis de impactos costeros compatible con los condicionantes computacionales y de escala impuestos por el cambio climático y orientado hacia una mejor estimación del riesgo y hacia el diseño de estrategias de adaptación efectivas. Para ello, se desarrolla un modelo de evolución de la línea de costa basado en la física de los procesos y enriquecido por datos mediante asimilación. Una vez validado, el modelo se usa para pronosticar la respuesta de un tramo costero considerando la incertidumbre asociada al oleaje y al nivel del mar futuros. Esas proyecciones de la línea de costa se emplean a su vez para actualizar la morfología costera y obtener proyecciones de inundación que incorporan el efecto de la erosión. Finalmente, se desarrolla un nuevo modelo capaz de resolver de forma acoplada la evolución de la línea de costa y la morfología costera aplicable a diferentes configuraciones incluidas playas con corales, vegetación y estructuras antrópicas.ABSTRACT: In this PhD thesis, a coastal impact modelling framework that fulfills the computational and scale constraints imposed by climate change and oriented to produce better risk estimates and designing effective adaptation strategies, is established. To this end, a novel physics-based and data-assimilated shoreline evolution model is built. Once validated, the model is used to forecast the shoreline response considering climate-related uncertainty associated to future waves and water levels. Next, the shoreline projections are employed to update the nearshore morphology and to obtain erosion-enhanced flooding projections. Finally, a novel model capable of jointly resolving the shoreline evolution and the complete coastal morphology applicable to most of the sandy coastal settings worldwide including beaches protected by coral reefs, vegetation or man-made structures; is developed

Proceedings of the XIXth TELEMAC-MASCARET User Conference 2012, 18 to 19 October 2012, St Hugh's College, Oxford

Water Qualit