Operational tsunami modelling with TsunAWI – recent developments and applications

In this article, the tsunami model TsunAWI (Alfred Wegener Institute) and its application for hindcasts, inundation studies, and the operation of the tsunami scenario repository for the Indonesian tsunami early warning system are presented. TsunAWI was developed in the framework of the German-Indonesian Tsunami Early Warning System (GITEWS) and simulates all stages of a tsunami from the origin and the propagation in the ocean to the arrival at the coast and the inundation on land. It solves the non-linear shallow water equations on an unstructured finite element grid that allows to change the resolution seamlessly between a coarse grid in the deep ocean and a fine representation of coastal structures. During the GITEWS project and the following maintenance phase, TsunAWI and a framework of pre- and postprocessing routines was developed step by step to provide fast computation of enhanced model physics and to deliver high quality results

Numerical simulation of oil spills in coastal areas using shallow water equations in generalised coordinates

The pollution generated by accidental marine oil spills can cause persistent ecological disasters and lead to serious social and economical damages. Numerical simulations are a valuable tool to make proper decisions in emergency situation or to plan response actions beforehand. The main objective of this work was to improve SIMOIL, a computational model developed earlier at URV and capable of predicting the evaporation and spreading of massive oil spills in coastal areas. Specifically, a new coastal current model, based on the resolution of the shallow water equations in generalised coordinates, has been developed and validated and then coupled to SIMOIL. The model was specially designed to describe coastal oceanic flows over topography accounting for Coriolis force, eddy viscosity, seabed friction and to couple with SIMOIL in domain with complex boundaries. The equations have been discretized over generalised domains by means of finite differences of second order accuracy. The code was then implemented in FORTRAN. The code has been validated extensively against numerical and experimental flow studies of the bibliography. Finally, the new complete version of SIMOIL, coupling the shallow water model and the oil slick model, has been applied to the study of two accidental oil spills: • A massive leakage from the Repsol's floating dock in the port of Tarragona • The biggest oil spill ever occurred in the Eastern Mediterranean Sea: the 2006 Lebanon oil spill. In both cases, the new version of SIMOIL, demonstrate more accurate predictions of the behaviour of the oil spill, specially for moderate winds with complex topography.La contaminación generada por los vertidos accidentales de petróleo puede ser reducida si se actúa y si se toman las decisiones adecuadas a tiempo. Las simulaciones numéricas de vertidos de petróleo permiten predecir la evolución de las manchas de crudo. En este trabajo, el objetivo principal era de mejorar la precisión y el rango de aplicación del código SIMOIL desarrollando e integrando al código un modelo de predicción de corrientes marinas en aguas costeras. Se han derivado las ecuaciones de aguas poco profundas en coordenadas generalizadas. Se han discretizado las ecuaciones y el código se implementó en FORTRAN 90. El modelo así como los métodos numéricos han sido validados con el estudio de flujos experimentales y numéricos de la bibliografía. Finalmente, la nueva versión de SIMOIL se aplicó con éxito a dos casos físicos de vertidos de crudo: • un vertido ficticio desde la monoboya de descarga de Repsol en el puerto de Tarragona • un vertido real, el mas grande ocurrido en el Este del mar Mediterráneo, consecuencia de la guerra en Líbano en julio de 2006. En ambos casos la nueva versión de SIMOIL proporcionó predicciones más precisas, especialmente para vientos moderados y topografías complejas

MEDSLIK-II, a Lagrangian marine surface oil spill model for short-term forecasting – Part 2: Numerical simulations and validations

Abstract. In this paper we use MEDSLIK-II, a Lagrangian marine surface oil spill model described in Part 1 (De Dominicis et al., 2013), to simulate oil slick transport and transformation processes for realistic oceanic cases, where satellite or drifting buoys data are available for verification. The model is coupled with operational oceanographic currents, atmospheric analyses winds and remote sensing data for initialization. The sensitivity of the oil spill simulations to several model parameterizations is analyzed and the results are validated using surface drifters, SAR (synthetic aperture radar) and optical satellite images in different regions of the Mediterranean Sea. It is found that the forecast skill of Lagrangian trajectories largely depends on the accuracy of the Eulerian ocean currents: the operational models give useful estimates of currents, but high-frequency (hourly) and high-spatial resolution is required, and the Stokes drift velocity has to be added, especially in coastal areas. From a numerical point of view, it is found that a realistic oil concentration reconstruction is obtained using an oil tracer grid resolution of about 100 m, with at least 100 000 Lagrangian particles. Moreover, sensitivity experiments to uncertain model parameters show that the knowledge of oil type and slick thickness are, among all the others, key model parameters affecting the simulation results. Considering acceptable for the simulated trajectories a maximum spatial error of the order of three times the horizontal resolution of the Eulerian ocean currents, the predictability skill for particle trajectories is from 1 to 2.5 days depending on the specific current regime. This suggests that re-initialization of the simulations is required every day

Line-of-sight iceberg edge-following using an AUV equipped with multibeam sonar

Obtaining 3D information about ice features, like icebergs, are of interest to researchers and offshore operators moving into the Arctic. Icebergs are affected by wind, and ocean currents, and can have unpredictable drift patterns, causing challenges when it comes to mapping objectives. Autonomous underwater vehicles (AUVs) equipped with multibeam echosounders are suitable for obtaining measurements of the underwater geometry of icebergs, but advances in autonomy are needed to map drifting icebergs reliably. This paper details a guidance algorithm for detecting and circumnavigating an iceberg - following the iceberg edge. The guidance scheme is implemented as a state machine, starting in an iceberg detection-mode. Once an iceberg is detected, the AUV will enter a mapping-mode. An edge detection algorithm will determine the position of the edge, and a line-of-sight approach will be used for edge-following. A six degree-of-freedom AUV simulator is used to perform a simulation study, to show how AUV dynamics affect the results. The simulation study presented shows the algorithm's effectiveness, both when the iceberg is assumed stationary, and when the iceberg is drifting and rotating with constant velocity

Multiscale, Multiphysics Modelling of Coastal Ocean Processes: Paradigms and Approaches

This Special Issue includes papers on physical phenomena, such as wind-driven flows, coastal flooding, and turbidity currents, and modeling techniques, such as model comparison, model coupling, parallel computation, and domain decomposition. These papers illustrate the need for modeling coastal ocean flows with multiple physical processes at different scales. Additionally, these papers reflect the current status of such modeling of coastal ocean flows, and they present a roadmap with numerical methods, data collection, and artificial intelligence as future endeavors

Self-Evaluation Applied Mathematics 2003-2008 University of Twente

This report contains the self-study for the research assessment of the Department of Applied Mathematics (AM) of the Faculty of Electrical Engineering, Mathematics and Computer Science (EEMCS) at the University of Twente (UT). The report provides the information for the Research Assessment Committee for Applied Mathematics, dealing with mathematical sciences at the three universities of technology in the Netherlands. It describes the state of affairs pertaining to the period 1 January 2003 to 31 December 2008

17. Simpozij „Materijali i metalurgija“ – dopuna „Zbornik sažetaka”

In Metalurgija 63 (2024) 2,303-320 published „ Book of Abstracts “ (224). Deadline for received of Abstracts was November, 30,2023 y. Many authors have request new deadline by March, 25, 2024 y. Organizing committee have accept new deadline. Now it published supplements of 103 Abstracts.U Metalurgiji 63 (2024) 2,303-320 objavljen je Zbornik sažetaka (224). Rok za primitak sažetke je bio 30. studeni 2023. god. Mnogi autori zatražili novi rok do 25.03.2024. Organizacijski odbor Simpozija je prihvatio novi termin. Objavljuje se sada dodatnih još 160 sažetaka