scholarly journals Numerical Modeling Tools Applied to Estuarine and Coastal Hydrodynamics: A User Perspective

Author(s):  
Isabel Iglesias ◽  
Paulo Avilez-Valente ◽  
José Luís Pinho ◽  
Ana Bio ◽  
José Manuel Vieira ◽  
...  
Geophysics ◽  
2009 ◽  
Vol 74 (4) ◽  
pp. T55-T66 ◽  
Author(s):  
Fabian Wenzlau ◽  
Tobias M. Müller

Numerical modeling of seismic waves in heterogeneous, porous reservoir rocks is an important tool for interpreting seismic surveys in reservoir engineering. Various theoretical studies derive effective elastic moduli and seismic attributes from complex rock properties, involving patchy saturation and fractured media. To confirm and further develop rock-physics theories for reservoir rocks, accurate numerical modeling tools are required. Our 2D velocity-stress, finite-difference scheme simulates waves within poroelastic media as described by Biot’s theory. The scheme is second order in time, contains high-order spatial derivative operators, and is parallelized using the domain-decomposition technique. A series of numerical experiments that are compared to exact analytical solutions allow us to assess the stability conditions and dispersion relations of the explicit poroelastic finite-differ-ence method. The focus of the experiments is to model wave-induced flow accurately in the vicinity of mesoscopic heterogeneities such as cracks and gas inclusions in partially saturated rocks. For that purpose, a suitable numerical setup is applied to extract seismic attenuation and dispersion from quasi-static experiments. Our results confirm that finite-difference modeling is a valuable tool to simulate wave propa-gation in heterogeneous poroelastic media, provided the temporal and spatial scales of the propagating waves and of the induced fluid-diffusion processes are resolved properly.


Author(s):  
Zhiqun Daniel Deng ◽  
Thomas J. Carlson ◽  
Gene R. Ploskey ◽  
Richard S. Brown ◽  
Gary E. Johnson ◽  
...  

Author(s):  
Nina I. Eremeeva

The COVID-19 epidemic has once again demonstrated the importance of predicting the development of various processes and calculating the consequences. “How effective is the introduction of strict quarantine measures?” and “Will the quarantine be able to stop the epide­mic?” — these questions still have no clear answer. This article aims to answer these questions using mathematical modeling tools using the SEIRD model, modified to account for the peculiarities of the spread of COVID-19. The SEIRD model belongs to the class of differential dynamic models, which allows quick experimentation to predict the spread of the disease and calculate its influence on the development of certain processes. Based on numerical modeling, the author demonstrates that insufficient quarantine measures provide only a temporary effect. After they end, with an insufficient level of “population immunity”, the epidemic starts growing again, leading to a second morbidity peak. This paper presents numerical calculations to track the duration impact and quarantine measures’ severity on the dynamics of the epidemiological process. The results show that strict restrictive measures are not always effective, and strict short-term measures have less effect than softer, but long-term measures. In addition, the author provides an example of finding the parameters of quarantine measures that ensure fixed limits on the morbidity level during the epidemic.


Shore & Beach ◽  
2019 ◽  
pp. 36-43
Author(s):  
Peter Ruggiero ◽  
Nicholas Cohn ◽  
Bas Hoonhout ◽  
Evan Goldstein ◽  
Sierd de Vries ◽  
...  

Despite the importance of coastal dunes to many low-lying coastal communities and ecosystems, our understanding of how both climatic and anthropogenic pressures affect foredune evolution on time scales of years to decades is relatively poor. However, recently developed coupled numerical modeling tools have allowed for the exploration of the erosion and growth of coastal foredunes on time scales of hours to years. For example, Windsurf is a new process-based numerical modeling system (Cohn et al. 2019a) that simulates the evolution of dune-backed sandy coastal systems in response to wave, wind, and water level forcings. CReST, developed as a front-end interface to Windsurf, aims to add the ability to incorporate beach nourishment and dune construction, beach and dune grading, dune grass planting scenarios, dune grass removal, and the presence of hard engineering structures into the model framework to better account for the complex dynamics of managed coastlines. Initial model sensitivity tests suggest that the model provides a flexible framework to investigate the complex interactions between beaches and dunes for a variety of exploratory and applied applications.


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