José Simão Antunes Do Carmo

By José Simão Antunes do Carmo

Part of the book: Advanced Fluid Dynamics

By José Simão Antunes do Carmo

Numerical models are a useful instrument for studying complex superposition of wave–wave and wave–current interactions in coastal and estuarine regions and to investigate the interaction of waves with complex bathymetries or structures built in nearshore areas. Moreover, since their applications are significantly less expensive and more flexible than the construction of physical models, they are a convenient tool to support design. The ability of the standard Boussinesq and Serre or Green and Naghdi equations to reproduce these nonlinear processes is well known. However, these models are restricted to shallow water conditions, and addition of other terms of dispersive origin has been considered since the 1990s, particularly for approximations of the Boussinesq-type. To allow applications in a greater range of h0 / λ, other than shallow waters, where h0 is the water depth at rest and λ is the wavelength, a new set of Serre-type equations, with additional terms of dispersive origin, is developed and tested with the available data and with a numerical solution of a Boussinesq-type model, also improved with dispersive characteristics. Explicit and implicit methods of finite–difference are implemented to solve both approximations of Boussinesq and Serre types with improved dispersive characteristics. A finite element method is also implemented to solve an extension of a Boussinesq-type model that takes into account wave–current interactions. Application examples to solve real-world problems are shown and discussed. The performances of both 1HD models are compared with experimental data of very demanding applications, namely: (i) a highly nonlinear solitary wave propagating up a slope and reflecting from a vertical wall and (ii) a periodic wave propagating in intermediate-depth waters upstream a trapezoidal bar, followed by very shallow waters over the bar, and again in intermediate-depth water conditions downstream.

Part of the book: New Perspectives in Fluid Dynamics

By José Simão Antunes do Carmo

In the recent past, coastal public works solutions were generally designed as engineering problems. By that time, prior to the 1980s, the primary goal of coastal works projects was to maximize safety, taking into account only engineering knowledge and existing economic constraints. Today, concerns are no longer limited to safety; lifestyle and quality of life have become essential ingredients in building a successful coastal works project. Other aspects of the project are also important, such as environmental impact, attractiveness, and sustainability. These additionalcomplexities are further aggravated by other pieces of the puzzle that need to be integrated into the overall design, such as the non-engineering and non-science aspects. A synthesis of recent concerns regarding coastal public works projects has, in fact, become much more difficult for engineers to manage due to new assumptions of value, social acceptance, and sustainability of these projects. In this context, it is common knowledge that decision-making on a coastal issue should be based on criteria such as technical effectiveness, costs, benefits, implementation, and monitoring. This chapter addresses coastal issues using a dual perspective of meeting current needs and ensuring future sustainability. Contemporary adaptation measures and future accommodation options are also discussed.

Part of the book: Coastal and Marine Environments

By José Simão Antunes Do Carmo

In March 2001, a serious accident occurred in Portugal during a flood on the Douro River, next to Porto, Portugal. The collapse of the Hintze Ribeiro Bridge killed 59 people traveling in a bus and in three cars that fell into the Douro River. This bridge was built at the end of the 19th century on a curve of the Douro River, next to the mouth of the Tâmega River, approximately 50 km upstream of Porto. It was found that the combined effects of sand dredging in the 25 years prior to the accident (1975–2000) and the erosion produced by five consecutive floods between December 2000 and March 2001 were the main causes of this accident. Aiming to contribute to the prevention of occurrences such as that registered in Portugal with the collapse of the Hintze Ribeiro Bridge, a brief overview of this bridge is presented herein, as well as the causes that led to the collapse, some reflections on the processes involved, and, mainly, the lessons learned.

Part of the book: River Basin Management