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Abstract(s)
Métodos de Mapeamento Conforme: Desenvolvimento de uma Ferramenta Computacional para o Cálculo de Coe cientes Hidrodinâmicos
A análise do comportamento de um navio no mar (seakeeping) é uma área importante da Engenharia Oceânica e da Arquitetura Naval, permitindo-nos prever o comportamento do navio em ondas nos seus seis graus de liberdade acoplados. O problema da previsão do comportamento do navio no mar é uma tarefa complexa, abordando várias áreas, geralmente exigindo ferramentas de computação. Um deles é o problema da radiação, que será discutido ao longo do trabalho.
Inicialmente, serão abordados alguns conceitos básicos da dinâmica do navio e da Teoria das Faixas.
Como o primeiro passo na solução do problema de radiação através de métodos de mapeamento conforme é encontrar uma função mapeadora adequada que transforme uma secção circular na secção transversal real do navio, este trabalho abordará alguns aspectos dessa área. Dos diferentes métodos clássicos disponíveis, serão aplicados o Método de Transformação de Lewis que utiliza dois parâmetros, e o Método de Transformação Conforme Multiparâmetro.
Reconhecendo a necessidade de um método simples e barato para estimativas iniciais e/ou rápidas, foi desenvolvida uma ferramenta computacional em Matlab R para o cálculo de coe cientes hidrodinâmicos de uma secção de um navio, baseada no Método de Mapeamento Conforme ou Método de Lewis.
Finalmente, a ferramenta acima mencionada não foi apenas validada usando dados da literatura, mas também aplicada para encontrar estimativas aproximadas dos coe cientes hidrodinâmicos locais e globais de uma fragata da Marinha Portuguesa.
Conformal Mapping Methods: Development of a Computing Tool for the Calculation of Hydrodynamic Coe¢ cients Seakeeping is an important area of Ocean Engineering and Naval Archi- tecture, allowing us to predict the ship s behavior in waves in its coupled six degrees of freedom. Seakeeping problem is a complex task, addressing several areas, usually requiring computing tools. One of them is the radia- tion problem, which will be discussed throughout the work. Initially this paper will address the basic concepts of the ship dynamics and the Strip Theory. Because the rst step in the solution of the radiation problem through conformal mapping methods is nding a proper conformal mapping function that transforms a circular section into the actual ship cross section, this work will address some aspects of this area. Among the di¤erent classic methods available, it will be applied the Lewis Transformation Method which use two parameters, and the Multiparameter Conformal Transformation Method. Recognizing the need for a simple and inexpensive method for initial and/or quick estimates, it was developed a computation tool in Matlab R for the calculation of the hydrodynamic coe¢ cients of a ship section, based on the Conformal Mapping Method or Lewis Method. Finally, the above-mentioned tool was not only validated using literature data, but also applied to nd rough estimates of the local and global hydrodynamic coe¢ cients of a Portuguese Navy frigate.
Conformal Mapping Methods: Development of a Computing Tool for the Calculation of Hydrodynamic Coe¢ cients Seakeeping is an important area of Ocean Engineering and Naval Archi- tecture, allowing us to predict the ship s behavior in waves in its coupled six degrees of freedom. Seakeeping problem is a complex task, addressing several areas, usually requiring computing tools. One of them is the radia- tion problem, which will be discussed throughout the work. Initially this paper will address the basic concepts of the ship dynamics and the Strip Theory. Because the rst step in the solution of the radiation problem through conformal mapping methods is nding a proper conformal mapping function that transforms a circular section into the actual ship cross section, this work will address some aspects of this area. Among the di¤erent classic methods available, it will be applied the Lewis Transformation Method which use two parameters, and the Multiparameter Conformal Transformation Method. Recognizing the need for a simple and inexpensive method for initial and/or quick estimates, it was developed a computation tool in Matlab R for the calculation of the hydrodynamic coe¢ cients of a ship section, based on the Conformal Mapping Method or Lewis Method. Finally, the above-mentioned tool was not only validated using literature data, but also applied to nd rough estimates of the local and global hydrodynamic coe¢ cients of a Portuguese Navy frigate.
Description
Keywords
Formas de Lewis Coeficientes hidrodinâmicos Teoria das Faixas Mapeamento conforme Lewis forms Hydrodynamic coeficients Strip Theory Conformal mapping