Browsing by Author "Sanchez-Lara, M."
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Item Experimental studies on the hydrodynamic behavior of a semi-submersible offshore wind platform(CRC Press/Balkema, 2015) Nava, V.; Aguirre, G.; Galvan, J.; Sanchez-Lara, M.; Mendikoa, I.; Perez-Moran, G.; Soares, C. Guedes; RENOVABLES OFFSHORE; Tecnalia Research & InnovationIn this paper, the major results of an experimental tank test campaign on the hydrodynamics and dynamics of a floating offshore semisubmersible platform supporting a wind energy turbine are presented. The tests were performed by TECNALIA at the HMRC wave tank in Cork within the framework of the MARINET project. The prototype consisted in a four-column semisubmersible platform with a ring pontoon placed in 60-m-deep water and subject to a wave climate typical of the Basque Country coast; the tests were performed using a small (1:60) physical model following Froude scaling law. The turbine held by the prototype is the NREL 5MW baseline wind turbine. Mainly the investigation dealt with the identification of the characteristics of the platform: the results herein presented include outcomes from decay tests, response amplitude operators (RAOs) by means of tests in regular waves, irregular wave responses and fairlead mooring loads. The purpose of the work is to achieve a comprehensive system identification of the major properties of the platform; further, the experimental results have been used to validate the modeling of the structure and to compare them with the outcomes of numerical simulations obtaining by coupling commercial software and other data available in literature.Item Numerical investigation of the aerodynamic performance for a wells-type turbine in a wave energy converter(International Center for Numerical Methods in Engineering, 2015) Stipcich, G.; Ramezani, A.; Nava, V.; Touzon, I.; Sanchez-Lara, M.; Remaki, L.; Muscari, Roberto; Broglia, Riccardo; Salvatore, Francesco; RENOVABLES OFFSHORE; Tecnalia Research & InnovationOcean waves constitute an extensive energy resource, whose extraction has been the subject of intense research activity in the last three decades. Among the different variants of Wave Energy Converters, the principle of the Oscillating Water Column (OWC) is one of the most promising ones. An OWC comprises two key elements: A collector chamber, which transfers the wave oscillations' energy to the air within the chamber by back and forth displacement, and a power take off system, which converts the pneumatic power into electricity or some other usable form. The Wells turbine is a self-rectifying air turbine, a suitable solution for energy extraction from reciprocating air flow in an OWC. In the present work, the steady state, inviscid flow in the Wells turbine is investigated by numerical simulations. The relatively novel Virtual Multiple Reference Frame (VMRF) technique is used to account for the rotary motion of the turbine, and the overall performance is compared with results in the literature.