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Development of control system for generation and active absorption of waves in offshore structures test tanks.

Full text
Author(s):
Mario Luis Carneiro
Total Authors: 1
Document type: Doctoral Thesis
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Escola Politécnica (EP/BC)
Defense date:
Examining board members:
Eduardo Aoun Tannuri; Paulo de Tarso Themistocles Esperança; Fuad Kassab Junior; Alexandre Nicolaos Simos; Adriano Almeida Gonçalves Siqueira
Advisor: Eduardo Aoun Tannuri
Abstract

This work presents the development of a control system for active absorption of waves as part of the implementation of a new test tank of ocean structures at the University of São Paulo. The tank is equipped with 148 wave generators disposed around its perimeter to allow the generation of waves in all directions. The implemented method of wave absorption is based on digital filters with hydrodynamic feedback given by level sensors solidary to the wave generator. Were studied recursive and non-recursive, one-dimensional and two-dimensional filters. A method for stability analysis of the closed loop control system it is also presented. To evaluate the performance of the absorption control system, a series of experiments was performed considering regular waves with propagation direction normal to the wave generator and some oblique directions. Were also performed tests with irregular waves with propagation direction normal to the wave generator. The experimental reflection coefficient obtained showed good adherence to the theoretical values, presenting a maximum of 5.61% for an angle of incidence between 0o to 45o in the frequency range of operation of the tank. In tests with oblique waves was observed the appearance of a lateral wave resonance with highest frequency of the generated wave, prohibiting the accomplishment of long term experiments of waves with different incidence angle of 0o. At the end it is made suggestions to correct this problem. (AU)

FAPESP's process: 08/06428-4 - Development of control system for waves generation and active absorption in oceanic structures test tanks
Grantee:Mario Luis Carneiro
Support Opportunities: Scholarships in Brazil - Doctorate