M. F. P. Lopes

Spinverse · Energy

Power production levels at the Pico plant fall significantly short of pre-project estimates. Poor turbine performance compared to expectations from scale model testing accounts for much of this shortfall. Unanticipated chamber pressure skewness is also found to contribute to the deficit. This skewness manifests from wave shoaling because of the sha...

Results from laboratory experiments on a pre-tensioned heaving buoy of 8.4 m diameter, tested at scale 1:16 is presented. The wave energy converter, which is under development by the Swedish company CorPower Ocean, is designed with a passive pneumatic machinery component referred to as WaveSpring, invented at NTNU. The negative spring arrangement i...

Results from laboratory experiment of a pre-tensioned heaving buoy of 8.4 m diameter, tested at scale 1:16 is presented. The wave energy converter, which is under development by the Swedish company CorPower Ocean, is designed with a passive pneumatic machinery component referred to as WaveSpring, invented at NTNU. The negative spring arrangement in...

The real-time control of wave energy converters (WECs) requires the prediction of the wave elevation at the location of the device in order to maximize the power extracted from the waves. One possibility is to predict the future wave elevation by combining its past history with the spatial information coming from a sensor which measures the free su...

This paper presents a numerical study on the hydrodynamics of bottom-hinged plate wave energy converters in regular and irregular waves. A parametric analysis of the plate width and height was performed. Both fully submerged and surface-piercing plates were considered. Two distinct models were developed based on linear hydrodynamics. The first one,...

The shore mounted “Pico” OWC has a relief valve mounted in parallel to the turbine which connects the chamber to the atmosphere. The aperture of this valve is adjustable and can be used to regulate the pneumatic power exposed to the turbine. Here we develop an algorithm to actively control the relief valve aperture so that the peak pneumatic power...

Although the latching control strategy has been recognized as an important mean of increasing the efficiency of one-body point-absorbing wave energy converters (WECs), its effectiveness in two-body floating point-absorbers has been questioned in some studies. The current work investigates the annual power conversion increase achieved with a simple...

This paper studies the wave energy conversion by fully-submerged bottom-hinged plates of finite width. In this study, linear water wave theory was considered, and the hydro-dynamic coefficients were computed using a three-dimensional boundary element method. The plate was modelled as a zero-thickness plate rotating about an axis located on the seab...

Eddy current brakes provide a versatile way of simulating the power take-off system (PTO) in model testing of small scale wave energy converters (WECs). This type of PTO simulator is based on the principle that a conductive material moving in a magnetic field generates a braking force proportional to its velocity. A bottom-hinged pitching plate WEC...

When designing structures to the wind action, the variation of the mean wind velocity and turbulence parameters with the height above the ground must be taken into account. This paper presents the numerical simulation results of atmospheric boundary layer (ABL) airflows, in a numerical domain with no obstacles and with a cubic building. The results...

Eddy current brakes provide a versatile way of simu-lating the power take-off system (PTO) in the model test-ing of wave energy converters at small scale. These are based on the principle that a conductive material moving perpendicularly to a magnetic field generates a braking force proportional to its velocity. This was applied in the design of th...

Phase control may substantially increase the power absorption in point-absorber wave energy converters. This study deals with validation of dynamic models and latching control algorithms for an oscillating water column (OWC) inside a fixed vertical tube of small circular cross-section by small-scale testing. The paper describes experimental and num...

The growing requirements for renewable energy production lead to the development of a new series of systems, including wave energy conversion systems. Due to their sensitivity and the impact of the aggressive marine environment, the selection of the most adequate location for these systems is a major and very important task. Several factors, such a...

Apresenta-se a análise de resultados dos ensaios experimentais, em tanque de ondas, de um modelo à escala reduzida do flutuador de um dispositivo em desenvolvimento no IST. De forma a introduzir o tema apresenta-se uma curta pesquisa das tecnologias existentes para a conversão de energia das ondas em energia eléctrica. Para permitir a análise dos r...

A simulation on the Atmospheric Boundary layer (ABL) was done in a short wind tunnel that is based on the Irwin method. This simulation should be in accordance with the conditions described in the Eurocode 1 (EC1) in order that general studies can be done in the future regarding wind actions on buildings. The combination of triangular spires and th...

This paper presents an experimental and numerical study of the two-dimensional wave diffraction by a fixed horizontal-axis submerged circular cylinder. The objective of the paper is to report and validate the results from the fully non-linear two-dimensional boundary-element method code CANAL and to assess the capability of the physical wave flume...