Experimental studies on the flow characteristics in an oscillating water column device

A fixed type oscillating water column (OWC) device was designed and tested in a 2-D wave channel. The air chamber was converged to its minimum area at the turbine section to obtain the maximum kinetic energy. The variations in the height of water in the water column and in the static pressure of the air caused by the oscillating waves were studied in detail. The airflow in the entire air chamber was documented with particle image velocimetry measurements. No turbine was installed in the device. The experiments were performed by varying the water depth and the wave frequency. It was found that the air velocities in the turbine chamber during the upward motion of water in the column are always larger than during the downward motion. While the airflow was strong most of the time, very low air velocities were recorded during the transition between the upward and downward flows indicating the need of an airflow regulator before the turbine to get a constant flow rate of air. The well-directed flow obtained at the turbine section can be used to drive a Savonius rotor, which is the most appropriate turbine for rectangular cross-section of the chamber.

[1]  J. M. Paixão Conde,et al.  Numerical study of the air-flow in an oscillating water column wave energy converter , 2008 .

[2]  C. Greated,et al.  The application of particle image velocimetry to the study of water waves , 1988 .

[3]  Markus Raffel,et al.  Particle Image Velocimetry: A Practical Guide , 2002 .

[4]  B. Lemehaute.  An introduction to hydrodynamics and water waves , 1976 .

[5]  Johannes Falnes,et al.  A REVIEW OF WAVE-ENERGY EXTRACTION , 2007 .

[6]  S. Elgar.  Waves in Oceanic and Coastal Waters , 2007 .

[7]  S. Pond,et al.  Introductory Dynamical Oceanography , 1983 .

[8]  D. Dorrell,et al.  Investigation of a small-scale segmented oscillating water column utilizing a Savonius rotor turbine , 2006 .

[9]  D. Evans,et al.  HYDRODYNAMIC CHARACTERISTICS OF AN OSCILLATING WATER COLUMN DEVICE , 1995 .

[10]  David R. Basco,et al.  Water Wave Mechanics for Engineers and Scientists , 1985 .

[12]  Manabu Takao,et al.  Current status of self rectifying air turbines for wave energy conversion , 2006 .

[13]  R. Fujita,et al.  Renewable energy from the ocean , 2002 .

[14]  L. Lourenço.  Particle Image Velocimetry , 1989 .

[15]  C. Josset,et al.  A time-domain numerical simulator for oscillating water column wave power plants , 2007 .

[16]  M. Mccormick.  Ocean Wave-Energy Conversion , 2019, Encyclopedia of Ocean Sciences.

[17]  Manabu Takao,et al.  A review of impulse turbines for wave energy conversion , 2001 .

[18]  Anthony Lewis,et al.  3D hydrodynamic modelling of fixed oscillating water column wave power plant by a boundary element methods , 2003 .

[19]  Burçin Deda Altan,et al.  The use of a curtain design to increase the performance level of a Savonius wind rotors , 2010 .

[20]  Paulo Alexandre Justino,et al.  OWC wave energy devices with air flow control , 1999 .

[21]  A. J. N. A. Sarmento,et al.  Wave flume experiments on two-dimensional oscillating water column wave energy devices , 1992 .

[22]  Jean-Luc Menet,et al.  A double-step Savonius rotor for local production of electricity: a design study , 2004 .

[23]  P. A. Aswatha Narayana,et al.  Model Studies of Oscillating Water Column Wave-Energy Device , 1995 .

[24]  Manabu Takao,et al.  A modified Wells turbine for wave energy conversion , 2003 .