Characteristics of orifices for modeling nonlinear power take-off in wave-flume tests of oscillating water column devices
| Autor: | Zhenhua Huang, Fang He |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Engineering
business.industry 020209 energy General Engineering Oscillating Water Column 02 engineering and technology Mechanics 01 natural sciences Pressure coefficient 010305 fluids & plasmas law.invention Physics::Fluid Dynamics Borda–Carnot equation Pressure measurement Wave flume Control theory law 0103 physical sciences 0202 electrical engineering electronic engineering information engineering Power take-off business Body orifice Wave power |
| Zdroj: | Journal of Zhejiang University-SCIENCE A. 18:329-345 |
| ISSN: | 1862-1775 1673-565X |
| DOI: | 10.1631/jzus.a1600769 |
| Popis: | Oscillating water column (OWC) devices for wave power extraction are appealing, but are still in need of research. In this study, a series of wave-flume experiments was conducted to examine the hydrodynamic performance of a rectangular OWC device fixed in regular waves. Two types of orifices, slot orifices and circular orifices, were used to simulate the nonlinear power take-off (PTO) mechanism, and the effects of orifice geometry were examined. A two-point measurement method was proposed to reconstruct the instantaneous spatial profile of the water surface inside the OWC chamber for reducing bias in the measured wave power extraction efficiency. The flow characteristics of PTO were described by a quadratic loss coefficient, and our experimental results showed that the quadratic loss coefficient of the slot orifices varied with wave period and slot geometry. Empirical formulas were proposed for the quadratic loss coefficients of the two types of orifices. The ability to determine the quadratic loss coefficient of an orifice will allow us to design orifices for small-scale tests and calculate the power extraction using only pressure measurement. Our results also suggested that the pressure coefficient should be more reliable than the amplification coefficient as an indicator of the power extraction performance of an OWC device. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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