# Experimental Investigation of the Flow Field in the Vicinity of an Oscillating Wave Surge Converter

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## Abstract

**:**

## 1. Introduction

## 2. Experimental Setup and Procedures

#### 2.1. Wave Flume

#### 2.2. OWSC Model

#### 2.3. Full Experimental Setup and Instrumentation

#### 2.4. Data Collection

#### 2.5. Repeatability of Experimental Tests

#### 2.6. Data Analysis

## 3. Laboratory Evidence and Linear Wave Theory

#### 3.1. Dynamic Equilibrium

#### 3.2. Hydrodynamic Torque: Experimental and Analytical Results

#### 3.3. Dynamics of OWSC: Comparison between Experimental and Analytical Results

## 4. Mean and Turbulent Flow Field in Front of the OWSC

## 5. Conclusions

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## Abbreviations

OWSC | oscillating wave surge converter |

PTO | power take-off |

UVP | ultrasonic velocity profiler |

WP | wave probe |

UP | ultrasonic velocity profiler probe |

RO | rated output |

PPR | pulses per revolution |

## Appendix A. Analytical Hydrodynamic Parameters

## Appendix B. Friction Force Model

## References

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**Figure 2.**Layout of the OWSC model, illustrating: the position of the experimental setup; the configuration of the UVP probes (UP1, UP2 and UP3); and the geometry of the OWSC.

**Figure 5.**Full time series of normalized (

**a**) free-surface elevation and (

**b**) rotation angle of the flap. The dash-dotted line represents the amplitude scales. The vertical line at $t/T=35$ indicates the beginning of the quasi-steady condition.

**Figure 6.**Time series for $65<t/T<75$ of normalized (

**a**) free-surface elevation, (

**b**) rotation angle of the flap, (

**c**) pressure in the cylinder chamber, and (

**d**) angular velocity of the flap. Dash-dotted lines represent the amplitude scale.

**Figure 7.**Comparison between measured and fitted torque due to the pressure force of the hydraulic cylinder for (

**a**) $T=3.5$ s and $H=0.25$ m, (

**b**) $T=2.5$ s and $H=0.2$ m.

**Figure 8.**Comparison between experimental and analytical variations of the amplitude of hydrodynamic torque with a wave period.

**Figure 9.**Comparison between experimental and analytical variation of (

**a**) amplitude of rotation angle of the flap and (

**b**) power capture factor with the wave period.

**Figure 10.**Comparison between experimental and analytical phase-averaged of normalized (

**a**) free-surface elevation, (

**b**) rotation, (

**c**) power capture, and (

**d**) angular velocity of the flap.

**Figure 11.**Experimental phase-averaged velocity vector field and contour of longitudinal velocity normalized by ${U}_{0}$ at (

**a**) $t/T=0$, (

**b**) $t/T=0.06$, (

**c**) $t/T=0.15$, (

**d**) $t/T=0.27$, (

**e**) $t/T=0.38$, and (

**f**) $t/T=0.44$.

**Figure 12.**Longitudinal and vertical phase-averaged velocity profiles normalized by ${U}_{0}$ at $x/h=-0.11$ and (

**a**) $t/T=0$, (

**b**) $t/T=0.06$, (

**c**) $t/T=0.15$, (

**d**) $t/T=0.27$, (

**e**) $t/T=0.38$, and (

**f**) $t/T=0.44$.

T (s) | H (m) | ${\mathit{x}}_{12}$ (m) | ${\mathit{x}}_{23}$ (m) |
---|---|---|---|

2 | [0.15; 0.175; 0.2; 0.225; 0.25; 0.275; 0.3] | 0.49 | 1.23 |

2.25 | [0.15; 0.175; 0.2; 0.225; 0.25; 0.275; 0.3] | 0.57 | 1.42 |

2.5 | [0.15; 0.175; 0.2; 0.225; 0.25; 0.275; 0.3] | 0.65 | 1.62 |

2.75 | [0.15; 0.175; 0.2; 0.225; 0.25; 0.275; 0.3] | 0.72 | 1.81 |

3 | [0.15; 0.175; 0.2; 0.225; 0.25; 0.275; 0.3] | 0.8 | 2 |

3.25 | [0.15; 0.175; 0.2; 0.225; 0.25; 0.275; 0.3] | 0.88 | 2.19 |

3.5 | [0.15; 0.175; 0.2; 0.225; 0.25; 0.275; 0.3] | 0.95 | 2.38 |

3.75 | [0.15; 0.175; 0.2; 0.225; 0.25; 0.275; 0.3] | 1.02 | 2.56 |

4 | [0.15; 0.175; 0.2; 0.225; 0.25; 0.275; 0.3] | 1.1 | 2.75 |

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**MDPI and ACS Style**

Brito, M.; Ferreira, R.M.L.; Teixeira, L.; Neves, M.G.; Gil, L. Experimental Investigation of the Flow Field in the Vicinity of an Oscillating Wave Surge Converter. *J. Mar. Sci. Eng.* **2020**, *8*, 976.
https://doi.org/10.3390/jmse8120976

**AMA Style**

Brito M, Ferreira RML, Teixeira L, Neves MG, Gil L. Experimental Investigation of the Flow Field in the Vicinity of an Oscillating Wave Surge Converter. *Journal of Marine Science and Engineering*. 2020; 8(12):976.
https://doi.org/10.3390/jmse8120976

**Chicago/Turabian Style**

Brito, Moisés, Rui M. L. Ferreira, Luis Teixeira, Maria G. Neves, and Luís Gil. 2020. "Experimental Investigation of the Flow Field in the Vicinity of an Oscillating Wave Surge Converter" *Journal of Marine Science and Engineering* 8, no. 12: 976.
https://doi.org/10.3390/jmse8120976