scholarly journals ON THE EFFECTIVENESS OF OSCILLATING WATER COLUMN DEVICES IN REDUCING THE AGITATION IN FRONT OF VERTICAL WALLS HARBOR STRUCTURES

2018 ◽  
pp. 112
Author(s):  
Lorenzo Cappietti ◽  
Irene Simonetti
Keyword(s):  
Numerical Simulations ◽  
Wave Field ◽  
Water Column ◽  
Methodological Approach ◽  
Vertical Wall ◽  
Design Parameters ◽  
Oscillating Water Column ◽  
Port Area ◽  
Vertical Walls ◽  
Reflective Systems

Reducing wave reflection at vertical wall harbor structures is an important goal to ease mooring and maneuvering inside the port area. In this study, numerical simulations have been carried out to assess the effectiveness of Oscillating Water Column devices as anti-reflective systems to be integrated in vertical wall harbor structures. The numerical simulations have been carried out in a Numerical Wave Tank, implemented in the Computational Fluid Dynamics environment OpenFOAM®. A methodological approach to separate the reflected and the radiated wave components is presented. The interaction (destructive/constructive interference) between the reflected and the radiated wave field is studied. Furthermore, a preliminary assessment of the effect of basic design parameters of the Oscillating Water Column on the wave field in front of the structure is discussed. A relatively good performance of the device is found, with a minimum reflection coefficient of around 15%, suggesting that the device could efficiently be used to reduce wave agitation in front of vertical wall harbor structures.

scholarly journals ON THE EFFECTIVENESS OF OSCILLATING WATER COLUMN DEVICES IN REDUCING THE AGITATION IN FRONT OF VERTICAL WALLS HARBOR STRUCTURES

2018 ◽  
Vol 1 (36) ◽  
pp. 67
Author(s):  
Lorenzo Cappietti ◽  
Irene Simonetti
Keyword(s):  
Water Column ◽  
Wave Reflection ◽  
Vertical Wall ◽  
Oscillating Water Column ◽  
Energy Converter ◽  
Deep Waters ◽  
Wall Structures ◽  
Vertical Walls ◽  
Rubble Mound ◽  
Effective Use

Wave reflection at harbor structures negatively affects the navigability of entrance canals and harbor tranquility. In case of rubble-mound structures this phenomenon is relatively limited if compared to vertical-wall structures. However, in case of deep waters, the use of the latter is an obliged choice due to economic reasons. Furthermore, vertical wall structures are also the preferred choice of harbor managers since they permit a better design of the berthing structures and help the effective use of space inside the harbor. Reducing the wave reflection at vertical wall structures is thus an important measure. To date, several approaches have been presented in the literature (see for instance Huang et al., 2011, and references therein). The effectiveness of slotted vertical perforated-walls has been studied since many years (most recently: Neelamani et al., 2017). Such kind of structure is often also adopted as frontal and internal wall of caisson breakwaters embodying one or multiple chambers (most recently: Ciocan et al., 2017). Another alternative, so far proposed, are caissons with internal rubble mound (Altomare, C., & Gironella, X., 2014). The so called Oscillating Water Column (OWC) concept, commonly investigated as wave energy converter (Falcão, 2010), can also represent a viable alternative to absorb the incident energy thus decreasing its reflection. However, the studies that investigate its effectiveness as anti-reflection device are quite limited (Liu and Geng, 2012, He and Huang 2016). This work aims to contribute to the present knowledge on the effectiveness of an OWC, embodied in quay walls or harbor breakwaters, as an alternative to reduce the wave reflection at vertical wall structures.

Comparison of the performance of oscillating water column devices based on arrangements of water columns

2020 ◽  
Vol 14 (3) ◽  
pp. 7082-7093
Author(s):  
Jahirwan Ut Jasron ◽  
Sudjito Soeparmani ◽  
Lilis Yuliati ◽  
Djarot B. Darmadi
Keyword(s):  
Wave Propagation ◽  
Water Column ◽  
Water Depth ◽  
Graphical Form ◽  
Wave Power ◽  
Oscillating Water Column ◽  
Power Absorption ◽  
Water Columns ◽  
Single Column ◽  
Parallel Arrangement

The hydrodynamic performance of oscillating water column (OWC) depends on the depth of the water, the size of the water column and its arrangement, which affects the oscillation of the water surface in the column. An experimental method was conducted by testing 4 water depths with wave periods of 1-3 s. All data recorded by the sensor is then processed and presented in graphical form. The research focused on analyzing the difference in wave power absorption capabilities of the three geometric types of OWC based on arrangements of water columns. The OWC devices designed as single water column, the double water column in a series arrangement which was perpendicular to the direction of wave propagation, and double water column in which the arrangement of columns was parallel to the direction of wave propagation. This paper discussed several factors affecting the amount of power absorbed by the device. The factors are the ratio of water depth in its relation to wavelength (kh) and the inlet openings ratio (c/h) of the devices. The test results show that if the water depth increases in the range of kh 0.7 to 0.9, then the performance of the double chamber oscillating water column (DCOWC) device is better than the single chamber oscillating water column (SCOWC) device with maximum efficiency for the parallel arrangement 22,4%, series arrangement 20.8% and single column 20.7%. However, when referring to c/h, the maximum energy absorption efficiency for a single column is 27.7%, double column series arrangement is 23.2%, and double column parallel arrangement is 29.5%. Based on the results of the analysis, DCOWC devices in parallel arrangement showed the ability to absorb better wave power in a broader range of wave frequencies. The best wave of power absorption in the three testing models occurred in the wave period T = 1.3 seconds.

Experimental study on the motions of a dual chamber floating oscillating water column device

2021 ◽  
Vol 170 ◽  
pp. 1257-1274 ◽  
Author(s):  
J.F.M. Gadelho ◽  
K. Rezanejad ◽  
S. Xu ◽  
M. Hinostroza ◽  
C. Guedes Soares
Keyword(s):  
Experimental Study ◽  
Water Column ◽  
Oscillating Water Column ◽  
Dual Chamber

Interaction of oblique waves with an Oscillating Water Column device

2021 ◽  
Vol 228 ◽  
pp. 108931
Author(s):  
Ayrton Alfonso Medina Rodríguez ◽  
Alejandro Martínez Flores ◽  
Jesús María Blanco Ilzarbe ◽  
Rodolfo Silva Casarín
Keyword(s):  
Water Column ◽  
Oscillating Water Column ◽  
Oblique Waves
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