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1 September 2013 The Natural Ocean Engineering Laboratory, NOEL, in Reggio Calabria, Italy: A Commentary and Announcement
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Abstract

Arena, F. and Barbaro, G., 2013. The Natural Ocean Engineering Laboratory, NOEL, in Reggio Calabria, Italy: A commentary and announcement.

The Natural Ocean Engineering Laboratory (NOEL) of the Mediterranea University of Reggio Calabria, Italy, is the first ocean engineering laboratory working in the field. A peculiarity of the lab is that a local wind from NNW often generates sea states consisting of pure wind waves that represent a small scale model, in Froude similarity, of ocean storms. Significant wave height ranges between 0.20 m and 0.80 m, with peak periods between 2.0 s and 3.6 s. This local wind is very stable and sometimes stays steady from morning to evening. The tidal amplitude is very small (typically within 0.10 m). The physical structure was built after the successful experience of some initial small-scale field experiments directed by Professor Paolo Boccotti since 1989.

INTRODUCTION

At the Natural Ocean Engineering Laboratory (NOEL) it is possible to operate in the sea with the same techniques used in laboratories with wave tanks. The facility is located on the promenade of Reggio Calabria (Italy), where a wind from NNW blows many days per week, generating waves with significant wave height within 0.20 m < Hs < 0.80 m and a peak period within 2.0 s < Tp < 3.6 s. The wave spectra are very close to the JONSWAP spectra (Hasselmann et al., 1973), confirming the occurrence of wind wave sea states. At the NOEL, we may work with 1:30 small-scale models of strong Mediterranean storms or with 1:50 scale models of oceanic storms, approximately.

The NOEL is a field laboratory, due to a combination of some exceptional conditions:

  1. the high stability of the local wind, blowing from Messina toward Reggio Calabria for many consecutive days,

  2. the orientation of the coast (see Figure 1), which is protected from the swells that propagate in the Strait of Messina from the south,

  3. the small tide amplitude and the clean water due to the passage twice a day of the Strait current.

The concept of the laboratory began in 1989, when Professor Paolo Boccotti directed the first experiment designed to verify the possibility of operating directly at sea. In the experiment, the mechanics of three-dimensional wave groups in the open sea and the occurrence of exceptionally high waves were analyzed by verifying his quasi-determinism theory. After three more experiments, the Mediterranea University of Reggio Calabria decided to build a laboratory on the promenade of the Reggio Calabria city.

The Mediterranea University of Reggio Calabria has direct management of the laboratory. The experimental activities are run by the research group coordinated by Professor Paolo Boccotti (Scientific Supervisor) and Professor Felice Arena (Director of the Lab), with the support of Giuseppe Barbaro (Associate Professor), Vincenzo Fiamma (Assistant Professor), and Alessandra Romolo (Assistant Professor). PhD students from the ocean engineering program, as well as post-doctoral and graduate students, participate in the experiments. In the laboratory, academic activities, such as lectures for undergraduate students, are also held.

LABORATORY AND EXPERIMENTAL ACTIVITY

The laboratory has its own beach, with an area of about 4500 m2, and its own water sheet within 50 m from the shoreline. The structure has a surface area of 350 m2 and includes a conference room, a room with the electronic station, a PC network, and offices (Figure 2).

The small-scale field experiments are performed in the water sheet off the beach. The instruments are connected by cables to the electronic station, and the people who attend a symposia can get a real-time view of the experiments.

The first series of experiments was set up to verify the quasi-determinism theory, both in the open sea and in front of a vertical seawall (Experiment RC-1990, 1991) (Boccotti, 1997, 2008; Boccotti, Barbaro, and Mannino, 1993; Boccotti et al., 1993). After the success of these initial experiments, some further small-scale field experiments concerning the interaction of ocean waves with a gravity offshore platform (Experiment RC-1992) (Boccotti, 1995), a large horizontal cylinder (Experiment RC-1993) ( Arena, 2002, 2006; Boccotti, 1996), and again with a vertical seawall (Experiment RC-1994) were carried out at NOEL (Boccotti, 2000). Since 2001, a new kind of caisson for the production of electrical power from ocean waves was conceived and then tested in the laboratory. It consists of an oscillating water column device with a particular geometry that enables reaching a resonant condition between the plant and the incident waves without any mechanical devices (Experiment RC-2001, 2005) (Figures 3a and b). The new plant is named REWEC (Resonant Wave Energy Converter), and it could be designed to reach the resonant condition under the waves conveying the greatest amount of wave energy at the fixed location. Two small-scale field experiments were carried out: in 2001 on the submerged caisson REWEC1 (REWEC - Realization 1), which also can work for the protection of the coast (Arena and Filianoti, 2007; Boccotti, 2003), and in 2005 on the vertical breakwater REWEC3 (REWEC - Realization 3), which also can work as a harbor structure (Boccotti, 2007a, b; Boccotti, 2012a; Boccotti et al., 2007).

Some important results were found from the experiment on REWEC3 in 2005. The theoretical model developed by Boccotti for the REWEC device was validated, showing the plant can convert up to 100% of the incident wave energy associated to swells, due to a super amplification of these swells before the plant. In a large number of the swells records, nearly 100% of the wave energy was absorbed. Moreover, the behavior of the device under wind waves was confirmed.

Some coastal investigations have been made by Barbaro and Foti (2013) concerning the evolution of the shoreline behind a seawall, by Barbaro, Foti, and Malara (2011) concerning the set-up, and by Barbaro (2011) concerning extreme events.

In 2009, with the new management of the NOEL, many small-scale field experiments were carried out. In 2009, the experiment NOEL 1 studied the directional spectrum recorded by wave gauges, either ultrasonic probes measuring the free surface elevation or transducers measuring the wave pressure (Figure 4). During the experiment, the directional spreading of wave groups was measured to obtain a new method to achieve directional spectra (Boccotti et al., 2011).

In the same year three other experiments were conducted: NOEL2, NOEL3, NOEL4. The experiments NOEL2 and NOEL4 dealt with the wave pressures and wave forces acting on vertical walls at sea. These experiments were carried out at different relative water depths. The wave force was measured by means of a set of pressure transducers on the mid-vertical section of the wall, and the results are given in Boccotti et al. (2012a) and Romolo and Arena (2008, 2013) (Figure 5).

The experiment NOEL4 analyzed the wave forces on cylinders (Barbaro, 2007; Barbaro, Ierinó, and Martino, 2007; Romolo et al., 2009). The experiment was performed by considering a vertical cylinder. The wave force was measured by a set of pressure transducers in a horizontal section of the cylinder (Figure 6). A detailed description of these experiments was made by Boccotti et al. (2012b).

In 2010, two other important experiments were performed. The first one, NOEL5, was concerned with the space-time evolution of three-dimensional wave groups (Boccotti, 2011a). Boccotti's quasi-determinism theory predicts that the high waves during storms are joined in groups, and all wave groups with high waves have the same characteristics and have similar changing during their propagation. During this experiment, 26 wave gauges were used for recording waves simultaneously. The result is a full and spectacular validation of the quasi-determination theory. It was found that various wave groups reconded on different days are very close to each other when a very high wave occurs (very high with respect to the mean wave height). A very important consequence in engineering is that freak waves (or giant waves) during a storm have all the same characteristics and have the same evolution during their propagation.

The second experiment of 2010, NOEL6, was concerned with hydrodynamic forces of sea waves on horizontal submerged cylinders. The free surface displacement was recorded by two ultrasonic probes (Figure 7a); the forces on the cylinder were recorded by eight pressure transducers (Figure 7b). It is the first experiment on sea wave forces on submerged pipelines that was carried out at sea with laboratory techniques (Boccotti et al., 2013).

During 2011 the wave mechanics in front of a vertical breakwater were investigated (Boccotti, 2013), and in 2012 the wave group mechanics and statistics in space-time domain were investigated (Boccotti, 2011b, 2012b).

The last experiment, performed in 2013, investigated wave forces on upright breakwaters in shallow water. This experiment provided the opportunity to investigate the effect of breaking waves on the upright breakwater (Arena, Barbaro, and Romolo, 2013; Arena et al., 2013; Barbaro and Martino, 2007), and the results are still being processed (Figure 8). An important consequence of the experiment was to verify the possibility to operate the NOEL for coastal engineering. Information on activities in the NOEL may be found in the website  www.noel.unirc.it.

LITERATURE CITED

1.

F Arena 2002. Statistics of wave forces on large horizontal cylinders, Ocean Engineering, 29(4), 359–372. Google Scholar

2.

F Arena 2006. Interaction between long-crested random waves and a submerged horizontal cylinder. Physics of Fluids, 18, 076602. Google Scholar

3.

F Arena G Barbaroand A Romolo 2013. Return period of a sea storm with at least two waves higher than a fixed threshold. Mathematical Problems in Engineering, 2013, 1–6. Google Scholar

4.

F Arenaand P Filianoti 2007. A small-scale field experiment on a submerged breakwater for absorbing wave energy. Journal of Waterway, Port, Coastal, and Ocean Engineering, 133(2), 161–167. doi: 10.1061/(ASCE)0733-950X(2007)133:2(161Google Scholar

5.

F Arena G Malara G Barbaro A Romoloand S Ghiretti 2013. Long term modelling of wave run-up and overtopping during sea storms. Journal of Coastal Research, 29(2), 419–429. Google Scholar

6.

G Barbaro 2007. A new expression for the direct calculation of the maximum wave force on vertical cylinders. Ocean Engineering, 34(11–12), 1706–1710. doi: 10.1016/j.oceaneng.2006.10.013 Google Scholar

7.

G Barbaro 2011. Estimating design wave for offshore structures in italian waters. Proceedings of the Institution of Civil Engineers: Maritime Engineering, 164(3), 115–125. Google Scholar

8.

G Barbaroand G Foti 2013. Shoreline behind a break water: comparison between theoretical models and field measurements for the Reggio Calabria sea. Journal of Coastal Research, 29(1), 216–224. Google Scholar

9.

G Barbaro G Fotiand G Malara 2011. Set-up due to random waves: influence of the directional spectrum. In: Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering.–Volume 6 (Rotterdam, The Netherlands, ASME), pp. 789–797. Google Scholar

10.

G Barbaro B Ierinóand M.C Martino 2007. Maximum force produced by wind generated waves on offshore maritime structure. In: Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering (New York, ASME), pp. 1–8. Google Scholar

11.

G Barbaroand M.C Martino 2007. On the run-up levels and relative mean persistence. In: Proceedings International Offshore and Polar Engineering Conference (California, USA), vol. 3, pp. 1816–1821. Google Scholar

12.

P Boccotti 1995. A field experiment on the small scale model of a gravity offshore platform. Ocean Engineering, 22(6), 615–627. Google Scholar

13.

P Boccotti 1996. Inertial wave loads on horizontal cylinders: a field experiment. Ocean Engineering, 23(7), 629–648. Google Scholar

14.

P Boccotti 1997. A general theory of three-dimensional wave groups. Ocean Engineering, 24(3), 265–300. Google Scholar

15.

P Boccotti 2000. Wave Mechanics for Ocean Engineering. New York: Elsevier Science, p. Google Scholar

16.

P Boccotti 2003. On a new wave energy absorber. Ocean Engineering, 30(9), 1191–1200. Google Scholar

17.

P Boccotti 2007a. Comparison between a U-OWC and a conventional OWC. Ocean Engineering, 34(5–6), 799–805. doi: 10.1016/j.oceaneng.2006.04.005 Google Scholar

18.

P Boccotti 2007b. Caisson breakwaters embodying an OWC with a small opening—part I: theory. Ocean Engineering, 34(5–6), 806–819.. doi: 10.1016/j.oceaneng.2006.04.006 Google Scholar

19.

P Boccotti 2008. Quasi-determinism theory of sea waves. Journal Offshore Mechanics and Arctic Engineering, 130(4), pp. 1–9. Google Scholar

20.

P Boccotti 2011a. Field verification of quasi-determinism theory for wind waves in the space–time domain. Ocean Engineering, 38(13), 1503–1507. doi: 10.1016/j.oceaneng.2011.07.015 Google Scholar

21.

P Boccotti 2011b. A field experiment on the recurrence of large waves in wind seas. Open Journal of Marine Science, 3, 69–72. doi: 10.4236/ojms.2011.13007 Google Scholar

22.

P Boccotti 2012a. Design of breakwater for conversion of wave energy into electrical energy. Ocean Engineering, 51, 106–118. doi: http://dx.doi.org/10.1016/j.oceaneng.2012.05.011 Google Scholar

23.

P Boccotti 2012b. A new property of distributions of the heights of wind-generated waves. Ocean Engineering, 54, 110–118. doi:  http://dx.doi.org/10.1016/j.oceaneng.2012.06.015 Google Scholar

24.

P Boccotti 2013. Field verification of quasi-determinism theory for wind waves interacting with a vertical breakwater. Journal of Waterway, Port, Coastal, Ocean Engineering, doi: 10.1061/(ASCE)WW.1943–5460.0000198Google Scholar

25.

P Boccotti F Arena V Fiamma A Romoloand G Barbaro 2011. Estimation of mean spectral directions in random seas. Ocean Engineering, 38(2–3), 509–518. doi: 10.1016/j.oceaneng.2010.11.018 Google Scholar

26.

P Boccotti F Arena V Fiamma A Romoloand G Barbaro 2012a. Small-scale field experiment on wave forces on upright breakwaters. Journal of Waterway, Port, Coastal, and Ocean Engineering, 138(2), 97–114. doi: 10.1061/ (ASCE)WW.1943–5460.0000111 Google Scholar

27.

P Boccotti F Arena V Fiammaand G Barbaro 2012b. Field experiment on random-wave forces on vertical cylinders. Probabilistic Engineering Mechanics, 28, 39–51. doi: 10.1016/j.probengmech.2011.08.003 Google Scholar

28.

P Boccotti F Arena V Fiammaand A Romolo 2013. Two small-scale field experiments on the effectiveness of Morison's equation. Ocean Engineering, 57, 141–149. doi:  http://dx.doi.org/10.1016/j.oceaneng.2012.08.011 Google Scholar

29.

P Boccotti G Barbaroand L Mannino 1993. A field experiment on the mechanics of irregular gravity waves. Journal of Fluid Mechanics, 252, 173–186. Google Scholar

30.

P Boccotti G Barbaro L Mannino V Fiammaand A Rotta 1993. An experiment at sea on the reflection of the wind waves. Ocean Engineering, 20(5), 493–507. Google Scholar

31.

P Boccotti P Filianoti V Fiammaand F Arena 2007. Caisson breakwaters embodying an OWC with a small opening–part II: a small-scale field experiment. Ocean Engineering, 34(5–6), 820–841. doi: 10.1016/j.oceaneng.2006.04.016 Google Scholar

32.

K Hasselmann T.P Barnett E Bouws H Carlson D.E Cartwright K Eake J.A Euring A Gicnapp D.E Hasselmann P Kruseman A Meerburg P Mullen D.J Olbers K Richren W Selland H Walden 1973. Measurements of wind wave growth and swell decay during the Joint North Sea Wave Project (JONSWAP). Erga¨nzungsheft zur Deutschen Hydrographischen Zeitschrift, A8, 1–95. Google Scholar

33.

A Romolo F Arena 2008. Mechanics of nonlinear random wave groups interacting with a vertical wall”, Phys. of Fluids, 20, 036604/1–16, doi:  10.1063/1.2890474Google Scholar

34.

A Romolo F Arena 2013 Three-dimensional nonlinear standing wave groups: formal derivation and experimental verification, International Journal of Non-Linear Mechanics, in In press. Google Scholar

35.

A Romolo G Malara G Barbaroand F Arena 2009. An analytical approach for the calculation of random wave forces on submerged tunnels. Applied Ocean Research, 31(1), 31–36. doi: 10.1016/j.apor.2009.04.001Google Scholar

Figure 1. 

Laboratory location.

i1551-5036-29-5-vii-f01.tif

Figure 2. 

View of the NOEL laboratory, entrance, and conference room.

i1551-5036-29-5-vii-f02.tif

Figure 3. 

(a) The caisson utilized during the experiment RC-2001. (b) One of the nine modules constituting the absorbing breakwater of the experiment RC-2005.

i1551-5036-29-5-vii-f03.tif

Figure 4. 

Ultrasonic probes used during the NOEL1 experiment to measure the directional spectrum.

i1551-5036-29-5-vii-f04.tif

Figure 5. 

View of the caissons used in the NOEL2,4 experiments during a storm.

i1551-5036-29-5-vii-f05.tif

Figure 6. 

Sketch of the NOEL3 experiment.

i1551-5036-29-5-vii-f06.tif

Figure 7. 

(a) Ultrasonic probes used to measure the water surface elevation. (b) Sketch of the horizontal cylinder used during the NOEL6 experiment.

i1551-5036-29-5-vii-f07.tif

Figure 8. 

View of the vertical breakwater in shallow water used in the 2013 experiment.

i1551-5036-29-5-vii-f08.tif
F. Arena and G. Barbaro "The Natural Ocean Engineering Laboratory, NOEL, in Reggio Calabria, Italy: A Commentary and Announcement," Journal of Coastal Research 29(5), (1 September 2013). https://doi.org/10.2112/13A-00004
Received: 24 June 2013; Accepted: 27 June 2013; Published: 1 September 2013
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