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![| Vertical wall attached with (a) a plain parapet in Kailua-Kona, Hawaii, USA (Source: [Online] Available at http://www.drhank.com/ kona/ [Accessed 07 February 2022]) and (b) a recurved parapet in Cornwall, United Kingdom.](publication/363553028/figure/fig1/AS:11431281084488434@1663220051479/Vertical-wall-attached-with-a-a-plain-parapet-in-Kailua-Kona-Hawaii-USA-Source.png)
| Vertical wall attached with (a) a plain parapet in Kailua-Kona, Hawaii, USA (Source: [Online] Available at http://www.drhank.com/ kona/ [Accessed 07 February 2022]) and (b) a recurved parapet in Cornwall, United Kingdom.
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Experiments are the traditional techniques used in coastal engineering to study complex wave structure interactions. However, with the advent of high-performance computing, even performing 1:1 scale numerical simulations has become a reality. The progress aids in extending the parametric investigation or repeating the procedure for comparable struc...
Contexts in source publication
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... parapet is an attachment placed on top of the vertical seawall as a retrofitting element in order to mitigate wave overtopping characteristics over the structure. Different types of parapets, such as plain ) and recurved ( Ravindar et al. 2018Ravindar et al. , 2019Stagonas et al. 2020), as shown in Figure 1, are employed and categorised based on different combinations of overhang length, exit angle, and curvature. When attached to a vertical seawall, a parapet reduces wave overtopping by deflecting the uprushing water in the seaward direction with their exit angle. ...
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... wave elevation and amplitude spectrum are compared between numerical and experimental results in Figure 10 for the H07T4 test case. The wave elevation at locations 160 m (η i ) and 235 m from wavemaker (η toe ) (i.e. ...
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... the entire physical phenomenon is captured in the domain, which is considered for the simulation. Figure 10 shows the wave elevation before the slope (η i ) and near the structure (η toe ). ...
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... the pressure transducers fixed to the vertical wall and the recurved part of the structure, the critical pressure transducer comparison at the impact zone (PT1-PT4) on the vertical wall and uprushing zone (PT11-PT16) on the parapet are shown in Figures 11 and 12. The impact pressures from sensors 1 to 4 are found to be matching with typical impact pressure from literature, i.e. significant dynamic impact pressure and secondary quasi-static pressure were noticed. ...
Context 5
... the wave reaches the curved geometry, due to the high momentum from the wave than the gravity, the dynamic pressure would be predominant, and the contact duration during the rising time will be high than during impact. This was exactly noticed in pressure sensors 11-16, as shown in Figure 12. ...
Context 6
... the current situation, significant impact pressure is detected in both the vertical and recurve parts of the wall. This example was identified in test case 5 (H07T6BrL), and wave-breaking patterns on the structure are illustrated in Figure 13. Figure 14 shows the wave elevation before the slope (η i ) and near the structure (η toe ) for the H07T6 test case. ...
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... example was identified in test case 5 (H07T6BrL), and wave-breaking patterns on the structure are illustrated in Figure 13. Figure 14 shows the wave elevation before the slope (η i ) and near the structure (η toe ) for the H07T6 test case. For wave elevation before the slope (η i ) in Figure 14, the overall profile matches well, but in the initial three wave peaks, slight reflection is observed in troughs of experiment results. ...
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... example was identified in test case 5 (H07T6BrL), and wave-breaking patterns on the structure are illustrated in Figure 13. Figure 14 shows the wave elevation before the slope (η i ) and near the structure (η toe ) for the H07T6 test case. For wave elevation before the slope (η i ) in Figure 14, the overall profile matches well, but in the initial three wave peaks, slight reflection is observed in troughs of experiment results. This is later self-corrected by the active absorption with the increase in wave height during upcoming wave peaks. ...
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... is later self-corrected by the active absorption with the increase in wave height during upcoming wave peaks. Considering wave elevation near the structure (η toe ) in Figure 14, the experimental and numerical results compare well, capturing the reflected and incident part. This is further verified by the amplitude spectrum at the incident and near the structure location. ...
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... Figure 15, it can be observed that the wave profile has small aeration, due to which one could notice an oscillatory nature of pressure in sensors 1 and 2, but these minor oscillations are not captured in the numerical model. Furthermore, the secondary quasi-static impact pressure is not dominant when compared to SBW on the vertical wall, as noticed in sensors 1-4. ...
Context 11
... is consistent with observations by Chan and Melville ( Kisacik et al. 2012) indicated with respect to the turbulent bore by Goda & Haranaka (1967) and by Oumeraci et al. (1993). The double peak observed may be due to the split-up of entrapped air into bubbles in the free surface that deflect through the boundary of the recurve with splashes, as shown in Figure 16. ...
Context 12
... impact pressure is seen in both the vertical and recurve parts. This was found in our test case 6 (H07T8BrL), as seen in Figure 17. Figure 18 shows the wave elevation before the slope (η i ) and near the structure (η toe ) for the H07T8 test case. ...
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... was found in our test case 6 (H07T8BrL), as seen in Figure 17. Figure 18 shows the wave elevation before the slope (η i ) and near the structure (η toe ) for the H07T8 test case. The influence of the reflected wave is not observed in numerical results, and this can also be observed in wave elevation at incident location (η i ) as shown in Figure 11, where the reflection part in troughs of experimental results is not observed in numerical results. ...
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... was found in our test case 6 (H07T8BrL), as seen in Figure 17. Figure 18 shows the wave elevation before the slope (η i ) and near the structure (η toe ) for the H07T8 test case. The influence of the reflected wave is not observed in numerical results, and this can also be observed in wave elevation at incident location (η i ) as shown in Figure 11, where the reflection part in troughs of experimental results is not observed in numerical results. The elevation disparities between computational and experimental results in troughs might be attributed to complex 3D effects in wave breaking wherein turbulence is important, which is obviously a shortcoming of the 2D model utilised in ...
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... effect is found in waves with higher wave periods. However, after stabilisation, the numerical wave tank reciprocates the wave profile, which is clearly seen in wave elevation near the structure (η toe ) in Figure 18. The small variations are unavoidable due to the breaking and reflections in the experiments considering these complex phenomena. ...
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... maximum impact pressure on the vertical part is found to occur at sensor 2, as shown in Figure 19. One could easily observe the oscillations in the pressure measurements indicating the larger aeration ( Bullock et al. 2007). ...
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... wave elevation is compared between numerical and experimental results in Figures 10, 14, and 18. The comparison is shown for three prominent breaking cases, SBW corresponding to the test case H07T4, BWSAT corresponding to the test case H07T6 and BWLAT corresponding to the test case H07T8. ...
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... efficacy of the numerical model in recreating the incident wave circumstances and reflection characteristics near the structure from the experiments is examined in this section. Figure 21 shows the ratio of energy between experiment and numerical results at incident and toe location. The energy ratio is obtained from the amplitude spectrum from figures by calculating the area under the curve. ...
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... on Figure 21, at the incident location, the numerical simulations are efficient in recreating similar incident wave conditions and the error percentage ranges from 1 to 7%. These error percentages are independent of test parameters and recurved parapet type. ...
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... location of entrapped air for the BWSAT breaking case is found at z/d ¼ 0.965 (ref. Figure 13), and for the BWLAT case is lowered to z/d ¼ 0.885 (ref. Figure 17), which is quantitatively shown in Figure 28 discussing the vertical distribution of impact pressure for different parapets. ...
Context 21
... 13), and for the BWLAT case is lowered to z/d ¼ 0.885 (ref. Figure 17), which is quantitatively shown in Figure 28 discussing the vertical distribution of impact pressure for different parapets. Furthermore, the amount of air entrained due to breaking waves is also different. ...
Context 22
... fall-off time determines the interaction between the incoming and deflected water which in turn leads to a change in pressure distribution. As the incoming waves are altered due to interference, each parapet type's respective impact pressure generated is altered, as shown in Figures 31-33. Figures 31-33 show mean pressure (average of all the pressure peaks pertaining to a location) comparison between recurved parapet, plain parapet and vertical wall for large (BrL), medium (BrM) and small (BrS) cases. ...
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