Laboratory Investigation on Wave Reflection Characteristics of Suspended Perforated Pipe Breakwater

Abstract

A laboratory investigation on the suspended perforated hollow cylinders in a single row was conducted in a two-dimensional wave flume, to study their hydraulic performance. The influence of depth of submergence, size of pipes, percentage of perforations and water depth on wave reflection characteristics have been investigated. From the investigation it was found that, as the relative depth of submergence increases, reflection increases. Water depth has insignificant effect on reflection coefficient K, The reflection coefficient K, increases as incident wave steepness increases. For perforated pipes, size of the pipe has negligible effect on K,. Wave period alone does not directly influence the reflection.

Investigation on innovative pile head breakwater for coastal protection

“…It is also evident from the investigation that up to 12.4% reduction in K t could be achieved by incorporating the perforations on the surface of conical pile head breakwater. The obtained outcome is well matching with the literature 4,25,26,58 where, 10% to 14% lesser K t is reported through perforations.…”

“…Further, the perforation characteristics such as distribution, percentage and size of perforations which play a significant role in the energy dissipation, are identified, and their ranges are selected based on the literature review. 4,25,26 The calculation of the distribution of perforations (Pa) on the surface of CPH is illustrated in Figure 6. The wave climate (wave height and period) chosen is in accordance with the data obtained off the Mangaluru coast, west coast of India.…”

“…Perforated hollow pile breakwater consists of an array of perforated hollow cylindrical piles where the piles have uniform diameter throughout the length, as shown in Figure 1(d). 25 The wave attenuation characteristics of the perforated hollow pile breakwater are estimated based on the theoretical approach as there are no data available in the literature corresponding to the structural configuration and test limit of the present study. Therefore, the hybrid equations developed by Suvarna et al 42 for perforated hollow pile breakwater is adopted to extract the data.…”

“…The perforations were expected to increase the wave-structure interaction resulting in higher energy dissipation. Rao and Rao 25,26 investigated the influence of perforations on the transmission and reflection characteristics of the suspended perforated pipe breakwater (Refer Figure 1(e)) by providing the pores on the suspended pipe breakwater. The perforated pipes with 25% of perforations were found to be effective in enhancing wave attenuation by about 10% to 14% with lesser reflection than the similar non-perforated structure.…”

“…) conducted on pile type of breakwaters. The results of optimum configured perforated CPHB (D/H max = 0.4, Y/H max = 1.5, b/D = 0.1, Pa = 50%, P = 19.2%, S/D = 0.25 and h = 0.45 m) is compared with the perforated hollow pile breakwater,25 suspended perforated pipe breakwater,26 …”