Wave pressure acting on V-shaped floating breakwater in random seas

Abstract

Wave pressure on the wet surface of a V-shaped floating breakwater in random seas is investigated. Considering the diffraction effect, the unit velocity potential caused by the single regular waves around the breakwater is solved using the finite-depth Green function and boundary element method, in which the Green function is solved by integral method. The Response-Amplitude Operator (RAO) of wave pressure is acquired according to the Longuet-Higgins' wave model and the linear Bernoulli equation. Furthermore, the wave pressure's response spectrum is calculated according to the wave spectrum by discretizing the frequency domain. The wave pressure's characteristic value corresponding to certain cumulative probability is determined according to the Rayleigh distribution of wave heights. The numerical results and field test results are compared, which indicates that the wave pressure calculated in random seas agrees with that of field measurements. It is found that the bigger angle between legs will cause the bigger pressure response, while the increase in leg length does not influence the pressure significantly. The pressure at the side of head sea is larger than that of back waves. When the incident wave angle changes from 0˚ to 90˚, the pressure at the side of back waves decreases clearly, while at the side of head sea, the situation is more complicated and there seems no obvious tendency. The concentration of wave energy around low frequency (long wavelength) will induce bigger wave pressure, and more attention should be paid to this situation for the structure safety.

Hydrodynamic Efficiency of a Wave Energy Converter in Front of an Orthogonal Breakwater

“…Pressure hydrodynamic coefficients of the OWC in the i-th direction, due to the unit air pressure inside the n device, n = 1, 2, PTO damping coefficient c 33 Hydrostatic stiffness coefficient P(ω) Wave power absorbed by the WEC…”

“…Several different types of patents offering different types of V-shaped breakwaters have been presented in the last decades [26,27], whereas in May 1999 the U.S. Army Engineer Research and Development Center designed a novel concept of floating breakwaters composed of two arms in a "V-shape" to promote the stability of vessel loading/offloading activities [28,29]. Pioneering works on the wave effects on V-shaped breakwaters are [30][31][32][33]. Concerning the investigations on the behavior of WECs placed in front of V-shaped breakwaters, theoretical and experimental studies were developed in [34,35], whereas the effect of a sea-bottom fixed orthogonal breakwater on the hydrodynamics of bottom seated or floating cylindrical bodies has been studied in [36][37][38].…”