Effects of Wave Dissipation with Circular Cylinders

J. Ocean Eng. Technol. 2008;22(4):27-33.

Lee Seong-Dae,Kim Seong-Deuk

Dept. of Civil Engineering Halla Univ.,Dept. of Civil and Environmental Eng. University of Ulsan

원형파일군에 의한 파랑제어 특성

이성대,김성득

한라대학교 토목공학과,울산대학교 건설환경공학부

Keywords: Vertical cylinders, Wave dissipation, Unsteady mild slope equation, Opening Ratio, Numerical model, Hydraulic experiment

핵심용어: 원형파일군, 파랑감쇠, 비정상완경사방정식, 개구율, 수치모형, 수리실험

Abstract

One of the central problems in astudy of the coastal surface wave environment is predicting the transformation of waves as they propagate toward the shore. The transformation is mainly due to the existence of obstacles, such as breakwaters and vertical cylinders. In general, the types of wave transformation can be classified as follows: wave diffraction, reflection, transmission, scattering, radiation, et al. This research dealtwith wave transmission and dissipation problems for two dimensional irregular waves and vertical circular cylinders. Using the unsteady mild slope equation, a numerical model was developed to calculate the reflection and transmission of regular waves from a multiple-row circular breakwater and vertical cylinders. In addition, hydraulic model experiments were conducted with different values for the properties between tire piles and the opening ratio (distances) between the rows of the breakwater. It was found that the transmission coefficients decreased with a decrease in the opening ratio and an increase in the rows of vertical cylinders. A comparison between the results of hydraulic and numerical experiments showed reasonable agreement.