Control of Short-period and Solitary Waves Using Two-rowed Impermeable Rectangular Submerged Dike

2열 불투과성 사각형 잠제를 이용한 단주기파랑 및 고립파의 제어

  • Lee, Kwang-Ho (Department of Civil Engineering, School of Engineering, Nagoya University) ;
  • Jung, Sung-Ho (Department of Civil Engineering, Korea Maritime University) ;
  • Ha, Sun-Wook (Department of Civil Engineering, Korea Maritime University) ;
  • Kim, Do-Sam (Department of Civil Engineering, Korea Maritime University)
  • 이광호 ((일)나고야대학교 공학연구과 사회기반공학) ;
  • 정성호 (한국해양대학교 토목공학과) ;
  • 하선욱 (한국해양대학교 토목공학과) ;
  • 김도삼 (한국해양대학교 토목공학과)
  • Received : 2010.01.28
  • Accepted : 2010.07.26
  • Published : 2010.08.31

Abstract

This study numerically investigates the wave control of 2-rowed Impermeable Rectangular Submerged Dike(IRSD) with an object of how to control short-period and solitary waves simultaneously based on the Bragg resonance phenomenon that elevates the wave control performance. The boundary integral method using Green formula and the 3-D one-field Model for immiscible TWO-Phase flows (TWOPM-3D) by 3-D numerical wave flume have been used for the numerical predictions for short-period and solitary waves, respectively. These numerical models were verified through the comparisons with the previously published numerical results by other researchers. Through the parametric tests of numerical experiments for short-period waves, an optimum model of 2-rowed IRSD of a lowest transmission coefficient has been found. Furthermore, the performances of 3-D wave control for solitary waves were evaluated for the various free board, crown widths and gap distance between dikes, and have been compared with those of a single-rowed IRSD. Numerical results show that a 2-rowed IRSD with a less cross sectional area than 1-rowed one improves the wave attenuation performances when it is compared to that of single-rowed IRSD. Within the test frequency ranges of the numerical simulations conducted in this study, 2-rowed IRSD with an optimum gap distance shows an outstanding improvement of the wave attenuation up to 58% compared to that of single-rowed IRSD.

본 연구에서는 단주기파랑과 고립파를 동시에 저감시키기 위해 Bragg공진현상으로부터 입사파랑에너지를 포획하여 배후로 전달되는 파랑에너지의 저감을 도모할 수 있는 2열 불투과성 사각형 잠제(이하에서는 2열잠제로 칭함)의 파랑제어능을 수치적으로 검토하였다. 단주기파랑에 대해서는 Green공식에 기초한 경계적분방정식법을, 고립파에 대해서는 3차원수치파동수로를 이용하는 3차원혼상류해석법을 각각 적용하였고, 기존의 수치해석결과 및 고립파의 특성과 비교·분석하여 본 수치해석법의 타당성을 검증하였다. 이로부터 단주기파랑의 제어에 있어서 최소반사율을 나타내는 2열잠제의 조건을 검토하였고, 고립파에 대해서는 2열잠제의 천단고, 천단폭, 이격거리 및 입사파고 등을 변화시켜 1열 불투과성 사각형 잠제(이하에서는 1열잠제로 칭함)에 의한 결과와의 대비를 통하여 고립파의 3차원파랑제어특성을 검토하였다. 수치해석결과는 1열잠제보다 단면적이 훨씬 적은(천단고는 동일함) 2열잠제가 단주기파랑 및 고립파를 훨씬 효율적으로 제어하며, 특히 본 연구의 조건하에서 2열잠제의 경우가 1열잠제에 비해 약 58%정도의 부가적인 파고저감효과를 나타내었다.

Keywords

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