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2025 Vol.26, Issue 9
Wave Scattering at the Offshore Structure with Partial Reflecting Boundary Using Polynomial Approximation

다항식 근사해법을 이용한 부분 반사율을 갖는 해상구조물에서의 파랑의 산란에 관한 연구

Jinhyeaok Jang1
,
Hojin Lee2*
,
Sungduk Kim3
장 진혁1
,
이 호진2*
,
김 성덕3
1PhD Candidate, School of Civil Engineering, Chungbuk National University
2Professor, School of Civil Engineering, Chungbuk National University
3Instructor, School of Civil Engineering, Chungbuk National University
*Corresponding Author
1 September 2025. pp. 5-12
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Abstract

This study investigated the wave field around a breakwater when a coastal structure with partial reflectivity is installed in the sea area. The basic theory is to compare and analyze the scattered waves in the area behind the breakwater by applying the Fresnel integral and polynomial approximation method. Afterwards, it was compared and analyzed the numerical results of the boundary element method and the polynomial approximation method, which are numerical solution methods based on boundary integral equations. The offshore structure was analyzed for its length ratio to wavelength and the scattering coefficient according to the change in the incident angle of the wave. The Fresnel integral and polynomial approximation solutions gave perfect agreement in the calculation results when the wave was incident in both the normal and oblique directions. The polynomial approximation and numerical solutions were almost in agreement except for a slight difference behind the breakwater. When using a numerical solution, the calculation time was reduced by about 30% compared to when using the Fresnel integral. The results of this study can present the influence of scattering caused by each structure when placing breakwaters and offshore structures during port construction, and can provide information on setting specifications for breakwater design and interaction with surrounding waters.

Keywords
Polynomial approximation
Wave scattering
Boundary element method(BEM)
Breakwater
port

본 연구는 부분 반사율을 갖는 해상 구조물이 해역에 설치될 때 방파제에 기인한 주변의 파랑장을 조사한 것이다. 기본적인 이론은 프레넬 적분과 다항식 근사해법을 적용하여 방파제 배후 영역에서의 산란파에 대하여 비교·분석을 하였다. 이후 다항식 근사해법과 경계적분방정식을 기본으로 하는 수치해법인 경계요소법의 수치결과와도 비교·분석하였다. 해상 구조물은 도제 형태로서 파장에 대한 길이비와 파랑의 입사각도 변화에 따른 산란계수를 분석하였다. 파랑이 법선방향 및 경사진 방향으로 입사할 때 모두에서 프레넬 적분과 다항식 근사해법이 계산 결과 값이 완벽히 일치하였다. 다항식 근사해법과 수치해의 경우 방파제 배후에서의 약간의 차이를 제외하고는 거의 일치하였다. 수치해법을 사용하는 경우에는 프레넬 적분을 사용한 경우보다 약 30%의 시간 감소 효과가 나타났다. 본 연구의 결과를 통해 항만 걸설 시 방파제 및 해상 구조물을 배치할 때 각각의 구조물로 인하여 발생되는 산란의 영향을 제시할 수 있으며, 방파제 설계에 대한 제원 설정과 주변해역과의 상호작용에 대한 정보를 제공할 수 있다.

키워드
다항식 근사치
파의 산란
경계 요소법
방파제
항만
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Information
  • Publisher :Korean Geo-Environmental Society
  • Publisher(Ko) :한국지반환경공학회
  • Journal Title :Journal of the Korean Geo-Environmental Society
  • Journal Title(Ko) :한국지반환경공학회 논문집
  • Volume : 26
  • No :9
  • Pages :5-12
  • Received Date : 2025-06-20
  • Revised Date : 2025-06-25
  • Accepted Date : 2025-07-09
  • DOI :https://doi.org/10.14481/jkges.2025.26.9.5
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