Journal of Korea Water Resources Association (한국수자원학회논문집)

Korea Water Resources Association (한국수자원학회)
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Water wave reflection over shear currents and dredged multi-arrayed trenches

외부 흐름과 준설된 다열 함몰지형에 의한 파랑의 반사

  • Cho, Yong-Sik (Department of Civil and Environmental Engineering, Hanyang University) ;
  • Lee, Kwang-Jun (Department of Civil and Environmental Engineering, Hanyang University) ;
  • Lee, Jun-Whan (Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University)
  • 조용식 (한양대학교 공과대학 건설환경공학과) ;
  • 이광준 (한양대학교 대학원 건설환경공학과) ;
  • 이준환 (버지니아 폴리테크닉 주립 대학교 건설환경공학과)
  • Received : 2020.07.20
  • Accepted : 2020.09.01
  • Published : 2020.10.31
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Abstract

Understanding the wave characteristics near the outlet of coastal power plants for cooling water in the vicinity of the dredged areas is critically important for the construction and operation of the plants. By Employing the eigenfunction expansion method, in this study, we analyzed the reflection of monochromatic water waves over (1) shear currents near the outlet and (2) multi-arrayed trenches representing dredged areas. We firstly optimized the number of grids expressing shear currents and the number of evanescent modes based on a convergence test. We then analyzed the sensitivity of the reflection coefficients depending on (1) magnitude of shear currents, (2) width of shear currents, (3) a distance between adjacent trenches, and (4) a number of trenches. The results showed that the reflection coefficient was more sensitive to the number of trenches and the distance between trenches than the velocity of shear currents and the width of shear currents. We also found that even the effect of shear currents is relatively small, the effect is not negligible in a relative water depth from shallow to near shallow water waves (0.01 < kh ≦ 0.70).

임해발전소의 냉각수 배출구 인근과 준설된 해역을 전파하는 파랑의 특성을 이해하는 것은 임해발전소 건설과 운영에 매우 중요하다. 본 연구에서는 (1) 배출구 주변 외부 흐름과 (2) 준설된 해저지형을 나타내는 함몰지형에 의한 파랑의 반사율을 고유함수전개법을 이용하여 해석하였다. 먼저, 외부흐름을 나타내기 위한 격자수와 소멸파수의 최적값을 수렴 테스트를 통해 산정하였다. 그리고 1)외부흐름의 속도, 2)외부흐름의 폭, 3)함몰지형 간 거리, 4)함몰지형의 개수에 따른 반사율 변화 정도를 분석하였다. 분석결과, 함몰지형 수와 거리에 따른 반사율이 외부흐름의 속도와 폭에 따른 반사율보다 더 민감한 결과를 보였다. 또한, 외부흐름의 영향이 작을지라도 천해와 천해부근 상대수심 (0.01 < kh ≦ 0.70)에서는 외부흐름의 영향을 무시할 수 없다는 것을 확인하였다.

Keywords

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