KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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Numerical Analysis for Bed Changes at the Meandering Stream due to a Short Term Flood Event

단기 홍수사상으로 인한 사행하천의 하상변동 수치모의 분석

  • Ji, Un (Korea Institute of Civil Engineering and Building Technology) ;
  • Jang, Eun Kyung (Korea Institute of Civil Engineering and Building Technology) ;
  • Lee, Chan Joo (Korea Institute of Civil Engineering and Building Technology)
  • 지운 (한국건설기술연구원 수자원.하천연구소, 과학기술연합대학원대학교 건설환경공학과) ;
  • 장은경 (한국건설기술연구원 수자원.하천연구소) ;
  • 이찬주 (한국건설기술연구원 수자원.하천연구소)
  • Received : 2015.06.10
  • Accepted : 2015.10.16
  • Published : 2015.12.01
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Abstract

In this study, flow characteristics and bed changes during a short term flood event were analyzed using the two-dimensional CCHE2D model for a meandering sand-bed river, the Naesung Stream. Flow and bed change simulation was carried along the three sub-reaches with sinuosity of 1.2, 1.6 and 2.2 for the 6-day flood event occurring in June 2011. The simulation results indicated that velocity variation due to flow concentration was larger along the sub-reach with the sinuosity less than 1.5 and bed erosion at the outside of the bend was increased by time. In the sub-reach with the sinuosity less than 1.5, the maximum flood discharge produced the maximum flow velocity over 1.6 m/s to 2 m/s locally.

본 연구에서는 다양한 사행도를 갖는 내성천 하도 구간에 대해 단기 홍수사상 발생시 나타나는 흐름과 하상변동 특성을 2차원 모형인 CCHE2D를 이용하여 분석하였다. 내성천 하도 구간은 사행도가 1.2, 1.6, 2.2인 3개 구간으로 나누어 흐름 및 하상변동 모의를 수행하였으며, 2011년 6월에 발생한 6일 동안의 홍수사상에 대해 모의를 수행하였다. 모의 결과, 사행도가 큰 구간에 비해 사행도가 1.5 미만인 구간에서 흐름 집중현상에 의한 평면적 유속차가 크게 나타났으며, 만곡부에서의 하상침식이 시간에 따라 더 크게 확대된 것을 알 수 있었다. 사행도가 1.5 미만인 구간에서는 최대홍수량이 발생했을 때 최대유속이 국부적으로 1.6 m/s에서 2 m/s 이상인 것으로 나타났다.

Keywords

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