KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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Experimental Study of Vegetated Flows in the Stream-scale Natural Channel

자연형 수로 내 식생흐름 분석을 위한 실험적 연구

  • Ryu, Yong-Uk (Pukyong National University) ;
  • Kim, Jihyun (Korea Institute of Civil Engineering and Building Technology) ;
  • Ji, Un (Korea Institute of Civil Engineering and Building Technology) ;
  • Kang, Joongu (Korea Institute of Civil Engineering and Building Technology)
  • 류용욱 (부경대학교 해양공학과) ;
  • 김지현 (한국건설기술연구원 국토보전연구본부) ;
  • 지운 (한국건설기술연구원 국토보전연구본부) ;
  • 강준구 (한국건설기술연구원 국토보전연구본부)
  • Received : 2019.08.09
  • Accepted : 2019.08.29
  • Published : 2019.10.01
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Abstract

This study experimentally investigated the effects of high and low densities of vegetation patches on the flow characteristics in a stream-scale outdoor experimental channel with rooted willows. Stream-scale experiments on vegetated flows were carried out for an emergent condition of vegetation. Vegetation patches were arranged by alternate bar formation and the flows in vegetated and non-vegetated sections were compared. Three-dimensional flow structure was measured by ADV (Acoustic Doppler Velocimeter) and the vertical distributions of longitudinal velocity were mainly analyzed from the measurements at various points. Flow velocities show different patterns depending on the density of vegetation patches. The difference in flow velocity between in the vegetated and non-vegetated sections appear to large in the dense patches and the flow becomes complicated at the downstream edge of the patch. Despite the upstream flow disturbed by the first patch, the flows over the second patch show the similar pattern.

하천 내 흐름에 대한 식생 밀도의 영향을 조사하기 위해 버드나무가 활착된 하천 규모의 자연형 수로에서 유동 측정 실험을 수행하였다. 식생 내 흐름에 대한 하천 규모 실험은 식생의 반 잠김 조건에 대해 수행되었다. 수로 내 식생대(vegetation patch)는 교차로 형성된 사주의 형상으로 배열되었고 식생 구간과 비식생 구간에서의 흐름을 비교하였다. 3차원 유동 구조는 초음파 유속계(Acoustic Doppler Velocimeter)에 의해 측정되었고 종방향 속도의 연직 분포는 다양한 지점에서의 측정값으로부터 분석되었다. 유속은 식생대의 밀도에 따라 다른 양상을 보여 주는데, 식생 구간와 비식생 구간에서의 흐름 속도의 차이는 밀집된 식생대 주변에서 크게 나타나며 흐름 분포의 형태는 식생대의 하류방향 하단에서 복잡한 모습을 나타낸다. 하류에 위치한 식생대 주변의 흐름은 상류에 설치된 식생대에 의해 교란된 흐름에도 불구하고 유사한 분포를 보여준다.

Keywords

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