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2019 Vol.52, Issue 4 Preview Page

Research Article

Wall-roughness effects of trapezoidal ribs on the flow of open channel

개수로 흐름에서 사다리꼴 돌출줄눈의 벽면조도 효과

Seung Sook Shina
,
Sang Deog Parkb*
,
Ho Kook Parkc
신 승숙a
,
박 상덕b*
,
박 호국c
aResearch Professor, Research Center for River Flow Impingement and Debris Flow, Gangneung-Wonju National University
bProfessor, Department of Civil Engineering, Gangneung-Wonju National University
cMaster Course, Department of Civil Engineering, Gangneung-Wonju National University
a강릉원주대학교 수충부및토석류방재기술연구단 연구교수
b강릉원주대학교 토목공학과 교수
c강릉원주대학교 토목공학과 석사과정
* Corresponding Author
30 April 2019. pp. 255-264
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Abstract

The trapezoidal ribs had been installed in the retaining wall in order to reduce to flood damage in the impingement of mountain rivers. In this study, experiments in open channel with the trapezoidal ribs on sidewall were conducted to evaluate the effect of flow resistance by the trapezoidal shape. The hydraulic flow characteristics according to the flow rates were surveyed where the wall roughness is k-type that dimensionless spacings, λnv, are 6, 9, and 12. The flow-resistance factors such as roughness and friction coefficients increased generally with increase of the spacing of ribs. In high flow rate the friction coefficient showed the maximum value when λnv is 9. Though the trapezoidal ribs has the relatively smaller flow resistance compared to the square ribs, their form drag accounted for mean 62% of the total flow resistance. It was confirmed that the optimal spacing of trapezoidal ribs to maximize the effect of flow resistance as the wall roughness increases are 9 to 12 times of the height of trapezoidal ribs.

Keywords
Trapezoidal rib
Spacing of ribs
Flow resistance
Wall roughness

산지하천 만곡부의 홍수피해를 줄이고자 사다리꼴 단면의 돌출줄눈을 하천옹벽에 설치하였다. 본 연구에서는 사다리꼴 형상에 의한 흐름저항 효과를 파악하고자 개수로 측벽에 사다리꼴 돌출줄눈을 설치하여 수리실험을 수행하였다. 벽면조도가 k형에 해당하는 λnv가 6, 9, 12인 경우에 대해 유량에 따른 흐름특성을 파악하였다. 흐름저항은 돌줄줄눈의 설치간격이 멀어짐에 따라 전반적으로 증가하였다. 고유량 조건에서 최대마찰계수는 λnv가 9일 때 발생하였다. 사다리꼴 돌출줄눈은 정사각형 돌출줄눈과 비교해 흐름저항은 상대적으로 작았지만, 사다리꼴의 형상저항은 전체 흐름저항의 평균 62%를 차지했다. 벽면조도 증가에 따른 흐름저항 효과를 극대화하기 위한 사다리꼴 돌출줄눈의 최적 설치간격은 돌출줄눈 높이의 9∼12배 범위임을 확인하였다.

키워드
사다리꼴 돌출줄눈
돌출줄눈 간격
흐름저항
벽면조도
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Information
  • Publisher :KOREA WATER RESOURECES ASSOCIATION
  • Publisher(Ko) :한국수자원학회
  • Journal Title :Journal of Korea Water Resources Association
  • Journal Title(Ko) :한국수자원학회 논문집
  • Volume : 52
  • No :4
  • Pages :255-264
  • Received Date : 2018-12-27
  • Revised Date : 2019-02-18
  • Accepted Date : 2019-03-08
  • DOI :https://doi.org/10.3741/JKWRA.2019.52.4.255
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