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2025 Vol.58, Issue 8 Preview Page

Research Article

Large-scale experiment and 1D numerical modeling-based validation on estimation methods for flow resistance coefficient of vegetated floodplain

홍수터 식생의 흐름저항계수 추정방법에 대한 실규모 실험 및 1차원 수치모의 기반 검증

Un Jiab*
,
Sechan Parkc
,
Jiwon Ryud
지 운ab*
,
박 세찬c
,
류 지원d
aResearch Fellow, Department of Hydro Science and Engineering Research, Korea Institute of Civil Engineering and Building Technology, Goyang, Korea
bProfessor, Civil and Environmental Engineering, University of Science and Technology, Goyang, Korea
cUndergraduate Student, School of Spatial Environment System Engineering, Handong Global University, Pohang, Korea
dPh.D. Candidate, Civil and Environmental Engineering, University of Science and Technology, Goyang, Korea
a한국건설기술연구원 수자원하천연구본부 연구위원
b과학기술연합대학원대학교 건설환경공학 교수
c한동대학교 공간환경시스템공학부 학부생
d과학기술연합대학원대학교 건설환경공학 박사수료
*Corresponding Author
31 August 2025. pp. 681-692
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Abstract

This study analyzed the method of estimating the flow resistance coefficient for an asymmetric compound channel with a vegetative floodplain based on a large-scale experiment and one-dimensional numerical simulation. The accuracy of the one-dimensional numerical modeling prediction of the backwater profile according to the methods for calculating the flow resistance coefficient of the vegetated channel, such as the bulk and composite roughness coefficients, was evaluated. A relatively simple cylinder-type model-vegetation was applied to the floodplain, considering the complex phenomenon due to the influence of the channel geometry characteristics and the effect of the vegetation distributed in the floodplain. The bulk roughness coefficient was calculated from the measured data in the large-scale experiment. In the case of the composite roughness coefficient, the vegetated floodplain section along the cross-sectional wetted perimeter and the section without vegetation were divided and inputted to calculate the composite roughness coefficient in the one-dimensional backwater profile calculation. As a result of applying the bulk roughness coefficient, it was found that the agreement with the measured water levels was 98.2%. In the case of the composite roughness coefficient, the agreement between the predicted and the measured water levels varied from 42.3% to 98.3% depending on the drag coefficient input of the momentum-based flow resistance coefficient model for vegetative channels.

Keywords
Backwater profile calculation
Bulk roughness coefficient
Composite roughness coefficient
Large-scale experiment
Vegetative flow resistance coefficient

본 연구에서는 복단면 수로의 홍수터에 식생이 분포하는 경우 흐름저항계수 추정 방법에 대해 실규모 실험과 1차원 수치모의를 기반으로 분석하였다. 구간 조도계수 및 복합 조도계수와 같이 홍수터 식생의 흐름저항계수를 산정하는 방법에 따라 1차원 수치모델링의 수면곡선 예측 정확도를 평가하였다. 복단면 수로의 기하하적 단면 형태에 따른 영향과 홍수터에 분포하는 식생으로 인한 영향이 복합적으로 작용하는 것을 고려하여 홍수터 식생은 비교적 단순한 형태의 실린더 모형식생을 적용하였다. 구간 조도계수는 실규모 실험의 실측 결과를 기반으로 산정하였으며, 복합 조도계수의 경우 횡단면 윤변을 따라 식생이 분포하는 홍수터 구간과 식생이 없는 하도 구간을 구분하여 각각의 조도계수를 입력함으로써 1차원 수면곡선 계산에서 단면별 복합 조도계수가 산정되도록 하였다. 실규모 홍수터 식생 하도를 대상으로 구간 조도계수를 적용한 수면곡선 계산을 수행한 결과, 실측 수위와의 일치도가 98.2%인 것으로 나타났다. 복합 조도계수를 추정하는 방법의 경우 운동량 기반 식생 흐름저항계수 추정 모형의 항력계수 입력에 따라 1차원 수면곡선 계산 결과와 실측 수위의 일치도가 42.3%에서 98.3%까지 다양하게 나타났다.

키워드
수면곡선 계산
구간 조도계수
복합 조도계수
실규모 실험
식생 흐름저항계수
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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 : 58
  • No :8
  • Pages :681-692
  • Received Date : 2025-03-12
  • Revised Date : 2025-07-18
  • Accepted Date : 2025-07-23
  • DOI :https://doi.org/10.3741/JKWRA.2025.58.8.681
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