Journal of Korea Water Resources Association (한국수자원학회논문집)

Korea Water Resources Association (한국수자원학회)
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Applicability of hiding-exposure effect to suspension simulation of fine sand bed

가는 모래의 부유 모의시 차폐효과 고려의 영향

  • Byun, Jisun (Research Center for Smart Infra Construction, Chungnam National University) ;
  • Son, Minwoo (Department of Civil Engineering, Chungnam National University)
  • 변지선 (충남대학교 스마트인프라건설연구소) ;
  • 손민우 (충남대학교 공과대학 토목공학과)
  • Received : 2021.04.21
  • Accepted : 2021.06.16
  • Published : 2021.08.31
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Abstract

The purpose of this study is to simulate the transport of nonuniform sediment considering the hiding-exposure effect numerically. In order to calculate the transport of multi-disperse suspended sediment mixtures, the set of advection-diffusion equations for each particle class is solved. The applicability of the numerical model is examined by comparing the simulation results with experimental data. In this study, we calculate the vertical distribution of total concentration of sediment particles using two approaches: (1) by considering the mixture as represented by a single size; and (2) by combining the concentration of the sediment corresponding to several particle size classes; From the simulation results, it is shown that both approaches calculate reasonable results due to the narrow range of size distribution. Under the condition of nonuniform sediment, the critical shear stress of the sediment particle is influenced by the size-selective entrainment, i.e., hiding-exposure effect. It is shown in this study that the effect of hiding-exposure effect on the erosion rates of fine sand is negligibly small.

본 연구는 가는 모래로 이루어진 하상으로부터 침식된 부유사의 농도분포 계산결과에 차폐효과가 미치는 영향을 살펴보는 것을 목적으로 수행되었다. 하상재료의 입도분포를 고려하여 침식율을 산정할 수 있는 유사이동 모형을 개발하였으며, 측정자료와의 비교를 통해 수치모형의 적용가능성을 검토하였다. 수치모의결과로부터 하상재료 입도분포의 기하표준편차가 1.5보다 작은 경우 차폐효과가 부유사 농도의 연직방향 분포 계산결과에 미치는 영향은 매우 작은 것으로 나타났다. 또한 기하표준편차가 1.5이하인 가는 모래로 이루어진 하상으로부터 침식된 유사 농도를 계산하는 경우, 균일사로 가정 후 대표입경을 바탕으로 농도를 산정하여도 합리적인 결과가 얻어지는 것으로 확인되었다.

Keywords

Acknowledgement

본 연구는 2021년도 한국연구재단 창의도전(No. NRF-2020R1I1A1A01055310)의 지원을 받아 수행되었습니다.

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