Journal of Korean Society of Coastal and Ocean Engineers (한국해안·해양공학회논문집)

Korean Society of Coastal and Ocean Engineers (한국해안·해양공학회)
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Estimation of Entrainment Rate of Fluid Mud using Annular Flume

환형수조를 이용한 머드유동층의 연행부상률 산정

  • Kim, Dong-Ho (Dept. of Civil Eng. & Research Institute for Disaster Prevention, Chonbuk National Univ.) ;
  • Kim, Won-Kyu (Dept. of Civil Eng., Chonbuk National Univ.) ;
  • Hwang, Kyu-Nam (Dept. of Civil Eng. & Research Institute for Disaster Prevention, Chonbuk National Univ.)
  • 김동호 (전북대학교 토목공학과, 방재연구센터) ;
  • 김원규 (전북대학교 토목공학과) ;
  • 황규남 (전북대학교 토목공학과, 방재연구센터)
  • Received : 2016.08.16
  • Accepted : 2016.10.11
  • Published : 2016.10.31
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Abstract

In this study, experiments for measurements of entrainment rate of fluid mud were carried out using annular flume domestically for the first time. Six entrainment tests using kaolinite sediments were conducted with different initial concentrations of fluid mud. It is shown that sediment settling counteracts the otherwise buoyancy dependent entrainment of fluid mud, and that the settling effect leads to a measurably decreased entrainment rate at higher Richardson numbers in comparison with entrainment of salt water, due to additional dissipation of turbulent kinetic energy in the interfacial layer. Through the comparison with previous other studies, the overall performance of the annular flume, the experimental procedure and the test results in simulating the entrainment of fluid mud are shown to be good enough to verify.

본 연구에서는 머드유동층의 연행부상률 산정을 목적으로 국내 최초로 환형수조를 이용하여 고령토 머드유동층에 대한 연행부상 실험이 수행되었다. 고령토로 제작된 머드유동층의 초기농도를 변화시키면서 총 6회의 연행부상 실험이 수행되었으며, 머드유동층의 연행부상률이 정량적으로 산정되었다. 본 연구결과에 따르면, 머드유동층의 부상률과 반대방향으로 작용하는 토사의 침강의 영향으로 인하여, 경계면에서 난류 운동에너지의 부가 손실이 유발되고, 결과적으로 리차드슨 수가 높은 경우에 염수 성층 구조일 때 보다 상당히 감소된 부상률이 초래되는 것으로 나타났다. 또한, 과거 타 연구결과와의 비교 검토를 통하여 본 연구에서 사용된 환형수조는 성능 상에 문제가 없음이 간접적으로 확인되었으며, 연행부상 실험 방법 및 실험 결과의 타당성이 입증되었다.

Keywords

References

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