• Title/Summary/Keyword: 투과성 해저지반

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Applicability of Permeable Submerged Breakwater for Discharged Flow Control (방류 흐름제어를 위한 투과성 잠제의 적용성 분석)

  • Hur, Dong-Soo;Lee, Woo-Dong
    • Journal of Korea Water Resources Association
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    • v.49 no.1
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    • pp.51-60
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    • 2016
  • The purpose of this study is to examine the control function of discharged flow due to the shape and plane arrangement of permeable submerged breakwater. For the discussion on it in detail, 3-dimensional numerical model based on PBM (Porous Body Model), which is able to simulate directly interaction of Fluid Permeable structure Seabed has been used to simulate water discharge in a NWT (Numerical Water Tank). To verify the applicability, LES-WASS-3D is analyzed comparing to the experimental result about propagation characteristics of dam-break wave through a permeable structure. Using the results obtained from numerical simulation, the effects of the shape and plane arrangement of submerged breakwater on reducing velocity and flow induction have been discussed related to the mean flow distribution and vertical distributions of horizontal velocities around ones.

On Damping of Irregular Waves Passing over a Permeable Seabeds (해저투수층을 통과하는 불규칙파의 파랑감쇠에 관한 연구)

  • Hur, Dong-Soo;Choi, Dong-Seok;Lee, Woo-Dong;Bae, Ki-Seong
    • Journal of Ocean Engineering and Technology
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    • v.21 no.6
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    • pp.34-41
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    • 2007
  • The present study investigates numerically damping characteristics of irregular waves passing over a permeable seabeds. At first, the numerical model, which is able to consider the flow through a porous medium with inertial, laminar and turbulent resistance terms and determine the eddy viscosity with LES turbulent model, is validated by comparing with existing experimental data. And then, the numerical test on irregular wave damping over a permeable seabeds is performed in case that wave and flume conditions are changed. It is revealed from the numerical results that the more porosity and mean grain are increased, the more wave damping is increased. Also, the effect of wave period on damping of irregular waves over a permeable seabed is discussed.

An Analytical Solution of Dynamic Responses for Seabed under Flow and Standing Wave Coexisting Fields (흐름과 완전중복파와의 공존장하에서 해저지반내 동적응답의 해석해)

  • Lee, Kwang-Ho;Kim, Dong-Wook;Kim, Do-Sam;Kim, Tae-Hyung;Kim, Kyu-Han;Jeon, Jong-Hyeok
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.27 no.2
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    • pp.118-134
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    • 2015
  • An analytical solution of dynamic responses for seabed in shallow, finite and infinite thicknesses has been developed under flow and standing wave coexisting field at a constant water depth condition. To do this, based on the Biot's consolidation theory, the seabed is assumed as a porous elastic media with the assumptions that pore fluid is compressible and Darcy law governs the flow. The developed analytical solution is compared with the previous results and is verified. Using the analytical solution the deformation, pore pressure, effective and shear stresses of seabed are examined under various given values of flow velocity, incident wave period and seabed thickness. From this study, it is confirmed that the seabed response is quite different depending on consideration of flow, which causes changing period and length of incident and reflection waves.

On Reasonable Boundary Condition for Inclined Seabed/Structure in Case of the Numerical Model with Quadrilateral Mesh System (사각격자체계 수치모델에서의 경사면 처리기법에 관하여)

  • Hur, Dong-Soo;Lee, Woo-Dong;Bae, Ki-Seong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.5B
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    • pp.591-594
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    • 2008
  • Present study aims at the development of a reasonable boundary condition for a structure over inclined seabed in case of the numerical model with quadrilateral mesh system. The technique for the inclined impermeable/permeable boundary in the quadrilateral mesh is newly proposed. The new technique and LES-WASS-3D model (Hur and Lee, 2007) have been used for the investigation of the dynamics of fluid field, and validated through the comparison with a typical stair-type boundary condition. 3-Dimensional numerical model with Large Eddy Simulation is called LES-WASS-3D, and is able to simulate directly interaction of WAve Structure Sea bed/Sandy beach.

Development of Numerical Model for Scour Analysis under Wave Loads in Front of an Impermeable Submerged Breakwater (불투과 잠제 전면에서 파랑 작용 하의 세굴 해석을 위한 수치모델의 개발)

  • Hur, Dong-Soo;Jeon, Ho-Seong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.5B
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    • pp.483-489
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    • 2011
  • In this study, the coupled-numerical model has been newly developed to investigate numerically scouring and deposition around a coastal structure like a submerged breakwater using a numerical wave model and a lagrangian particle model for sand transport. As a numerical wave model, LES-WASS-2D (Hur and Choi, 2008) is adopted. The model is able to consider the flow through a porous midium with inertial, laminar and turbulent resistance term and determine the eddy viscosity with LES turbulence model. Distinct element method (Cundall and Strack, 1979), which is able to apply to many dynamical analysis of particulate media, as a lagrangian particle model for sand transport is newly coupled to the numerical wave model. The numerical simulation has been carried out to examine the scour problem in front of an impermeable submerged breakwater using the newly coupled-numerical model. The numerical results has been compared qualitatively with an existing experimental data and then its applicability has been discussed.

An Analytical Solution of Dynamic Responses for Seabed under Coexisting Fields of Flow and Partial Standing Wave with Arbitrary Reflection Ratio (흐름과 임의반사율을 갖는 부분중복파와의 공존장하에서 해저지반내 동적응답의 해석해)

  • Lee, Kwang-Ho;Kim, Dong-Wook;Kang, Gi-Chun;Kim, Do-Sam;Kim, Tae-Hyung;Na, Seung-Min
    • Journal of the Korean Geotechnical Society
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    • v.31 no.6
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    • pp.27-44
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    • 2015
  • An analytical solution of dynamic responses for seabed in finite and infinite thicknesses including shallow has been developed under flow and partial standing wave with arbitrary reflection ration coexisting field at a constant water depth condition. In the analytical solution, a field was simply transited to a coexisting field of progressive wave and flow when reflection ratio was 0 and to a coexisting field of fully standing wave and flow when reflection ratio was 1. Based on the Biot's consolidation theory, the seabed was assumed as a porous elastic media with the assumptions that pore fluid is compressible and Darcy law governs the flow. The developed analytical solution was compared with the existing results and was verified. Using the analytical solution the deformation, pore pressure, effective and shear stresses were examined under various given values of reflection ratio, flow velocity, incident wave's period and seabed thickness. From this study, it was confirmed that the dynamic response of seabed was quite different depending on consideration of flow, which causes changing period and length of incident and reflection waves. It was also confirmed that dynamic response significantly depends on the magnitude of reflection ratio.

A Study on Beach Stabilization by Laying Drainage Layer (투수층 매설에 의한 해빈안정화에 관한 연구)

  • Hur, Dong-Soo;Lee, Woo-Dong;Jeon, Ho-Sung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.3B
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    • pp.325-335
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    • 2010
  • The aim of this study is to survey the effects of laying drainage layer in sandy beach on beach stabilization. At first, the numerical model developed by Hur and Lee (2007), which is able to consider the flow through a porous medium with inertia, laminar and turbulent resistance terms, i.e. simulate directly WAve Structure Seabed/Sandy beach interaction and can determine the eddy viscosity with LES turbulent model in 3-D wave field (LES-WASS-3D), is validated by comparing with existing experimental data. And then, numerical simulation is carried out to examine the characteristics of wave-sandy beach interaction for a beach with/without drainage layer. From the numerical results, it is shown that mean ground-water level around a foreshore decreases and offshore-ward flow over a seabed reduces in case of a beach with drainage layer. Moreover, the effects of cross profile of drainage layer and incident wave condition on mean ground-water level around a foreshore are also discussed as well the distribution of wave setup around the foreshore.