Journal of Korea Water Resources Association (한국수자원학회논문집)

Korea Water Resources Association (한국수자원학회)
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One-Dimensional Model for Flow Resistance of Floodplain Vegetation in Compound Open-Channel Flow

복단면 개수로흐름에서 홍수터 식생의 흐름저항을 반영한 1차원 모형

  • Park, Moon-Hyeong (River, Coastal and Harbor Research Division, Korea Institute of Construction Technology)
  • 박문형 (한국건설기술연구원 하천. 해안항만연구실)
  • Received : 2010.04.07
  • Accepted : 2010.04.14
  • Published : 2010.06.30
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Abstract

In this study, the 1D apparent shear stress model for vegetated compound open-channel flows was suggested. To consider the effect of momentum exchange between main channel and floodplain, the eddy viscosity concept was used in the present model. The interfacial eddy viscosity in the interface of main channel and floodplain was determined from the 3D Reynolds stress model. The evaluated interfacial eddy viscosity appears to be good agreement with those proposed previously. To investigate the effect of interfacial eddy viscosity, sensitive analysis was carried out. the computed backwater profiles are nearly identical with respect to the value of the interfacial eddy viscosity. However, the discharge conveyed by the floodplain changes is proportional to the interfacial eddy viscosity. Finally, the changes of the interfacial eddy viscosity due to the vegetation density and vegetation height were examined. The computed results of interfacial eddy viscosity are in proportion to the vegetation density and vegetation height, and the interfacial eddy viscosity has a range of $(2-5)\;{\times}\;10^{-4}$.

본 연구에서는 식생이 포설된 홍수터를 포함하는 복단면 개수로 흐름의 수위를 예측하기 위하여 유효 전단응력기법에 근거한 일차원 모형을 제시하였다. 제안된 모형은 주수로와 홍수터 접합부에서 발생하는 운동량 교환효과를 와점성계수 개념을 이용하여 반영할 수 있다. 주수로와 홍수터의 경계에서 발생하는 경계와점성계수는 3차원 레이놀즈 응력 모형을 이용하여 결정하였다. 경계와점성계수의 영향을 파악하기 위하여 민감도분석을 수행하였다. 경계와점성계수의 변화에 대하여 배수곡선의 변화는 크지 않았으나, 홍수터에서 부담하는 유량은 경계와점성계수에 비례하여 증가하였다. 마지막으로 식생된 홍수터의 식생밀도 및 침수비에 따른 경계와점성계수의 변화를 살펴보았다. 계산된 경계와점성계수는 식생밀도와 침수비에 비례하며, 대략$(2-5){\times}\;10^{-4}$ 정도의 값을 갖는 것으로 나타났다.

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References

  1. Bousmar, D., and Zech, Y. (1999). “Momentum transfer for practical flow computation in compound channels.” Journal of Hydraulic Engineering, ASCE, Vol. 125, No. 7, pp. 696-706. https://doi.org/10.1061/(ASCE)0733-9429(1999)125:7(696)
  2. Cunge, J.A., Holly, F.M. Jr., Verwey, A. (1980). Practical Aspects of Computational River Hydraulics, Pitman Publishing Ltd., London, UK.
  3. Dunn, C.J. (1996). “Experimental determination of drag coefficients in an open-channel with simulated vegetation.” Master thesis, Department of Civil Engineering, University of Illinoisat Urbana-Champaign, Urbana, IL.
  4. Ervine, D. A., and Baird, J.I. (1982). “Rating curves for rivers with overbank flow.” Proc., I.C.E., Part II, London, Vol. 73, pp. 465-472.
  5. Helmio, T. (2002). “Unsteady 1D flow model of compound channel with vegetated floodplains.” Journal of Hydrology, Vol. 269, pp. 89-99. https://doi.org/10.1016/S0022-1694(02)00197-X
  6. Kang, H., and Choi, S.-U. (2005). “3D numerical simulation of compound open-channel flow with vegetated floodplains by Reynolds stress model.” KSCE Journal of Civil Engineering, Vol. 9, No. 1, pp. 7-11. https://doi.org/10.1007/BF02829092
  7. Kang, H. (2004). “Reynolds stress modeling of vegetated open-channel flows.” Ph.D. Thesis, Department. of Civil Engineering, Yonsei University, Seoul, Korea.
  8. Knight, D.W., and Hamed, M.E. (1984). “Boundary shear in symmetrical compound channel.” Journal of the Hydraulics Division, ASCE, Vol. 110, No. 10, pp. 1412-1430. https://doi.org/10.1061/(ASCE)0733-9429(1984)110:10(1412)
  9. Myers, R.C., Lyness, J.F. (1997). “Discharge ratios in smooth and rough compound channels.” Journal of Hydraulic Engineering, ASCE, Vol. 123, No. 3, pp. 182-188. https://doi.org/10.1061/(ASCE)0733-9429(1997)123:3(182)
  10. Nepf, H.M. (1999). “Drag, turbulence, and diffusion in flow through emergent vegetation.”Water Resources Research, AGU, Vol. 35, No. 2, pp. 479-489. https://doi.org/10.1029/1998WR900069
  11. Sellin, R.H.J. (1964). “A laboratory investigation into the interaction between the flow in the channel of a river and that over its floodplains.” La Houille Blanche, Vol. 7, pp. 793-802.
  12. Wormleaton, P.R., Allen, J., and Hadjipanos, P. (1982). “Discharge assessment in compound channel flow.” Journal of the Hydraulics Division, ASCE, Vol. 108, No. 9, pp. 975-994.
  13. Wormleaton, P.R., and Merrett, D.J. (1990). “An improved method of the calculation for steady uniform flow in prismatic main channel/floodplain sections.” Journal of Hydraulic Research., IAHR, Vol. 28, No. 2, pp. 157-174.
  14. Yen, B.C. (1984). “Hydraulic of floodplains: Methodology for backwater computation.” Institute of Hydraulic Engineering Reports No. 84/5(HWV053), University of Stuttgart, Germany.
  15. Yen, B.C., Camacho, R., Kohane, R., and Westrich, B. (1985). “Significance of floodplain in backwater computation.” Proceeding of the 21st IAHR Congress, Melbourne, Australia, Vol. 3, pp. 439-445.
  16. Yen, C.L., and Overton, D.E. (1973). “Shape effects on resistance in flood-plain channels.” Journal of the Hydraulic Division, ASCE, Vol. 99, No. HY1, pp. 219-238.

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