Journal of Korea Water Resources Association (한국수자원학회논문집)

Korea Water Resources Association (한국수자원학회)
권호 표지
DOI QR코드

DOI QR Code

Numerical simulation of turbidity currents intruding into a reservoir

저수지로 유입되는 부유사 밀도류의 수치모의

  • Choi, Seongwook (Department of Civil & Environmental Engineering, Yonsei University) ;
  • Ban, Chaewoong (Department of Civil & Environmental Engineering, Yonsei University) ;
  • Choi, Sung-Uk (Department of Civil & Environmental Engineering, Yonsei University)
  • 최성욱 (연세대학교 대학원 토목환경공학과) ;
  • 반채웅 (연세대학교 대학원 토목환경공학과) ;
  • 최성욱 (연세대학교 공과대학 토목환경공학과)
  • Received : 2016.12.23
  • Accepted : 2017.03.03
  • Published : 2017.03.31
Download PDF
⟨ Previous Next ⟩

Abstract

This study proposes a numerical model which is able to simulate turbidity currents intruding into a reservoir and resulting sediment depositions. The proposed model is applied to laboratory experiments by Toniolo and Schultz (2005), and propagation of turbidity currents, morphological change, and trap of suspended sediment are simulated. It is simulated that the turbidity current after plunging at the foreset of the model delta, propagates along the bottom. The thickness of the turbidity current increases significantly after being blocked by the dam, and this effect is propagated in the upstream direction. In addition, it is simulated that the foreset moves in the downstream direction due to both the bedload and suspended load and the thickness of the bottom set increases due to the suspended load. It is found that the height of the intake affects the thickness of the turbidity current and the location of the internal hydraulic jump. The impact of the height of the intake on the trap efficiency is not clear in the experimental results, however, overall trap efficiency is predicted quite successfully by the model. Also, sensitivity analysis is carried out, and the results indicates that the particle size affects the trap efficiency most.

본 연구에서는 저수지에 유입된 부유사 밀도류에 의해 유사가 포집되는 현상을 모의하기 위한 수치모형을 제시하였다. 개발된 모형을 Toniolo and Schultz (2005)의 실내 실험에 적용하여, 부유사 밀도류의 전파, 하도형태의 변화, 그리고 댐에 의한 유사의 포집현상을 모의하였다. 삼각주의 전면층에서 침강된 밀도류가 빠르게 댐까지 전파된 후, 댐에 의해 차단되고 두께가 증가되어 상류로 영향을 전파하는 일련의 과정을 모의하였다. 또한, 소류사와 부유사에 의해 저수지 삼각주에서 전면층이 전진하고, 부유사에 의해 기저층의 두께가 상승하는 현상을 잘 모의하였다. 댐 취수구의 높이에 따른 밀도류의 최대 두께와 내부 도수 발생 위치를 확인하였다. 유사 포집 효율은 수치모형으로 실측 결과의 값을 적절히 모의하였으나, 실험의 한계로 인해 댐 취수구의 높이와 포집 효율과의 관계는 찾아볼 수 없었다. 수치모의 결과를 이용하여 유사 포집 효율의 민감도 분석을 수행한 결과 부유사의 입자 크기가 포집 효율에 가장 민감하게 작용하는 것을 확인할 수 있었다.

Keywords

References

  1. Brune, G. M. (1953). "Trap efficiency of reservoirs." Eos, Transactions American Geophysical Union, Vol. 34, No. 3, pp. 407-418. https://doi.org/10.1029/TR034i003p00407
  2. Brown, C. B. (1943). "Discussion of sedimentation in reservoirs." Proceeding of American Society of Civil Engineers, Vol. 69, No. 6, pp. 1493-1500.
  3. Choi, S., and Choi, S.-U. (2017). "A numerical simulation of propagating turbidity currents using the ULTIMATE scheme." Journal of Korea Water Resources Association, Vol. 49, No. 1, pp. 55-64.
  4. Choi, S.-U., and Garcia, M. H. (1995). "Modeling of one-dimensional turbidity currents with a dissipative-Galerkin finite element method." Journal of Hydraulic Research, Vol. 33, No. 5, pp. 623-648. https://doi.org/10.1080/00221689509498561
  5. Churchill, M. A. (1948). Discussion of "Analyses and use of reservoir sedimentation data" by L.C. Gottschalk. Proceedings of the Federal Inter-Agency Sedimentation Conference, Denver, Colorado, Washington, pp. 139-140.
  6. Crank, J. (1984). Free and moving boundary problems. Clarendon Press, Oxford, 425.
  7. Dietrich, E. W. (1982). "Settling velocities of natural particles." Water Resources Research, Vol. 18, No. 6, pp.1626-1682.
  8. Engelund, F., and Hansen, E. (1967). A Monograph on Sediment Transport in Alluvial Streams, Technisk Vorlag, Copenhagen, Denmark.
  9. Garcia, M., and Parker, G. (1989). "Experiments on hydraulic jumps in turbidity currents near a canyon-fan transition." Science, Vol. 245, No. 4916, pp. 393-396. https://doi.org/10.1126/science.245.4916.393
  10. Gill, M. A. (1979). "Sedimentation and useful life of reservoirs." Journal of Hydrology, Vol. 44, No. 1, pp. 89-95. https://doi.org/10.1016/0022-1694(79)90148-3
  11. Heinemarm, H. G. (1981). "A new sediment trap efficiency curve for small reservoirs 1." Journal of the American Water Resources Association, Vol. 17, No. 5, pp. 825-830. https://doi.org/10.1111/j.1752-1688.1981.tb01304.x
  12. Julien, P. Y. (2010). Erosion and sedimentation, Cambridge University Press, Cambridge, U.K., 371.
  13. Lewis, S. E., Bainbridge, Z. T., Kuhnert, P. M., Sherman, B. S., Henderson, B., Dougall, C., Cooper, M., and Brodie, J. E. (2013). "Calculating sediment trapping efficiencies for reservoirs in tropical settings: a case study from the Burdekin Falls Dam, NE Australia." Water Resources Research, Vol. 49, No. 2, pp. 1017-1029. https://doi.org/10.1002/wrcr.20117
  14. Morris, G. L., and Fan, J. (1997). Reservoir sedimentation handbook, McGraw-Hill, New York.
  15. Parker, G., Garcia, M., Fukushima, Y., and Yu, W. (1987). "Experiments on turbidity currents over an erodible bed." Journal of Hydraulic Research, Vol. 25, No. 1, pp. 123-147. https://doi.org/10.1080/00221688709499292
  16. Parker, G., and Toniolo, H. (2007). "Note on the analysis of plunging of density flows." Journal of Hydraulic Engineering, Vol. 133, No. 6, pp. 690-694. https://doi.org/10.1061/(ASCE)0733-9429(2007)133:6(690)
  17. Revel, N. M. T. K., Ranasiri, L. P. G. R., Rathnayake, R. M. C. R. K., and Pathirana, K. P. P. (2015). "Estimation of Sediment Trap Efficiency in Reservoirs-an Experimental Study." Engineer: Journal of the Institution of Engineers, Sri Lanka, Vol. 48, No. 2, pp. 43-49. https://doi.org/10.4038/engineer.v48i2.6833
  18. Siyam, A. M. (2000). Reservoir Sedimentation Control. Ph.D. Thesis, University of Bristol, England.
  19. Toniolo, H., and Schultz, J. (2005). "Experiments on sediment trap efficiency in reservoirs." Lakes and Reservoirs: Research and Management, Vol. 10, No. 1, pp. 13-24. https://doi.org/10.1111/j.1440-1770.2005.00256.x