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Numerical simulation of dense interflow using the k-ε turbulence model

k-ε 난류모형을 이용한 중층 밀도류의 수치모의

Seongwook Choia
,
Seongwook Choia*
최 성욱a
,
최 성욱a*
aDepartment of Civil & Environmental Engineering, Yonsei University
a연세대학교 토목환경공학과
*교신저자. *Corresponding Author. 
30 September 2017. pp. 637-646
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Abstract

This study presents a numerical model for simulating dense interflows. The governing equations are provided and the finite difference method is used with the k-ε turbulence model. The model is used to simulate a dense interflow established in a deep ambient water, resulting velocity and excess density profiles. It is observed that velocity decreases in the longitudinal direction due to water entrainment in the vicinity of the outlet and rarely changes for increased Richardson number. Similarity collapses of velocity and excess density are obtained, but those of turbulent kinetic energy and dissipation rate are not. A shape factor for the dense interflow is obtained from the simulated profiles. The value of this shape factor can be used in the layer-averaged modeling of dense interflows. In addition, a buoyancy-related parameter ( ) for the k-ε model and the volume expansion coefficient () are obtained from the simulated results.

Keywords
Dense interflow
k-ε turbulence model
Layer-averaged model
Water entrainment
Buoyancy-related model parameter
Volume expansion coefficient

최근 기후변화에 효과적으로 대응하기 위해서 신뢰성 높은 설계홍수량을 산정할 필요성이 커지고 있다. 본 연구에서는 홍수빈도해석법과 설계 강우-유출 관계 분석법으로 산정되는 확률홍수량의 차이를 분석하였다. 우리나라의 경우 관측유량 자료가 부족하여 설계홍수량을 결정할 때 설계 강우-유출 관계 분석법으로 산정된 확률홍수량을 이용하고 있다. 관측 유량 자료를 활용한 홍수빈도해석법의 결과를 참값으로 가정하여 분석한 결 과, 설계강우-유출 관계 분석법으로 산정된 확률홍수량은 홍수빈도해석법으로 산정된 확률홍수량에 비해 약 79% 과대 산정되는 것으로 나타났 다. 따라서, 본 연구에서는 설계강우-유출 관계 분석법으로 산정된 확률홍수량을 보정하는 회귀곡선식을 개발하였다. 이를 위해 우리나라 8개 댐 유역의 강우와 유량자료를 획득한 후, 비선형 회귀분석을 통하여 보정식을 제안하였다. 본 연구에서 제안한 보정식을 적용할 경우, 설계강우-유출 관계 분석법으로 산정된 확률홍수량보다 평균적으로 정확도가 약 65.0% 향상되었다. 또한, 유역의 크기를 고려하면, 유역의 크기를 고려하지 않 았을 때보다 평균적으로 정확도가 약 2.1%p 증가하였다.

키워드
중층 밀도류
k-ε 난류모형
층적분 모형
물 연행
부력관련 모형상수
부피팽창계수
References
1
Altinakar, S., Graf, W. H., and Hopfinger, E. J. (1990). “Weakly depositing turbidity current on a small slope.” Journal of Hydraulic Research, Vol. 28, No. 1, pp. 55-80.
2
An, S., and Julien, P. Y. (2014). “Three-dimensional modeling of turbid density currents in Imha reservoir, South Korea.” Journal of Hydraulic Engineering, Vol. 140, No. 5, p. 05014004.
3
Britter, R. E., and Linden, P. F. (1980). “The motion of the front of gravity current travelling down an incline.” Journal of Fluid Mechanics, Vol. 99, pp. 531-543.
4
Cao, Z., Li, J., Pender, G., and Liu, Q. (2015). “Whole-process modeling of reservoir turbidity currents by a double layer- averaged model.” Journal of Hydraulic Engineering, Vol. 141, No. 2, p. 04014069.
5
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.
6
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.
7
Choi, S.-U., and Garcia, M. H. (2002). “Turbulence modeling of density currents developing two-dimensionally on a slope.” Journal of Hydraulic Engineering, Vol. 128, No. 1, pp. 55-63.
8
Chong, S.-A., Yi, H.-S., Lee, S.-Y., Lee, Y.-S., and Kim, D.-S. (2016). “Selecting the optimal location of debris containment booms in a reservoir using a ELCOM model.” Conference of Korea Water Resources Association 2016, p. 23.
9
Chung, S. W., Hipsey, M. R., and Imberger, J. (2009). “Modelling the propagation of turbid density inflows into a stratified lake: Daecheong reservoir, Korea.” Environmental Modelling and Software, Vol. 24, No. 12, pp. 1467-1482.
10
Ferziger, J. H., and Peric, M. (1996). Computational methods for fluid dynamics. Springer Verlag, Berlin, Germany.
11
Fukushima, Y., and Hayakawa, N. (1990). “Analysis of inclined wall plume by the k-ε turbulence model.” Journal of Applied Mechanics, Vol. 57, pp. 455-465.
12
Garcia, M. H. (1990). Depositing and eroding sediment-driven flows: turbidity currents. University of Minnesota, Minneapolis, Minnesota, USA.
13
Gibson, M., and Launder, B. (1976). “Ground effects on pressure fluctuations in the atmospheric boundary layer.” Journal of Fluid Mechanics, Vol. 86, No. 3, pp. 491-511.
14
Hossain, M. S., and Rodi, W. (1982). “Turbulence model for buoyant flows and its application to vertical buoyant jets.” Turbulent buoyant jets and plumes, Edited by W. Rodi, Pergamon Press, Oxford, pp. 121-178.
15
Kostic, S., and Parker, G. (2003). “Progradational sand-mud deltas in lakes and reservoirs. part 1. theory and numerical modeling.” Journal of Hydraulic Research, Vol. 41, No. 2, pp. 127-140.
16
Lai, Y. G., Huang, J., and Wu, K. (2015). “Reservoir turbidity current modeling with a two-dimensional layer-averaged model.” Journal of Hydraulic Engineering, Vol. 141, No. 12, p. 04015029.
17
Launder, B. E. (1975). “On the effects of a gravitational field on the turbulent transport of heat and momentum.” Journal of Fluid Mechanics, Vol. 67, pp. 569-581.
18
Ohey, C. D., and Schleiss, A. J. (2007). “Control of turbidity currents in reservoirs by solid and permeable obstacles.” Journal of Hydraulic Engineering, Vol. 133, No. 6, pp. 637-648.
19
Paik, J., Eghbalzadeh, A., and Sotiropoulos, F. (2009). “Three- dimensional unsteady RANS modeling of discontinuous gravity currents in rectangular domains.” Journal of Hydraulic Engineering, Vol. 135, No. 6, pp. 505-521.
20
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.
21
Rodi, W. (1984). Turbulence models and their applications in hydraulics. International Association for Hydraulic Research, Delft, The Netherlands, Monograph.
22
Ryu, I. G., Chung, S. W., and Yoon, S. W. (2011). “Modelling a turbidity current in Soyang reservoir (Korea) and its control using a selective withdrawal facility.” Water Science and Technology, Vol. 63, No. 9, pp. 1864-1872.
23
Stacey, M. W., and Bowen, A. J. (1988). “The vertical structure of density and turbidity currents: theory and observations.” Journal of Geophysical Research: Oceans, Vol. 93, No. C4, pp. 3528-3542.
24
Svensson, U. (1980). On the numerical prediction of vertical turbulent exchange in stratified flows. Proceeding of 2nd International Symposium on Stratified Flows, Trodheim, Norway.
Information
  • Publisher :KOREA WATER RESOURECES ASSOCIATION
  • Publisher(Ko) :한국수자원학회
  • Journal Title :Journal of Korea Water Resources Association
  • Journal Title(Ko) :한국수자원학회 논문집
  • Volume : 50
  • No :9
  • Pages :637-646
  • Received Date : 2017-05-16
  • Revised Date : 2017-07-31
  • Accepted Date : 2017-07-31
  • DOI :https://doi.org/10.3741/JKWRA.2017.50.9.637
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