Advertisement

Two-Phase CFD Modeling of Sediment Plumes for Dredge Disposal in Stagnant Water

  • S. N. ChanEmail author
  • Adrian C. H. Lai
  • Adrian W. K. Law
  • E. Eric Adams
Conference paper
  • 56 Downloads
Part of the Springer Water book series (SPWA)

Abstract

Dredge spoil is commonly disposed in estuarine and coastal waters through submerged pipelines from a barge in the form of concentrated mixture of sediment and water. The discharge resembles a downward dense turbulent plume under the negative buoyancy of the sediment particles. Sediment discharge can increase the turbidity and suspended solid level of coastal water, causing damage the marine ecosystem. It is important to understand the mixing of a sediment plume with the ambient water in order to properly assess the environmental impact of disposal operation. This chapter presents a computational fluid dynamics (CFD) model of a sediment plume in a non-stratified stagnant ambient using the two-phase Eulerian approach. The axisymmetric two-phase continuity and momentum equations are solved with the drag force term accounting for the interaction between phases. The standard k-ε model is used for turbulence closure for sediment-water mixture. The radial turbulent dispersion of particles is modeled by a drift velocity term related to the concentration gradient of the particle phase. The model prediction is validated against experiments of a companion work and independent experimental data, with a wide range of particle sizes (68–1500 μm) and plume sediment volume fraction (maximum of 60%). The model predicted cross-sectional distribution of sediment concentration, plume fluid velocity and the slip velocity of particle to fluid can be well described by Gaussian profiles. The reduction of plume spreading rate with increasing particle size and settling velocity is also well predicted by the model. The CFD model results shed light on the development of a simple integral model for predicting the mixing of sediment plumes.

Keywords

Sediment plumes CFD Eulerian two-phase model Volume fraction Sediment disposal 

Notes

Acknowledgements

This research was supported by the National Research Foundation Singapore through the Singapore-MIT Alliance for Research and Technology’s Center for Environmental Sensing and Modeling interdisciplinary research program. The first author was partly supported by a research grant from the Institute for Advanced Study of the Hong Kong University of Science and Technology.

References

  1. ANSYS FLUENT version 15.0 [Computer software]. (2013). Canonsburg, PA: ANSYS.Google Scholar
  2. Azimi, A. H., Zhu, D. Z., & Rajaratnam, N. (2011). Effect of particle size on the characteristics of sand jets in water. Journal of Engineering Mechanics, 137(12), 822–834.CrossRefGoogle Scholar
  3. Azimi, A. H., Zhu, D. Z., & Rajaratnam, N. (2012). Computational investigation of vertical slurry jets in water. International Journal of Multiphase Flow, 47, 94–114.CrossRefGoogle Scholar
  4. Chan, S. N., & Lee, J. H. W. (2016). A particle tracking model for sedimentation from buoyant jets. Journal of Hydraulic Engineering, 142(5), 173–200.Google Scholar
  5. Chan, S. N., Lee, K. W. Y., & Lee, J. H. W. (2014). Numerical modelling of horizontal sediment-laden jets. Environmental Fluid Mechanics, 14(1), 173–200.CrossRefGoogle Scholar
  6. Crowe, C. T., Schwarzkopf, J. D., Sommerfeld, M., & Tsuji, Y. (2012). Multiphase flows with droplets and particles. FL: CRC Press.Google Scholar
  7. Cuthbertson, A. J. S., & Davies, P. A. (2008). Deposition from particle-laden, round, turbulent, horizontal, buoyant jets in stationary and coflowing receiving fluids. Journal of Hydraulic Engineering Division of the American Society of Civil Engineers, 134(4), 390–402.CrossRefGoogle Scholar
  8. Hall, N., Elenany, M., Zhu, D. Z., & Rajaratnam, N. (2010). Experimental study of sand and slurry jets in water. Journal of Hydraulic Engineering, pp. 727–738.  https://doi.org/10.1061/(ASCE)HY.1943-7900.0000235.
  9. Lai, A. C. H., Chan, S. N., Law, A. W. K., & Adams, E. E. (2016). Spreading hypothesis of a particle plume. Journal of Hydraulic Engineering Division of the American Society of Civil Engineers, 142(12), 04016065.CrossRefGoogle Scholar
  10. Launder, B. E., & Spalding, D. B. (1974). The numerical computation of turbulent flows. Computer Methods in Applied Mechanics and Engineering, 3, 269–289.CrossRefGoogle Scholar
  11. Lee, J. H. W., & Chu, V. H. (2003). Turbulent jets and plumes: A Lagrangian approach. New York: Springer.CrossRefGoogle Scholar
  12. Morton, B. R., Taylor, G. I., & Turner, J. S. (1956). Turbulent gravitational convection from maintained and instantaneous sources. Proceedings of the Royal Society of London. Series A, 234(1196), 1–23.Google Scholar
  13. Nguyen, D. H., Levy, F., Bang, D. P. V., Guillou, S., Nguyen, K. D., & Chauchat, J. (2012). Simulation of dredged sediment releases into homogeneous water using a two-phase model. Advances in Water Resources, 48, 102–112.CrossRefGoogle Scholar
  14. Parthasarathy, R. N., & Faeth, G. M. (1987). Structure of particle-laden turbulent water jets in still water. International Journal of Multiphase Flow, 13(5), 699–716.CrossRefGoogle Scholar
  15. Schiller, L., & Naumann, Z. (1935). A drag coefficient correlation. Z. Ver. Deutsch. Ing., 77, 318.Google Scholar
  16. Virdung, T., & Rasmuson, A. (2007). Hydrodynamic properties of a turbulent confined solid-liquid jet evaluated using PIV and CFD. Chemical Engineering Science, 62, 5963–5979.CrossRefGoogle Scholar

Copyright information

© Springer Nature Singapore Pte Ltd. 2020

Authors and Affiliations

  • S. N. Chan
    • 1
    Email author
  • Adrian C. H. Lai
    • 2
  • Adrian W. K. Law
    • 2
  • E. Eric Adams
    • 3
  1. 1.Department of Civil and Environmental Engineering and Institute for Advanced StudyThe Hong Kong University of Science and TechnologyHong KongChina
  2. 2.Nanyang Environment and Water Research Institute and School of Civil and Environmental Engineering, Nanyang Technological UniversitySingaporeSingapore
  3. 3.Department of Civil and Environmental EngineeringMassachusetts Institute of TechnologyCambridgeUSA

Personalised recommendations