Universidad de Chile

Experimental study on transport, dispersion and mixing processes in lakes and estuaries

Principal investigator: Yarko Niño

Project funded by the Chilean National Science and Technology Fund, FONDECYT (Project Nº 1010483)

Years: 2001-2003

This research deals with the hydrodynamics of surface water systems, focusing mainly on the following aspects: 1) mixing and dispersion in stratified estuaries, 2) thermo-hydrodynamics of lakes and reservoirs, 3) ecological modeling of lakes and reservoirs, and 4) sediment resuspension and mass transfer at the water-sediment interface. This research is important to improve the present level of knowledge and understanding of mixing and turbulent transport processes in natural aquatic systems and therefore to improve our present capability to predict and reduce the impact of human activity on the environment. The research includes experimental and field studies and the development and application of numerical models. Experimentation is carried out in laboratory flumes to study stratified flow phenomena and columns to study sediment resuspension and mass transfer at the water-sediment interface. Experimental techniques include the use of ADV, LIF, PIV and PTV together with fast conductivity sensors. Numerical simulations are based on our own numerical models, on commercial software and DYRESM-CAEDYM models developed by the CWR of the University of Western Australia. Our numerical models use the k-epsilon turbulent closure model to resolve the vertical structure of stratified flows. We also have developed a density coupled, 2-D, depth-averaged model for flow and salinity transport in estuaries. Field studies have been carried out in the final reach of Maipo river in Central Chile, as it flows into the Pacific Ocean, and in Chungará Lake in northern Chile. Other systems studied in this project include Rapel and Peñuelas reservoirs in Central Chile, and Valdivia estuary and Villarrica Lake in South-central Chile.

Selected Publications:

de la Fuente, A. and Niño, Y. (2008) Pseudo 2D ecosystem model for a dendritic reservoir. Ecological Modelling. In press. doi:10.1016/j.ecolmodel.2008.01.020.

Ihle, C. and Niño, Y. (2006). The onset of nonpenetrative convection on a suddenly cooled layer of fluid. International Journal of Heat and Mass Transfer, Vol. 49, pp. 1442-1451.

Meruane, C., Niño, Y., and Garreaud, R. (2005). Estructura térmica del lago Villarrica (Chile) durante episodios de viento fuerte. Mediciones y simulación numérica. MECOM 2005, Buenos Aires, Argentina.

Meruane, C., Niño, Y., and Garreaud, R. (2005). Simulation of phytoplankton response to strong wind events in lake Villarrica, Chile. XXXI IAHR Congress. Seoul, Korea.

Loose, B., Niño, Y., and Escauriaza, C. (2005). Finite volume modeling of variable density shallow-water flow equations for a well-mixed estuary: application to the Río Maipo estuary in central Chile. Journal of Hydraulic Research, Vol. 43, No. 4, pp. 339-350.

de la Fuente, A., Niño, Y. (2004) Hydrodynamics and water quality of Rapel Reservoir in Central Chile. 5th Ecohydraulics Symposium. Madrid.

Niño, Y. and Miranda, J. F. (2003). Mixing in strongly stratified bottom cavities of estuaries: An experimental study. Archives of Hydro-Engineering and Environmental Mechanics, Vol. 50, No. 4, pp. 401-413.

Niño, Y., Caballero, R., and Reyes, L. (2003). Mixing and interface dynamics in a two-layer stratified fluid due to surface shear stress. Journal of Hydraulic Research, Vol. 41, No. 6, pp. 609-621.

Niño, Y., López, F., and García, M. (2003). Threshold for particle entrainment into suspension. Sedimentology, 50, pp. 247-263.