Seminar - John Patterson - Mixing and transport processes in lakes and reservoirs

Wednesday 21 April 2010, 4.00 pm - 5.00 pm
Civil Engineering Lecture Theatre 3

Professor John Patterson
School of Civil Engineering
University of Sydney

Abstract:
Lakes and reservoirs although seemingly often tranquil and peaceful are usually controlled by a highly complex collection of interacting, non linear, transient turbulent processes which control the properties of the stored water driven by the various forcings such as the wind, surface heating and cooling, inflows etc.. The principal parameter controlling the dynamics of lakes, and therefore the distribution of water quality parameters, is temperature or some other density determining property such as salinity. Although full 3D CFD simulation is becoming increasingly possible it is still far too computationally expensive to be of practical use, and ‘black box’ modelling is unreliable outside the range of calibration data. However it is possible to make an assumption which allows significant simplification, decoupling the processes. We may then make use of a powerful technique called scaling analysis to provide simple descriptions of the processes, and link these together to construct operational models. In this talk I will discuss the basis of the simplifying assumption and the way in which this method is applied to some of the processes.