COMPUTATIONAL MODELLING OF ADVANCED FLOW CHARACTERISTICS IN AERATED HIGH ENERGY SPILLWAYS

摘要

The hydrodynamics in open channel flows are most challenging and obey complex physical laws. To choose the distance from the inlet of a spillway for an aeration device located on the spillway bottom to prevent the occurrence of cavitation is mostly a function of the channel slope, friction factor and water discharge. Nevertheless, for an accurate determination the evolvement of an aerated flow depending on bubble size and its distribution, suspended particles and the geometry of the aerator have to be taken into account. In this work, the analogy between a bubbly water flow in a tube and that of in a mixing tank compared to the flow behavior of an aerated spillway is used to distinguish the physical complexity. The analysis is mainly based on numerical modelling which is a combined large-eddy simulation technique (LES) and disceret element method. Threedimensional simulations of an aerator are performed on a graphics processing unit (GPU). The simulation results are in agreement with the aforementioned experiments and confirm prior findings from physical models such as formation of bubble size, bubble coherence and separation and air concentration profiles. This promising effort in GPU computing could pave the way for developing advanced simulation techniques for the study of waterways and ports, as well as coastal and ocean engineering in the future.