Author(s): Muhammed Ucar; Serife Yurdagul Kumcu
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Keywords: No Keywords
Abstract: Circular dropshafts, commonly used in urban storm water systems for energy dissipation and flow control, are characterized by significant flow aeration. This study is made mainly for the two phase (air-water) physics of dropshafts. For this aim a series of laboratory tests having horizontal inflow and outflow conduits with of d=0.12m, and a circular drop tank having diameter of D=0.358 m were tested for observing flow patterns and to measure air bubble entering in the laboratory. Although experimental modeling studies have been used to succeed designing hardness as they directly indicate the systems, the studies are time consuming, commonly may not be economical and have heavy labor work. With the use of high performance computers and more efficient computational fluid dynamics (CFD) codes, the behavior of water in various types of hydraulic structures can be investigated numerically in reasonable time and expense. They also give quite successful results. In this study, FLOW-3D, which uses VOF (Volume of Fluid) method and solves RANS (Reynolds Averaged Navier-Stokes) equations, is used for mathematical modeling. Moreover, VOF (Volume of Fluid) method is also involving several advection solver methods within itself and each has its own formulations and thus results. Split-Unsplit Lagrangian methods and free surface method are such triad of the methods which are the comparisons made under approval of experiment. It is shown that the water profile, location and intensity of aeration are non-identical.
Year: 2018