Application of volume of fluid (VOF) method in conjunction with shear stress transport (SST) k-ω turbulence closure model to investigate spillway flow

Bayrakdar, Fatih
Hydraulic engineers often require to assess the reasons and consequences of interaction of flow with structures. Computational Fluid Dynamics (CFD) became a useful tool in this regard in recent years as it provides ample amount of information both on flow and its interaction with its surrounding. To this end, flows over a spillway are investigated. The computational domain for the flow over a spillway is based on the study by Dargahi (2006). Numerical results are compared to previous experimental ones. In the study, SST k-ω Model is considered for turbulence closure. The free surface of these flows is simulated using Volume of Fluid (VOF) approach. The effect of spillway roughness, scale of the model, and the downstream conditions are discussed for a single spillway structure. The scale effects have shown that cavitation related studies should be carried using prototype scales in numerical simulation of spillway flows. If the roughness is accounted only as a constant in governing equations in Reynolds-Averaged-Navier-Stokes (RANS) simulations, current study shows that its effect may not be captured pronouncedly. Downstream conditions imposed in the model could produce simple hydraulic jump conditions. In these cases, air-entrainment due to jump is calculated based on aerated fluid volume. 


Development and evaluation of new bleed boundary condition models for supersonic inlet boundary layer bleed flow
Akar, Gökhan; Eyi, Sinan; Department of Aerospace Engineering (2019)
Shock wave/boundary layer interaction is an important issue that should be considered when studying supersonic inlet design for air vehicles. Porous bleed systems have traditionally been used for increase stability and efficiency of the supersonic inlets by means of removing the lower momentum part of the boundary layer to prevent flow separation caused by adverse pressure gradient. However, evaluating and determining the effect of the boundary layer bleed system on the performance of the supersonic inlet i...
Numerical investigation of hydraulic characteristics of Laleli Dam spillway and comparison with physical model study
Usta, Eray; Köken, Mete; Department of Civil Engineering (2014)
Spillway is a hydraulic structure that is used to pass big discharges in flood times in a controlled manner and release surplus water that cannot be safely stored in the reservoir to downstream. During the design process of the spillways, determining of hydraulic behavior of these structures is a very significant issue for an accurate and optimum design. In this thesis, the objective is to investigate the hydraulic characteristics of the flow over Laleli dam spillway numerically and compare the results with...
Improving flow structure and natural convection within fin spacings of plate fin heat sinks
Özet, Mehmet Erdem; Tarı, İlker; Department of Mechanical Engineering (2015)
The main objectives of this thesis are to numerically investigate the previously observed recirculation zones and longitudinal vortices that occur in low fin height plate finned horizontal heat sinks and to improve the flow structures and heat transfer in these zones using various approaches with the help of simulations performed using commercially available CFD software. The approaches used for improvements are replacing the outer most fins with higher ones, introducing gaps on the length of the fins in va...
Theory of impurity induced lattice distortions in the normal phase of charge density wave systems
Turgut, Sadi (1994-05-01)
A phenomenological Ginzburg-Laundau theory is applied to the normal phase of one-dimensional charge-density-wave systems with a finite concentration of impurities. It is found that the interaction between the impurities and the highly polarizable electron gas leads to a strong and oscillatory impurityimpurity interaction, which in turn leads to ordered impurity arrangements and to sizeable periodic lattice distortions. The effect is very strongly dependent on the charge of the impurities, their concentratio...
Application of spring analogy mesh deformation technique in airfoil design optimization
Yang, Yosheph; Özgen, Serkan; Department of Aerospace Engineering (2015)
In this thesis, an airfoil design optimization with Computational Fluid Dynamics (CFD) analysis combined with mesh deformation method is elaborated in detail. The mesh deformation technique is conducted based on spring analogy method. Several improvements and modifications are addressed during the implementation of this method. These enhancements are made so that good quality of the mesh can still be maintained and robustness of the solution can be achieved. The capability of mesh deformation is verified by...
Citation Formats
F. Bayrakdar, “Application of volume of fluid (VOF) method in conjunction with shear stress transport (SST) k-ω turbulence closure model to investigate spillway flow,” M.S. - Master of Science, Middle East Technical University, 2017.