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Flows past bluff bodies are encountered in many engineering applications. The bluff body situated in the flow experience a significant amount of pressure drag force. Therefore, it is important to predict flow conditions around bluff bodies when designing bridges, platforms, pipelines near seabed, offshore structures, and hydropower systems. In several engineering applications, structures could often be placed near surfaces. Transient flows past rectangular plates in the vicinity of surfaces are investigated in this study.

Large eddy simulations of ventilated hydrokinetic turbine and pump-turbine are conducted. The mathematical modeling of oxygen dissolution and the flow model employed were validated by comparing predicted dissolved oxygen concentration against reported experimental measurements. A parametric study is performed to investigate the influence of interfacial forces, surface tension and bubble breakage and coalescence terms. It is demonstrated that aeration via hydrokinetic turbines can be used to improve the dissolved oxygen level in rivers for better water quality.

Computational fluid dynamics simulations were conducted to study the performance of a Francis turbine operating at various flow rates spanning from ultra-low to excessive load. Francis turbine used in this study is rated at an industrial size of 1MW. High-fidelity large eddy simulations (LES) were utilized to characterize the cavitating turbulent flow structures inside the turbine unit. The axial, peripheral, and tangential water injections from the runner crown center and draft tube wall are considered to stabilize the turbine operation.