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    A Reduced Order Hydroelastic Analysis of 3D Hydrofoil Considering Partial Sheet Cavitation Effects

    , Ph.D. Dissertation Sharif University of Technology Alavi, Mahdi (Author) ; Haddadpour, Hassan (Supervisor) ; Dehghani Firouz-abad, Roohallah (Co-Supervisor)
    Abstract
    In this Thesis hydroelastic analysis of 3D hydrofoil is investigated while partial sheet cavitation effects are considered. To this aim, first steady cavity boundary must be recognized.This region is calculated by means of conventional iterative procedure, stood upon potential flow theorem. In the second step, the reduced order fluid dynamics equations are derived based on potential flow theorem along with finite element method. This procedure is done in a way that real time system of equations are derived and iterative algorithm of conventional methods is omitted. To this aim, it is assumed that amplitude and frequency of the body oscillations are altered so that the cavity length in... 

    An improved progressive preconditioning method for steady non-cavitating and sheet-cavitating flows

    , Article International Journal for Numerical Methods in Fluids ; Volume 68, Issue 2 , December , 2012 , Pages 210-232 ; 02712091 (ISSN) Esfahanian, V ; Akbarzadeh, P ; Hejranfar, K ; Sharif University of Technology
    2012
    Abstract
    An improved progressive preconditioning method for analyzing steady inviscid and laminar flows around fully wetted and sheet-cavitating hydrofoils is presented. The preconditioning matrix is adapted automatically from the pressure and/or velocity flow-field by a power-law relation. The cavitating calculations are based on a single fluid approach. In this approach, the liquid/vapour mixture is treated as a homogeneous fluid whose density is controlled by a barotropic state law. This physical model is integrated with a numerical resolution derived from the cell-centered Jameson's finite volume algorithm. The stabilization is achieved via the second-and fourth-order artificial dissipation... 

    Hydroelastic analysis of two degree of freedom hydrofoil using a reduced-order hydrodynamic model considering unsteady partial sheet cavity flows

    , Article Journal of Fluids and Structures ; Volume 81 , 2018 , Pages 116-130 ; 08899746 (ISSN) Alavi, S. M ; Haddadpour, H ; Dehghani Firouz Abadi, R ; Sharif University of Technology
    Academic Press  2018
    Abstract
    In the present study a new, fast, precise algorithm for studying hydroelastic stability of a typical section with two degrees of freedom (2DOF) is proposed based on the finite element method (FEM), while the partial sheet cavitation effects are considered. For this means, the steady cavity boundary is calculated by some conventional iterative procedures, developed based on the potential flow simulation. Thereafter, assuming that the amplitude and the frequency of the body oscillations are altered so that the cavity length in unsteady flow remains unchanged, the simulation of the unsteady hydrodynamic flow is performed by imposing some velocity fluctuations over the rigid cavity boundary. For... 

    An Experimental Investigation on the Effects of Artificial Cavitation Generators on Control and Stabilization of Cloud Cavitation

    , M.Sc. Thesis Sharif University of Technology Shiraghaee Koutenaee, Shahab (Author) ; Javadi, Khodayar (Supervisor)
    Abstract
    The present study is aimed at investigating experimental methods to control and stabilize the oscillatory effects of sheet/cloud cavitation. Two methods were investigated: The use of artificial cavitation generating appendages, which had a two dimensional geometry similar to that of vortex generators. Employing air injection into the cavity from different locations on the chord of the hydrofoil and a comparison of the stability achieved from each case by analyzing pictures captured from a high-speed camera. To conduct these experiments, a cavitation tunnel along with measurement devices were used. Four different appendages were tested as artificial cavitation generators, which were in two...