RANS computation of propeller tip vortex flow for steady and unsteady cases

Mintu, Md. Shafiul Azam (2011) RANS computation of propeller tip vortex flow for steady and unsteady cases. Masters thesis, Memorial University of Newfoundland.

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Abstract

CFD simulations were conducted for different marine propellers at steady and unsteady flow conditions using a commercial RANS solver ANSYS ® CFX ®. For steady simulation, a spiral-like domain aligned with the vortex core was generated with structured grids. The simulation was validated with the David Taylor Model Basin DTMB 5168 propeller model at open-water condition. -- Various eddy viscosity turbulence models and Reynolds-stress models were employed in the computations. The effect of the turbulence modeling on the solution was investigated. The blade surface pressure and the propeller performance were also computed. The simulation data were compared with the experimental data. -- The unsteady simulation was conducted for propeller at inclined flow condition. A single domain was generated with structured grids. A simulation technique for inclined flow condition was presented. The simulation was validated with the model test data of DTMB 4718 at design condition. A fully implicit coupled solver was used. A segregated solver with Incomplete Lower Upper (ILU) factorisation technique was employed in the simulation. Algebraic Multi-grid (MG) model was used to accelerate the convergence. Advection terms were descretised by high resolution scheme while the viscous terms were treated by employing central difference scheme. The transient terms were descretised with Second Order Backward Euler scheme. The Shear Stress Turbulence model was employed in the computation. -- The effect of grid sensitivity and domain size were investigated. The periodic loadings on the pressure and suction sides of the blades were compared with the experimental data. Reasonable agreement with the computed amplitude of the pressure variations was found. The predictions of the phase of the pressure variations were less favourable. -- This work is the first attempt of the CFD simulation for unsteady propeller flow investigation using a spiral like computational grid. Further improvements and extensions of this work can be made. Suggestions are made regarding future work on the use of CFD simulations of propeller flow.

Item Type: Thesis (Masters)
URI: http://research.library.mun.ca/id/eprint/9668
Item ID: 9668
Additional Information: Bibiography: l. 93-99.
Department(s): Engineering and Applied Science, Faculty of
Date: 2011
Date Type: Submission
Library of Congress Subject Heading: Ship propulsion--Mathematical models; Propellers--Cavitation; Underwater propulsion--Mathematical models; Ships--Hydrodynamic impact; Rotating masses of fluid

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