| dc.description.abstract | The modern maritime engineering industry uses various types of structures in their fields. The single circular cylinder is the core and basic structure of the industry which is studied with numerical and experimental methods. The present study focuses on the flow around the inclined cylinder by using numerical simulations with several cases.
This study consists of three parts. First, a simple two-dimensional circular cylinder is chosen to get familiar with the theoretical problem and software Open FOAM. Simulation is performed with the circular cylinder being submerged in the fluid with Reynolds number 100. In the present study, the main parameters such as domain size, time step, element size are investigated with various simulation cases. The results analyzed based on the hydrodynamic quantities regarding mean drag and RMS of lift coefficient and Strouhal number. Besides, the visualization of velocity, vorticity is shown for certain scheme. The results are compared with the previous study s results to check the validity.
The second one is three-dimensional simulations stationary cylinder with different Reynolds number, Re=100, 300. The purpose to simulate these cases is to check the three-dimensional effect when it changes from two-dimensional simulation and checks the computational domain height effect. Additionally, it also checks the difference between different Reynolds number effect by using ISO-surface and compared the results with previous studies values to test the validity of methodology.
The last part, inclined cylinder, consists of three different Reynolds number, Re=300, 500 and 700. The inclination angles are investigated with each case. The different computational domain heights (L/D=4, 8, 12) are investigated with Re=300 to check the differences among these cases. Additionally, it also states the numerical error because of the symmetric boundary condition limit. The velocity vector is provided to show how the fluid flows after it passes the inclined cylinder. Additional computational time and opposite inclination angle are performed to check the fluid s flow directions. Each X-Y plane with different Z-position is investigated to check different vorticity. All results are compared with the independence principle calculated values to check how much they deviate.
In Re=500, 700 the force coefficients are compared how they change after increased Reynolds number. ISO-surface is also compared with different Reynolds number, and only two computational domain heights (L/D=8, 12) are investigated. Streamlines are also investigated on different inclination angle with Re=700. The same plane with different inclinations is investigated how the vorticity and velocity changes. These results are also compared with the independence principle calculated values.
The manuscript of Open FOAM called ControlDict file and Matlab are included in Appendix. Also, the other Figures which couldn t include on the thesis paper are included in Appendix. | en |
