Al-Mdallal, Qasem M. (2004) Analysis and computation of the cross-flow past an oscillatiang cylinder with two degrees of freedom. Doctoral (PhD) thesis, Memorial University of Newfoundland.
- Accepted Version
Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission.
The present thesis deals with analysis and numerical simulation of a new class of wake flows created by combined recti-linear (translational) and rotational oscillation of a cylinder placed in a steady uniform flow. The flow is incompressible and two-dimensional, and recti-linear and rotational oscillations are harmonic. The instantaneous translation and rotation start at the same moment and the development of the flow is studied in a coordinate frame which moves with the cylinder but does not rotate. The analysis is carried out for combined phase-locked translation and rotation with a single frequency. The results are presented for five set of the four dimensionless groups which characterize this flow. The resulting vortex formation modes and synchronization (lock-on) phenomena behind the cylinder (in the near-wake region) as well as the fluid forces acting on the cylinder are analyzed. In addition, a series of one-degree-of-freedom (1-DoF) forced vibration calculations are carried out to better understand what differences result from the addition of rotational oscillations to streamwise (in-line) or cross-stream (transverse) motion and to see which effects a transverse-only or in-line-only simulations miss. The numerical scheme is verified by applying it to the special cases of uniform flow past a stationary cylinder; a steadily rotating cylinder; a cylinder undergoing (1-DoF) forced (recti-linear or rotational) oscillations. Exceptionally good comparisons with previous experimental and numerical results are obtained. Furthermore, the simulations of the start-up flow for the case of combined (2-DoF) forced recti-linear and rotational cylinder oscillations at a moderate Reynolds number are consistent with the results of the analytical solution.
|Item Type:||Thesis (Doctoral (PhD))|
|Additional Information:||Includes bibliographical references (leaves 255-262)|
|Department(s):||Science, Faculty of > Mathematics and Statistics|
|Library of Congress Subject Heading:||Cross-flow (Aerodynamics)--Mathematical models; Cylinders--Fluid dynamics; Oscillations--Mathematical models; Rotating masses of fluid--Mathematical models|
Actions (login required)