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Hydrodynamic interaction between cylinders at moderate Reynolds numbers

University of British Columbia

The hydrodynamic interaction between two cylinders perpendicular to the freestream, in a tandem arrangement was studied for moderate Reynolds numbers (1≤Re≤40). The influence of multiple geometric variables was considered: separation distances between the cylinders, ellipticity of the cylinders, the cylinder aspect ratio, and the angular inclination between the cylinders. In the first part of this study, a numerical investigation of the two-dimensional steady flow past cylinders was carried out. The characteristic length, D, in all simulations was taken to be twice the major axis of the cylinder cross-section, (i.e. equal to the diameter for cylinders of circular cross-section). The two-dimensional flow was studied for separations up to 50D. Four different ellipticities were studied. The drags experienced by front and rear cylinders were compared with that experienced by a single cylinder of the same cross-section. The second part of the study consisted of the steady three-dimensional flow analysis for parallel cylinders in tandem for separations ranging from 2D to 20D and cylinder lengths up to 20D. In the third part of this thesis, a steady flow analysis was done for two circular cylinders in tandem with lengths equal to 5D but with the cylinder axes in different orientations relative to the plane normal to the flow. This angular separation between the cylinders produces a hydrodynamic moment, which is dependent on the geometry and the flow Reynolds number. The fourth and final part of this work is the study of the unsteady three-dimensional flow that would result from the hydrodynamic moment discussed in relation to the third part of the thesis. The thesis closes with some remarks on the implications of these findings to papermaking and recommendations for future work.

Text

2013-07-31

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/44730

Mechanical Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/