FLUID FLOW IN COMPLEX CYLINDRICAL GEOMETRIES

Flows in packed beds, porous media, and circulatory systems all involve channels with changes in cross sectional area and low or moderate Reynolds numbers. While a considerable amount of attention has been focused on low Reynolds number flows through conduits with gradual changes in cross section, much less has been done for conduits with abrupt changes.; Analytical solutions to the problems of creeping flow through a thin orifice or a sudden contraction or expansion in a tube are obtained in this dissertation. A matched eigenfunction expansion method is used. It involves dividing a spatial domain into regions in which separate analytical solutions can be obtained and then imposing continuity conditions on the solutions along common boundaries of the regions. This latter step also ensures the uniqueness of the solution.; Flow fields for various constriction ratios are evaluated. Streamline patterns, constant vorticity contours, and velocity profiles are determined. The existence of corner recirculating cells is examined. Local similarity solutions are constructed to explore flow separation. Results also include excess pressure drops and separation distances. The values obtained in this investigation approach previously established asymptotes in limits.