Slow Flow of a Viscoelastic Fluid Past a Circular Cylinder

• Main Author: Wang, Edwin Shao Wen
• Other Authors: James, David F.
• Language: en_ca
• Published: 2012
• Subjects: Fluid Mechanics; Rheology; 0548
• Online Access: http://hdl.handle.net/1807/32289

Flow around a cylinder is important in the motion of microorganisms found in biological viscoelastic fluids that propel themselves by flagella. Flow around a cylinder experiments are difficult to perform because of the influence of the walls and ends. An approach was developed to measure the drag on a cylinder by correcting for wall and end effects. Cylinders were vertically dipped into fluids in an annular shaped tank, which was rotated to generate a flow. The force acting on a cylinder was measured using a custom force transducer. This method was used for a Newtonian fluid and two Boger fluids. The drag of the Boger fluids was several times that of an equivalent Newtonian fluid. A cavity was observed to develop behind the cylinders once the flow surpassed a critical velocity. Streakline images taken during the experiment confirmed the presence of a wake region behind the cylinders.