Aspect ratio effects on circular cylinder drag at low Reynolds numbers

Design of small uninhabited aerial vehicles is hampered by the relatively sparse database available for aerodynamic properties of basic shapes at low Reynolds number (Re). As a step towards remedying this situation, an experimental investigation of the influence of aspect ratio on the drag of circular cylinders at low Re has been conducted. The experiment itself faced the difficulty of measuring the small forces associated with low Re. A novel solution to this problem has been developed and applied in the Patterson Hall low speed wind tunnel at Mississippi State University. Using this method the drag characteristics of cylinders with aspect ratios varying from 16 down to 1 over a Reynolds number range from 105 down to 104 have been measured. This presentation will discuss the existing database, the present experimental method and the results that have been obtained.