Cylinder drag at low Reynolds number

From terminal velocity measurements of solitary finite length circular cylinders settling in a large rectangular tank of fluid, drag values for infinite length circular cylinders translating at constant speed through an unbounded fluid were obtained. The drag was determined as the effective weight of the cylinder in the liquid and the Reynolds number was determined from the terminal velocity measurements by the time of flight method. The effects of finite length and finite boundaries were accounted for by empirical corrections. The effects of the container endwalls and bottom were observed to be negligibly small. The sidewalls caused a variation in the terminal velocity proportional to the reciprocal of the wall separation squared. When the influence of the side walls was removed, it was found that the reciprocal of the terminal velocity was linearly proportional to the reciprocal of the length.