The Forces acting on Two Circular Cylinders of arbitrary Radii placed in a Uniform Stream at Low Values of Reynolds Number

The steady slow motion of a viscous fluid past two parallel circular cylinders C 1 , C 2 of arbitrary radii is discussed on the basis of Oseen's linearized equations of motion, confining ourselves to the case when their axes are perpendicular to a uniform flow. The forces acting on the cylinder C 1 are calculated to the first approximation. By performing detailed numerical calculations, a discussion is made on the manner in which the forces acting on the cylinder C 1 is modified by the presence of the other cylinder C 2 . It is thus found that, as the radius of the cylinder C 2 increases, the drag on the cylinder C 1 decreases, while the lift increases. It is also found that the cylinder C 1 experiences smaller drag when the two cylinders are in tandem orientation than when they are placed side by side in a uniform stream. Especially, when the cylinder C 1 is situated behind the cylinder C 2 , it experiences smaller drag than when it is situated in front of C 2 .