Stokes Drag on a Thin Circular Disk Moving Edgewise Midway Between Parallel Plane Boundaries

This technical brief presents experimental results for the drag on a circular disk moving at terminal velocity through a viscous fluid midway between parallel plane walls. The axis of the disk is oriented perpendicularly to these walls. The notation is shown in Fig. 1. A circular disk of diameter $d$ and thickness $t$ moves edgewise with a velocity $U$ through a viscous fluid of density $ρ$ and viscosity $μ$ midway between two plane walls that are parallel to the plane of the disk. The distance between the parallel walls is $D$⁠. Define the aspect ratio of the disk as $A=t∕d$ and the Reynolds number as $Re=dρU∕μ$⁠. I will assume that the flow is a Stokes flow $(Re⪡1)$ and that the disks are thin $(A⪡1)$⁠.