THE UNSTEADY STOKES RESISTANCE OF ARBITRARILY ORIENTED, FINITE-LENGTHCYLINDERS

The unsteady (oscillatory) Stokes resistance is numerically computed f or finite-length, circular cylinders using a first-kind, boundary inte gral formulation for low and moderate dimensionless frequencies. Trans lational oscillations parallel and perpendicular to the cylinder axis (axial and transverse oscillations) are considered. For arbitrarily or iented cylinders with length-to-width ratios in the range: 1/10 less-t han-or-equal-to a/b less-than-or-equal-to 10, a simple, previously pro posed, expression accurately (+/-5%) describes the oscillatory Stokes resistance at all frequencies in terms of steady Stokes and inviscid f low resistance parameters. Numerical calculations for spheroids agree with previous results; the results for cylinders and transverse oscill ations of oblate spheroids are new.