Resistance In Unsteady Flow: Search For an In-line Force Model

This paper offers an improvement to the Morison, O'Brien, Johnson, and Schaaf (MOJS, 1950) representation of the in-line force for a sinusoidally oscillating flow. The modification proposed herein consists of the addition of a third term, without the introduction of additional empirical coefficients. The three-term model is expected to offer greater universality and higher engineering reliability, particularly in the inertia-drag regime where the original MOJS equation fails.