Virginia Institute of Marine Science
A compilation of 761 observations of scour-induced burial and 406 observations of initiation of motion of UXO-like objects are presented. The main factors that increase the scour-induced burial-to-diameter ratio (B/D) under (i) currents and (ii) waves are the (i) Shields parameter (S) and (ii) Keulegan-Carpenter number. For cylinders under waves, B/D additionally increases as the current component parallel to wave orbitals decreases, as S increases, and as the angle between wave orbitals and a cylinder’s axis increases. Cylinders bury most, then spheres, and conical frustums bury least. Simple models dependent on these variables explain 85% of observed variance in B/D. Onset of motion is parameterized by fi S_Ucrit, where S_Ucrit is the critical object mobility parameter, and fi accounts for inertia forces from time-varying pressure gradients. S_Ucrit is observed to decrease systematically as D/k increases, where k is the bed roughness. Theory combined with observations lead to fi S_Ucrit = a1(D/k)^b1. Observations give a1 = 1.75 and b1 = - 0.72, which explains 89% of the observed variance in fi S_Ucrit.
Final report to the Strategic Environmental Research and Development Program (SERDP) associated with SERDP Project MR-2224
underwater munitions, unexploded ordnance, scour-induced burial, initiation of motion
Friedrichs, C., Rennie, S. E., & Brandt, A. (2018) Simple Parameterized Models for Predicting Mobility, Burial and re-exposure of underwater munitions. SERDP Final Report MR-2224. Virginia Institute of Marine Science, College of William and Mary. https://doi.org/10.25773/gk95-bb88