ANALYZING UUV HULL CROSS-SECTIONS FOR MINIMIZING WAVE LOADS WHEN OPERATING NEAR SURFACE

Abstract

This research considers square and rectangular cross-sectional shapes for unmanned underwater vehicle (UUV) parallel mid-bodies as a means for reducing wave-induced loads when operating near the surface. The inquiry is addressed through experimental model testing in a monochromatic wave environment with a circular cross-section model as a reference. The results suggest there is a loading difference between rectangular and circular models but little difference between circular and square cross-sections. An exponentially decaying depth dependency is observed for near-surface depths, which enables extrapolation of predicted forces and moments to other operating depths not tested. Reducing the depth further such that the distance between the surface and the vehicle center-line is less than the hull diameter exhibits a somewhat different behavior. This identifies a very-near-surface region where current modeling is inadequate. Non-circular hull designs can reduce wave-induced loads and effectively reduce operating depths for underwater vehicles. The findings support further research to determine optimal design points and to evaluate the effects of different designs on system architectures.