Immortal Science Of Dead Water: Effects Of Internal Wave Drag On Submersibles
Naval Postgraduate School Monterey United States
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Drag evaluation and prediction have always been integral to maximizing the efficiency of nautical vehicles. Yet, the total friction acting on a body moving in a fluid can be difficult to predict even today. In this regard, a still poorly understood source of drag with significant effects for vessels sailing in stratified waters is the so-called dead-water phenomenon. The dead-water phenomenon represents the dramatic increase in drag associated with radiation of internal waves created by the body itself. This phenomenon has been studied in the literature for surface vessels, but little attention has been given to the extent that dead-water affects submersibles. To address this issue, our research investigates the dead-water effects on a cylindrical body, comparing laboratory and numerical outcomes for both submerged and floating body experiments. Our results show more pronounced dead-water effects for submersibles than for boats, showing greater velocity loss a factor of 1.28 and larger power loss a factor of 2.4. These results have major implications for military operations. In particular, they show how a thorough understanding of dead-water effects can significantly increase the performance of naval vessels by improving their maneuverability and fuel consumption characteristics.
- Physical and Dynamic Oceanography
- Submarine Engineering