Latest Engineering Trends in Surface Combatants' Design and Construction

The development of warships has been guided by the need for speed, range, firepower, and survivability at sea. However, to achieve speeds over 30 knots, it became apparent that the propeller material and design needed a change to ensure that cavitation effects are computer science vs engineering. The transit of propeller blades through water results in positive pressure on the blade face and negative pressure on its reverse side, the negative pressure causes the absorbed gases in the medium to bubble and later collapse on the reverse side of the propeller. 

The hammer-like impact of the collapsing bubbles causes damage to propeller blade surfaces and results in a drastic drop in its efficiency. The cavitation of propellers is a very complex phenomenon, and the pitting becomes visible on the reverse of the blade in a clear radial pattern. It may also happen to the driving face of the propeller in case there is an incorrect pitch distribution along the length. There are various types of patterns of propeller cavitation like face cavitation, tip vortex cavitation, bubble cavitation, sheet cavitation, cloud cavitation, root cavitation, and boss vortex cavitation. The loss of speed and damage to the propeller blades caused due to cavitation can be mitigated to an extent by correctly designing the propeller blade area relative to the area of the circle described by the propeller blade tips.