Analysis of the intake grill for marine jet propulsion

Abstract: Marine waterjet propulsion is a technology that has been developed and refined since the early 1950’ and is proven highly useful for high speed applications with vessels in varying sizes. The intake grill is a component that is mounted in line with the hull to prevent debris from traveling through the waterjet. The intake grill is affected by viscous forces, contact forces and harmonic excitation forces all while affecting the efficiency of the waterjet. In this report a selection of methods is evaluated and verified with the goal of simplifying the design process of the intake grill. A selection of cross-sections is generated and evaluated to draw general conclusions about the efficiency and stability of the intake grill. A selection of computational fluid dynamics and modal analysis methods are utilized. It is concluded that the intake grill is affected by many parameters and can be evaluated by modal FEM analysis and 2D CFD analysis.