Arash Eslamdoost

Net and Gross Thrust in Waterjet Propulsion

The measurement of the net thrust of a waterjet unit is a cumbersome task and thus as an alternative, the thrust of the waterjet system is expressed based on the momen- tum flux change through the waterjet unit, called gross thrust. The relation between net thrust and gross thrust is not fully understood, and in the current paper this relation is investigated by employing numerical simulations of the flow around a planing waterjet- propelled hull. The validation of the bare hull and self-propelled hull simulations is carried out through comparison of the computed results with experimental data.

Waterjet Propulsion and Thrust Deduction

The goal of this article is to describe and investigate the parameters that play a role in the waterjet–hull interaction. In general, these parameters can be split into sinkage, trim, and local flow variation from the bare hull to the self-propelled hull. Each of these parameters has in turn been split into components, which are estimated in relative size. For this purpose, a newly developed method for modeling waterjet-driven ves- sels is used. Knowing the magnitude of each single parameter separately helps to understand the physics behind the thrust deduction and may aid in the optimization of the hull/propulsor configuration.