Analysis and Extension of Theory for Predicting Propeller Field Pressures and Blade Forces Due to Cavitation

摘要

A theoretical analysis which allows prediction of field pressure and blade forces for a transient cavitating propeller in a ship wake is fully described. The representation of sectional blade loading is considered in terms of two models; one which assumes the unsteady loading to be due to an unsteady angle of attack, and the other which assumes it is due to combined unsteady angle of attack and unsteady camber. The results for the cavity configuration and its angular region of occurrence differ for each model, and similarly for the pressures and forces. Comparison with both the general observed pattern of transient propeller cavitation in a ship wake, as well as the specific case of particular propellers, supports the model with unsteady angle of attack alone as the proper representation to be used with the present approach.