Evaluation of Cavitation and Noise Performance of Composite Propellers for Underwater Vehicles using a Large Cavitation Tunnel

Abstract

Unlike conventional metallic propellers, composite propellers for underwater vehicles exhibit hydroelastic deformation under operating loads and therefore require evaluation methods that account for both hydrodynamic loading and structural deformation. In this study, model tests based on Mach number scaling were conducted in a large cavitation tunnel to evaluate the cavitation and noise performance of composite propellers designed for an underwater vehicle. To reproduce full-scale hydroelastic response, model-scale self-propulsion conditions were derived for two metallic and two composite propellers. The validity of the proposed composite propeller design and evaluation procedure was assessed by comparing measured blade deformation with predictions from fluid–structure interaction (FSI) analysis, which showed that the two-way FSI approach provided close agreement with the measured deformation. Using the established Mach-scaled procedure, cavitation inception speed (CIS) and noise characteristics were evaluated and compared with those of reference metallic propellers under Mach-scaled self-propulsion conditions. The results showed that the composite propellers achieved delayed cavitation inception and reduced noise levels compared with the metallic propellers. This improvement suggests that load-induced dynamic deformation enhances both cavitation and noise performance. Furthermore, this study also demonstrates that conventional cavitation assessment methods developed for rigid metallic propellers are not adequate for composite propellers and that Mach number scaling is essential for their reliable evaluation.