Wing Sections for Hydrofoils—Part 3: Experimental Verifications

Abstract

Lifting surfaces such as hydrofoil wings or propeller blades will encounter periodic variations in angle of attack when operated in waves or in nonuniform ship wakes. Undesirable leading-edge sheet cavitation is a common occurrence on hydrofoils and marine propellers. To effectively avoid or delay leading-edge sheet cavitation it is necessary to develop a lifting surface able to tolerate large variations in angle of attack without cavitation. Based on a profile design theory, a series of hydrofoil sections having large cavitation-free bucket widths was developed and presented in previous papers, Part 1 and Part 2. The present paper provides the experimental verification. Profile YS-920 was selected as representative of the series and was tested in a high-speed water tunnel. The measured cavitation inception characteristics and force data of YS-920 were compared with the theoretical predictions. Additionally, they were compared with the measured cavitation and force data of the widely used NACA 66 (MOD) and NACA 16–309 wing sections to show the advantages of using a newly developed hydrofoil section to delay or avoid cavitation.