Transient numerical study of projectiles undergoing cavitating flows

• Main Author: Yeo, Jovan Rui
• Other Authors: New Tze How, Daniel
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Mechanical engineering::Fluid mechanics
• Online Access: https://hdl.handle.net/10356/167289
• Institution: Nanyang Technological University

Supercavitation is a phenomenon when a gas or vapor pocket fully encloses a body travelling through a liquid medium. There are substantial benefits to be reaped such as eliminating skin friction drag entirely. However, the effect of a projectile’s geometry on the behavior of the cavitation pocket is not well understood, and understanding the generation and decay of the pocket would be useful in further development of such projectiles. Using the commercial Computational Fluid Dynamics (CFD) software Ansys Fluent, multiple flow simulations were performed after determining the optimal mesh parameters. The key finding is that the projectile that had a conical nosecone over a cylindrical body had the lowest total drag while still being able to completely cover the body in a cavitation pocket among the geometries tested under the set flow parameters. The results are expected to differ under different flow parameters. Despite what is stated in literature, no cyclic shedding behavior was noted to occur. A suspected reason is the lack of refinement of the determined mesh parameters that were deemed suitable from steady-state tests but were not able to fully resolve the liquid-vapor interface where the instabilities that lead to pocket collapse are expected to occur. However, enough data was gained to serve as a guideline for future design work involving cavitators of these geometries.