Water Entry of Hypervelocity Projectiles
Abstract
The purpose of this action is to add FY23 CR#1 YIP funds, in the amount of $50,000.00, for a new YIP Grant award with Case Western Reserve University. GRANT13670222 is applicable.--Water Entry of Hypervelocity ProjectilesProject AbstractApproved for Public ReleaseThe overall objective of this proposal is to investigate the complex physics of the entry of a high speed projectile into water, where the velocity is supersonic relative to the speed of sound in water, i.e., greater than 1.5 km/s. High speed water entry events feature a combination of fluid and thermodynamic phenomena of interest to the US Navy that are very challenging to model, including propagating underwater shock and rarefaction waves, the formation and closure of a cavity of entrained air in the wake of the projectile, and water cavitation. We will characterize the flow created by the entry of spherical projectiles at speeds greater than 2 km/s by measuring several important quantities, such as the shock speed, cavity shape and size, shock and cavitation pressures, and drag on the projectile, by using high speed imaging and pressure transducers, each with temporal resolution greater than 1 MHz. The imaging will primarily consist of simultaneous direct-illumination imaging and background oriented schlieren (BOS). Experiments will be performed with the Hypervelocity Projectile LightGas Gun (HOPLITE), which is a powder-driven, 2-stage light gas gun to be constructed by Physics Applications Inc. at Case Western Reserve University (CWRU). Experiments will be complemented by modeling with the CTH hydrocode in collaboration with the Naval Surface Warfare Center (NSWC), Carderock Division. Our research objectives are:- Objective 1: Study the effects of impact velocity on the water entry flow features from 1 to 4 km/s in experiments using the HOPLITE.- Objective 2: Model supersonic water entry using the CTH hydrocode and validate predictions of pressures, wave propagation, and cavitation with experiments.- Objective 3: Study the water entry of projectiles that fragment on impact experimentally.The impact of this research will include the first published experimental data of projectilewater impacts at speeds greater than 1.5 km/s. This will provide much-needed information for modelers at NSWC centers, particularly for multi-phase and multi-physics problems related to hypersonic systems and explosives in maritime environments. Furthermore, we will develop a deeper fundamental understanding of pressure wave propagation and interactions, cavity formation and closure, and cavitation in high speed liquid flows.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 12, 2023
- Source ID
- N000142312048
Entities
People
- Bryan Schmidt
Organizations
- Case Western Reserve University
- Office of Naval Research
- United States Navy