Effect of gas cavity size and eccentricity on shock interaction with a cylinder at near-critical conditions

In this study, we investigate the impact of gas cavity size and eccentricity on the interaction of shockwaves with a cavity-embedded fuel-liquid cylinder under near-critical conditions. We analyze a range of scenarios involving both eccentric and concentric cavities, varying cavity radii (0-0.875R), eccentricity angles (0°–180°), and distances (0R-0.45R). Our methodology entails modeling the evolution of the fuel cylinder and surrounding gas flow using compressible multi-component equations, employing a finite-volume-based hybrid numerical framework capable of accurately capturing shocks and interfaces. Additionally, real-fluid thermodynamic relationships are employed, validated against reference data, showing excellent agreement. Mesh independence studies are provided. We analyze the shock impingement characteristics, deformation of the cylinder and cavity, and the formation of vortices. Various phenomena at different evolution stages are explored, including wave pattern evolution, jet formation, cavity breakup, baroclinic vorticity distribution, and circulation histories. Size and eccentricity of the cavity determine time intervals between wave contact with the cylinder and with the cavity, thereby influencing the evolution of wave patterns and interface deformation. We propose an analytical model for deposited circulation, obtained by appropriately combining the Yang, Kubota, and Zukoski (YKZ) and the Zhang and Zou (ZZ) models, which agrees well with numerical findings for cases involving smaller cavities. However, for larger cavities, as the cavity gradually reaches the cylinder surface, induced coupling effects invalidate the model. Furthermore, we introduce four predictive fits for the center-of-mass position of the shocked cylinder under near-critical conditions. These fits—the Time-Size Polynomial Prediction Fit, the Time-Eccentricity Polynomial Prediction Fit, the Time-Eccentricity Distance Polynomial Prediction Fit, and the Connecting Rod Prediction Fit—are tailored for cases involving cavities of varying sizes, eccentricity angles, and distances. Demonstrating good predictive performance, these fits offer valuable insights into the mixing behavior of liquid fuel sprays in a diverse range of near-critical environments and high-speed propulsion systems.     «

In this study, we investigate the impact of gas cavity size and eccentricity on the interaction of shockwaves with a cavity-embedded fuel-liquid cylinder under near-critical conditions. We analyze a range of scenarios involving both eccentric and concentric cavities, varying cavity radii (0-0.875R), eccentricity angles (0°–180°), and distances (0R-0.45R). Our methodology entails modeling the evolution of the fuel cylinder and surrounding gas flow using compressible multi-component equations, emp...     »