In this study an attempt has been made to study the hydrodynamic performance of pumpjet propulsor. Numerical investigation based on the Reynolds Averaged Navier–Stokes (RANS) computational fluid dynamics (CFD) method has been carried out. The structured grid and SST k–ω turbulence model have been applied. The numerical simulations of open water performance of marine propeller E779A are carried out with different advance ratios to verify the numerical simulation method. Results show that the thrust and the torque are in good agreements with experimental data. The grid independent inspection is applied to verify accuracy of numerical simulation grid. The numerical predictions of hydrodynamic performance of pumpjet propulsor are carried out with different advance ratios. Results indicate that the rotor provides the main thrust of propulsor and the balance performance of propulsor is generally satisfactory. Additionally, the curve of propulsor efficiency is in good agreement with experimental data. Furthermore, the pressure distributions around rotor and stator blades are reasonable. Beyond that, the existence of tip clearance accounts for the appearance of tip vortex that leads to a further loss in efficiency and a probability of cavitation phenomenon

Numerical simulation based on the Reynolds Averaged Navier–Stokes (RANS) Computational Fluid Dynamics (CFD) method had been carried out with the commercial code ANSYS CFX. The structured grid and SST k–ω turbulence model had been adopted. The impact of non-condensable gas (NCG) on cavitation performance had been introduced into the Schnerr and Sauer cavitation model. The numerical investigation of cavitating flow of marine propeller E779A was carried out with different advance ratios and cavitation numbers to verify the numerical simulation method. Tip clearance effects on the performance of pumpjet propulsor had been investigated. Results showed that the structure and characteristics of the tip leakage vortex and the efficiency of the propulsor dropped more sharply with the increase of the tip clearance size. Furthermore, the numerical simulation of tip clearance cavitation of pumpjet propulsor had been presented with different rotational speed and tip clearance size. The mechanism of tip clearance cavitation causing a further loss of the efficiency had been studied. The influence of rotational speed and tip clearance size on tip clearance cavitation had been investigated

A detailed analysis of the characteristics and stability of the trajectory of a high-speed projectile during water entry is investigated numerically. The Zwart–Gerber–Belamri cavitation model and the shear stress transport k–ω turbulence model based on the Reynolds-averaged Navier–Stokes method are employed. The numerical method is validated by comparison of its results with the experimental images of cavity shape and with measurements of the penetration distance. Using this numerical method, the influences of rotational speed, initial velocity, and water-entry angle of the projectile on the stability and characteristics of its trajectory are investigated. The variations in projectile trajectory, total drag, and velocity reduction are analyzed. In addition, the cavity characteristics at water entry are presented and analyzed. The results show that the rotation of the projectile has an adverse influence on the stability at water entry, although the magnitude of the rotational speed has little effect on the reduction in projectile velocity. The initial velocity of the projectile has a direct effect on the trajectory stability. It is also found that in practice, there should be a critical water-entry angle for the stability of a projectile.