Strong velocity scale effect on cavitation for orifice tunnels was revealed through comparing the results of model tests in vacuum tanks and that of prototype measurements at construction site. A new formula predicting incipient cavitation number of orifice rings is presented in this paper. The predicted data for the prototype scale are coincident well with the prototype measured one.

This paper presents experimental data and numerical simulations of transient vaporous cavitation events generated by a downstream fast valve closure in a pipeline. The experimental apparatus comprises a 37.2 m long constant-sloping pipe of 22.1 mm internal diameter connecting two pressurized tanks. The simulation results show that improper selection of the weighting function in the convolution-...

The direct numerical simulation (DNS) method has been used to the study of the linear and shock wave propagation in bubbly fluids and the estimation of the efficiency of the cavitation mitigation in the container of the Spallation Neutron Source liquid mercury target. The DNS method for bubbly flows is based on the front tracking technique developed for free surface flows. Our front tracking hy...

Focusing on the tip leakage vortex cavitation, experimental and numerical studies were carried out as the first step of the investigation of cavitations in tip leakage flow. For a single hydrofoil with a tip clearance, tip leakage vortex cavitations were observed for various cavitation numbers and angles of attack. To simulate the tip leakage vortex cavitation, a simple calculation of 2-D unste...

Cavitation associated with the impact of a sphere on a flat surface is investigated using high-speed photography. The sphere, of diameter 15 or 45 mm and made from Ertacetal or stainless steel, was fully submerged and accelerated using a spring-loaded mechanism to achieve Reynolds numbers based on impact velocity and sphere radius of up to 7.2×10. The static pressure and impact velocity were va...

The structure of the pressure field of a turbulent water flow between counter-rotating disks is studied using cavitation. The flow is seeded with microscopic gas bubbles and the hydrostatic pressure is reduced until large negative pressure fluctuations trigger cavitation. Cavitation is detected via light scattering from cavitating bubbles. The spatial structure of the low-pressure events are vi...

In many cavitating liquid flows, when the number and concentration of the bubbles exceeds some critical level, the flow becomes unsteady and large clouds of cavitating bubbles are periodically formed and then collapse when convected into regions of higher pressure. This phenomenon is known as cloud cavitation and when it occurs it is almost always associated with a substantial increase in the c...

Abstract This paper, aiming at the water-exit process of vehicle with cavitation, based on moving domain method coupled SDOF (six degrees freedom) solver, using VOF (volume fluid) multiphase model and Schnerr-Sauer cavitation model, carrying out numerical simulation research multi-conditions. Comparing vertical launch vehicles different Ca (cavitation number) cases, sudden decrease in number is...

The shedding process of the Kármán vortices at the trailing edge of a 2D hydrofoil at high Reynolds numbers is investigated. The focus is put on the effect of the cavitation on the vortex street morphology. A direct insight is also provided on the role of the structural vibration on the cavitation inception. The shedding frequency, derived from the measurement of flow induced vibration, is foun...