Formation of cylindrical shock and rarefaction waves by SW-loading a bubbly liquid layer with free surface
Compilation
| Language |
Английский |
| Type |
Compilation |
| Pages count |
1 |
| Authors |
Kedrinskiy V.K.
,
Bol'shakova E. E.
|
. The experiments carried out on the formation and collapse of axis-symmetrical empty rupture (cavity) covered by thin layer of micro-bubbles at SW-loading of liquid layer have showed that at the end of the process the collapse of quasi-empty cavity has quasi-onedimensional cylindrical character. In the vicinity of collapse place, when the empty rupture is disappearing, the generation of quasi-onedimensional cylindrical SW, and the formation (by a SW) of a cylindrical hollow vortex ring consisting of cluster of bubbles are observed.
Results. The full statement of problem includes a few steps. First of them : numerical model for formation of cylindrical shock (SW) and rarefaction (RW) waves at SWloading of a liquid layer with a free surface are considered. The liquid states are pure liquid and distilled water containing free micro-bubbles (1.5 µm radius, 10^6 cm^(-3) nuclei density). The SW initiation is performed by the piston (co-axial) giving the pulse of mass velocity as the exponents for maximal amplitudes from 20 to 100 m/s and the constants up to 30 µs . A two-phase mathematical IKW-model (Iordanskiy – Kogarko - Wingaarden) is the system of equation describing average pressure, velocity and density. It includes the state equations and the Rayleigh type equation describing the dynamics of cavitation zone.
For pure water, the distributions of maximal amplitudes both from the piston along the radius for SW and from free surface up to the piston for rarefaction wave (RW) were calculated. The distribution of maximal amplitudes of positive SW and negative RW along the radius appears to be practically symmetric. It was shown, the SW amplitude decreases close asymptotic r ^(-0.72). The increase of RW amplitude during propagation to the piston has a cumulative effect. Beginning from free surface, the volumetric gas concentration increases up to 10^3 initial values (maximum velocity 100 m/s). Note, that the cavitation development behind the RW front essentially changes its parameters and structure.