Structural characteristics of a cavera at a small bubble stage of cavitation
Abstract
The article considers shock pulses arising from the closure of bubbles, depending on the structure of the cavitation cavity. Since the finely bubbly stage of cavitation is usually observed on the elements of hydraulic structures, the structural characteristics of the three stages of the appearance of cavitation are further investigated. Studies of the structure of cavitation require fixing the spatial pattern of the bubble zone. This is due to the need to use high-intensity luminous flux with ultra-short exposure. To solve these problems, a holography method using a ruby laser was used. To study the kinematics of a bubble near a wall, a ruby laser operated in the free-running mode during pumping with a duration of a total radiation pulse of up to 500 µs. Such a duration allows using a passive shutter to obtain up to three short light pulses (30 - 40 µs) of modulated Q-factor. The time intervals between pulses are measured on the screen of the storage oscilloscope and amount to 20 - 100 µs. The light pulse is transmitted to the oscilloscope by a coaxial photocell 30 FEK - 09.