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Title: Hydrodynamic, acoustic, and electrical characteristics of underwater spark discharges initiated by different mechanisms
Author: Sun, Ying
ISNI:       0000 0004 7431 490X
Awarding Body: University of Strathclyde
Current Institution: University of Strathclyde
Date of Award: 2018
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Underwater spark discharge is one of the most common methods to generate intense acoustic impulses in water for different purposes in practical applications. As compared with chemical explosion, the underwater spark discharges provide a number of advantages: they do not generate toxic compounds or species, no high explosives involved and they provide high degree of controllability. These features have led to a large number of studies of underwater spark discharge mechanisms and their potential practical utilisation. This work is aimed at experimental investigation of the breakdown characteristics of underwater spark discharges with three different initiation mechanisms: free discharge, air-bubble-stimulated discharge and wire-guided discharge. Study on the electrical and acoustic parameters of the discharge process has conducted. A capacitive voltage impulse system was developed to energise three different electrode topologies. Acoustic and electrical parameters of underwater spark discharges were obtained from experimental results, such as acoustic magnitude, period of cavity oscillation, breakdown voltage, plasma resistance and energy delivered into the plasma channel. Phenomenological scaling relations were established for these parameters, which allowed for better understanding and prediction of the acoustic performance of underwater spark discharges. An analytical model, which describes the cavity oscillation, has been developed and comparison of the modelling and experimental results was conducted for all three types of discharges. This model allowed for accurate description of the time-dependent behaviour of different parameters during the underwater spark discharge process. The obtained results are important for optimising the circuit parameters for generation of tailored acoustic impulses for different practical applications.
Supervisor: Timoshkin, Igor Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral