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Investigate the Oscillations and Parameters of Bubble Induced by Laser in the Prescence of Acoustic Field

Razeghi, Fatemeh | 2011

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 42708 (04)
  4. University: Sharif University of Technology
  5. Department: Physics
  6. Advisor(s): Sadighi-Bonabi, Rasoul
  7. Abstract:
  8. Sonoluminescence is called a phenomenon in which a gas bubble is trapped in an antinode of a pressure field by a driven periodic acoustical field in a fluid and oscillations and at the end of each collapse, emits a flash. For this emission various conditions for stability must be satisfied, like diffusion stability, shape stability and positional stability. Another method to produce the bubbles is applications of a focused laser beam. In this method, a laser pulse is focused into a transparent buffer liquid like water and bubbles which are induced by the laser are so called Laser Induced Single Cavitation Bubble Luminescence (LI-SCBL). In the presence of the laser, the fluid acts as acompressible one and changes the bubble dynamics equations. In this thesis, the quasi-adiabatic model is used to study the fluctuation of a single bubble induced by laser in the presence of the acoustic field. By using this model, the complete cycle of bubble movement is represented for LI-SCBL in the presence of the acoustic field. Based on the mentioned model, some important bubble parameters such as interior pressure and temperature are investigated. By comparing the obtained results for LI-SCBL in the presence of the acoustic field, it is found that the maximum bubble radius is about ten times larger than the ones for the SBSL. A comparison is made between parameters such as bubble radius, interior temperature and pressure of the bubble induced by laser and acoustic field influenced by different driving pressure amplitudes. It is found that, by increasing the driving pressure amplitude, the bubble radius decrease in both cases, however, the bubble interior pressure and temperature increase. It should be realized that the consistency of these results for LI-SCBL in the presence of the acoustic field with the reported experimental observation for the maximum bubble radius and the maximum interior temperature in the collapse time indicates the reliability of this method for the other mentioned calculated parameters
  9. Keywords:
  10. Rayleigh-Plesset Equation ; Shock Wave ; Blackbody Radiation ; Bremsstrahlung Radiation ; Sonoluminescence

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