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The photoacoustic effect generated by an incompressible sphere
Gerald J Diebold1, Andrew C Beveridge, Theron J Hamilton
1Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA. gerald_diebold@brown.edu
The Journal of the Acoustical Society of America
|November 15, 2002
Summary
A sphere in fluid generates photoacoustic waves when heated by light. The study reveals how heat release speed affects the acoustic wave, impacting its profile and characteristics.
Area of Science:
- Acoustics
- Thermodynamics
- Optics
Background:
- Photoacoustic effect generation in fluids.
- Heat diffusion dynamics in incompressible spheres.
- Acoustic wave propagation principles.
Purpose of the Study:
- Investigate photoacoustic effect properties for an incompressible sphere.
- Analyze the influence of heat liberation rate on acoustic wave generation.
- Characterize acoustic wave profiles based on heat release dynamics.
Main Methods:
- Utilizing Green's function solution for the wave equation.
- Applying Neumann boundary conditions for pressure.
- Analyzing heat diffusion and thermal expansion dynamics.
Main Results:
- Fast heat liberation produces an outgoing compressive pulse followed by a reflected pulse.
- Frequency-dependent reflection modifies the time profile of the reflected acoustic wave.
- Slow heat release results in a photoacoustic effect proportional to the heat flux derivative.
Conclusions:
- The photoacoustic effect in spheres is sensitive to heat release rates.
- Acoustic wave characteristics are predictable based on thermal and physical properties.
- This research provides insights into photoacoustic wave generation and modification.