Abstract
Propagation of pressure disturbances in aerosol with suspended liquid or
solid particles is commonly encountered in an extensive range of physical
scenarios, from environmental study of atmospheric aerosols to engineering
applications of using suspended aerosol particles to reduce noise created by
jet engines. Understanding the interphase interactions between the pressure
waveforms and the suspended particles therefore provides useful
explanations in many environmental and engineering related phenomena.
Early studies of aerosol acoustics have contributed some insights on how a
passage of pressure wave loses its energy with the suspended particles via
thermal and momentum exchanges.
The development mathematical models of aerosol acoustics faces two
main challenges. First, when the disturbance is of a moderate or high
amplitude, the assumptions used in linear acoustics are not applicable due to
the fact that, higher amplitude waveforms suffer from the wave distortion
that may advance into shock formations. Second, the variations in particle
materials, sizes and distributions cause the interphase thermal and
momentum relaxations to occur at different rates. Such aerosols are referred
to as polydispersed aerosols. To this end, this thesis proposed a
comprehensive mathematical model of finite-amplitude pressure wave
propagating in polydispersed aerosols. From this model, a numerical method
based on MacCormack finite-difference discretization is developed to
simulate the propagation of the waveforms. Detailed parametric studies are
performed and the obtained results show the effects of various aerosol and
wave parameters on the evolution and energy dissipation of the waveforms
solid particles is commonly encountered in an extensive range of physical
scenarios, from environmental study of atmospheric aerosols to engineering
applications of using suspended aerosol particles to reduce noise created by
jet engines. Understanding the interphase interactions between the pressure
waveforms and the suspended particles therefore provides useful
explanations in many environmental and engineering related phenomena.
Early studies of aerosol acoustics have contributed some insights on how a
passage of pressure wave loses its energy with the suspended particles via
thermal and momentum exchanges.
The development mathematical models of aerosol acoustics faces two
main challenges. First, when the disturbance is of a moderate or high
amplitude, the assumptions used in linear acoustics are not applicable due to
the fact that, higher amplitude waveforms suffer from the wave distortion
that may advance into shock formations. Second, the variations in particle
materials, sizes and distributions cause the interphase thermal and
momentum relaxations to occur at different rates. Such aerosols are referred
to as polydispersed aerosols. To this end, this thesis proposed a
comprehensive mathematical model of finite-amplitude pressure wave
propagating in polydispersed aerosols. From this model, a numerical method
based on MacCormack finite-difference discretization is developed to
simulate the propagation of the waveforms. Detailed parametric studies are
performed and the obtained results show the effects of various aerosol and
wave parameters on the evolution and energy dissipation of the waveforms
Original language | English |
---|---|
Qualification | Ph.D. |
Awarding Institution |
|
Award date | 20 Apr 2024 |
Publication status | Published - Sept 2016 |