Acoustic radiation force and torque on suspended objects in an inviscid fluid

Detalhes bibliográficos
Ano de defesa: 2014
Autor(a) principal: Andrade, José Henrique Araújo Lopes de
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Tese
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal de Alagoas
Brasil
Programa de Pós-Graduação em Física da Matéria Condensada
UFAL
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://www.repositorio.ufal.br/handle/riufal/1694
Resumo: Recent advances and interest in ultrasound particle manipulation calls for theoretical understanding of acoustic radiation force and torque exerted on a configuration of multiple particles. In this thesis we theoretically study the acoustic radiation force and torque exerted by an arbitrary acoustic beam on a cluster of spherical particles in an inviscid fluid. The method is based on the partial-wave expansion (PWE) and the translational addition theorem for spherical wave functions. The combination of (PWE) and addition theorem Method enable us to solve the associated multiple scattering problem by numerically computing the (PWE) coefficients in a system of linear equations. On the other hand, when we consider the radiation force and torque exerted on a single sphere, the addition theorem has the advantage to solve this problem in a closed form. After obtaining the PWE coefficients, the acoustic radiation force and torque is computed through the farfield series solution. To illustrate the method, the acoustic radiation force and torque exerted on a single or multiple spheres are analyzed. In the case of a single sphere, the force is generated by a spherically focused ultrasound beam, where as the torque is generated by a Bessel vortex beam. For the multiple spheres configuration, the radiation force is induced by a traveling and a standing plane wave. In a specific configuration of three olive oil droplets suspended in water, with radii of the order of the wavelength, we found that rescattering events produce an acoustic interaction force, which significantly changes the radiation force on each droplet depending on the inter-droplet distance. In addition, we have found for the first time that an acoustic interaction torque due to the nonsymmetric spatial distribution of the acoustic energy density to the droplets. Further more, our study does not have restrictions on the spheres size compared to the wave length, nor on their composition material, which includes rigid, void, compressional liquid, elastic and viscoelastic solids, and layered material. Finally, this study has direct applications on methods for noncontact object handling by acoustic waves such as acoustic levitation, acoustical tweezers, and acoustophoresis in lab-on-a-chip devices.