Pseudo-Gaussian cylindrical acoustical beam – Axial scattering and radiation force on an elastic cylinder

Autor: Mitri, F.G., Fellah, Z.E.A., Silva, G.T.
Přispěvatelé: Fellah, Zine El Abiddine, Los Alamos Natl Lab, MPA-11, Sensors & Electrochemical Devices, Acoustics & Sensors Technology Team, Ondes et Imagerie (O&I), Laboratoire de Mécanique et d'Acoustique [Marseille] (LMA ), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Universidade Federal de Alagoas = Federal University of Alagoas (UFAL), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)
Jazyk: angličtina
Rok vydání: 2014
Předmět:
Zdroj: Journal of Sound and Vibration
Journal of Sound and Vibration, 2014, 333 (26), pp.7326-7332
Journal of Sound and Vibration, Elsevier, 2014, 333 (26), pp.7326-7332
ISSN: 0022-460X
1095-8568
Popis: International audience; a b s t r a c t Making use of the addition theorem for the cylindrical wave functions and the complex-source-point method in cylindrical coordinates, an exact solution to the Helmholtz equation is derived, which corresponds to a tightly focused (or collimated) cylindrical quasi-Gaussian beam with arbitrary waist. The solution is termed "quasi-Gaussian" to make a distinction from the standard Gaussian beam solution obtained in the paraxial approximation. The advantage of introducing this new solution is the efficient and fast computational modeling of tightly focused or quasi-collimated cylindrical wave-fronts depending on the dimensionless waist parameter kw 0 , where k is the wavenumber of the acoustical radiation. Moreover, a closed-form partial-wave series expansion is obtained for the incident field, which has the property that the axial scattering (i.e. along the direction of wave propagation) and the axial acoustic radiation force (which is a time-averaged quantity) on a cylinder, can be calculated without any approximations in the limit of linear acoustical waves in a nonviscous fluid. Examples are found where the extinction in the radiation force function plot is found to be correlated with conditions giving reduction of the backscattering from an elastic cylinder. Those results are useful in beam-forming design, particle manipulation in acoustic tweezers operating with focused cylindrical beams, and the prediction of the scattering and radiation forces on a cylindrical particle or liquid bridges.
Databáze: OpenAIRE
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