A direct boundary element method (BEM) has been studied in the paper based on a set of sufficient and necessary boundary integral equations (BIE) for the plane harmonic functions. The new sufficient and necessary BEM ...A direct boundary element method (BEM) has been studied in the paper based on a set of sufficient and necessary boundary integral equations (BIE) for the plane harmonic functions. The new sufficient and necessary BEM leads to accurate results while the conventional insufficient BEM will lead to inaccurate results when the conventional BIE has multiple solutions. Theoretical and numerical analyses show that it is beneficial to use the sufficient and necessary BEM, to avoid hidden dangers due to non-unique solution of the conventional BIE.展开更多
This paper examines the characteristics of a harmonic plane wave in 1D and applies it to a model of an auditorium in the shape of a quarter of an ellipsoid. In the application, this paper will mainly look at transmiss...This paper examines the characteristics of a harmonic plane wave in 1D and applies it to a model of an auditorium in the shape of a quarter of an ellipsoid. In the application, this paper will mainly look at transmission loss, reverberation, disruption of the performers, and differences between different frequencies. The differences between different frequencies will be analyzed on both a macroscopic auditorium level as well as on a microscopic level of a single point in the audience.展开更多
Ghasemzadeh and Abounouri[1]developed a mathematical model of partially saturated soils that is solved using the potential method,which decomposes elastodynamics equations into two standard wave equations,a scalar wav...Ghasemzadeh and Abounouri[1]developed a mathematical model of partially saturated soils that is solved using the potential method,which decomposes elastodynamics equations into two standard wave equations,a scalar wave equation for scalar potential and a vector wave equation for vector potential.In such a medium,four waves exist three longitudinal and one shear.Each fluid phase tortuous path is taken into account in this model.The inertial coupling between solid and fluid particles is consid-ered.Furthermore,both open-pore and sealed-pore boundaries are explored to investigate the reflection phenomenon at the surface of partially saturated soils.For both boundaries,the reflection coefficients of inhomogeneous waves at a partially saturated soil surface are found as a non-singular set of linear equations.All waves(both reflected and incident)in partially saturated soils are pronounced as inhomogeneous due to viscosity in pore fluids(i.e.,distinct directions of attenuation and propagation).The energy shares of reflected waves are determined using an energy matrix.A numerical example is used to determine the reflection coefficients and the distribution of incident energy among the various reflected waves.The effect of different physical features on reflection coefficients and incident energy partitioning is illustrated graphically.The conservation of incident energy at the surface of partially saturated soils is mathematically confirmed at all angles of incidence.展开更多
文摘A direct boundary element method (BEM) has been studied in the paper based on a set of sufficient and necessary boundary integral equations (BIE) for the plane harmonic functions. The new sufficient and necessary BEM leads to accurate results while the conventional insufficient BEM will lead to inaccurate results when the conventional BIE has multiple solutions. Theoretical and numerical analyses show that it is beneficial to use the sufficient and necessary BEM, to avoid hidden dangers due to non-unique solution of the conventional BIE.
文摘This paper examines the characteristics of a harmonic plane wave in 1D and applies it to a model of an auditorium in the shape of a quarter of an ellipsoid. In the application, this paper will mainly look at transmission loss, reverberation, disruption of the performers, and differences between different frequencies. The differences between different frequencies will be analyzed on both a macroscopic auditorium level as well as on a microscopic level of a single point in the audience.
文摘Ghasemzadeh and Abounouri[1]developed a mathematical model of partially saturated soils that is solved using the potential method,which decomposes elastodynamics equations into two standard wave equations,a scalar wave equation for scalar potential and a vector wave equation for vector potential.In such a medium,four waves exist three longitudinal and one shear.Each fluid phase tortuous path is taken into account in this model.The inertial coupling between solid and fluid particles is consid-ered.Furthermore,both open-pore and sealed-pore boundaries are explored to investigate the reflection phenomenon at the surface of partially saturated soils.For both boundaries,the reflection coefficients of inhomogeneous waves at a partially saturated soil surface are found as a non-singular set of linear equations.All waves(both reflected and incident)in partially saturated soils are pronounced as inhomogeneous due to viscosity in pore fluids(i.e.,distinct directions of attenuation and propagation).The energy shares of reflected waves are determined using an energy matrix.A numerical example is used to determine the reflection coefficients and the distribution of incident energy among the various reflected waves.The effect of different physical features on reflection coefficients and incident energy partitioning is illustrated graphically.The conservation of incident energy at the surface of partially saturated soils is mathematically confirmed at all angles of incidence.
