Antiplane response of two scalene triangular hills and a semi-cylindrical canyon by SH-waves is studied using wave function expansion and complex function method. Firstly, the analytical model is divided into three pa...Antiplane response of two scalene triangular hills and a semi-cylindrical canyon by SH-waves is studied using wave function expansion and complex function method. Firstly, the analytical model is divided into three parts, and the displacement solutions of wave fields are constructed based on boundary conditions in the three regions. Three domains are then conjoined to satisfy the ＂conjunction＂ condition at shared boundary. In addition, combined with the zero-stress condition of semi-cylindrical canyon, a series of infinite algebraic equations for the problem are derived. Finally, numerical examples are provided and the influence of different parameters on ground motion is discussed.展开更多
Scattering of SH-waves on the triangular hill joined by semi-cylindrical canyon in half-space is studied using the method of complex function and moving coordinates. The model being studied is divided into two domains...Scattering of SH-waves on the triangular hill joined by semi-cylindrical canyon in half-space is studied using the method of complex function and moving coordinates. The model being studied is divided into two domains. The wave functions satisfying the required condition at each wedge are constructed in each equation. The equations are solved with Fourier expansion. Numerical results are provided to discuss the influence of scattering of SH-waves.展开更多
Fully resolved numerical simulations of a micron-sized spherical particle residing on a surface with large-scale roughness are performed by using the Lattice-Boltzmann method.The aim is to investigate the influence of...Fully resolved numerical simulations of a micron-sized spherical particle residing on a surface with large-scale roughness are performed by using the Lattice-Boltzmann method.The aim is to investigate the influence of surface roughness on the detachment of fine drug particles from larger carrier particles for transporting fine drug particles in a DPI(dry powder inhaler).Often the carrier surface is modified by mechanical treatments for modifying the surface roughness in order to reduce the adhesion force of drug particles.Therefore,drug particle removal from the carrier surface is equivalent to the detachment of a sphere from a rough plane surface.Here a sphere with a diameter of 5μm at a particle Reynolds number of 1.0,3.5 and 10 are considered.The surface roughness is described as regularly spaced semi-cylindrical asperities(with the axes oriented normal to the flow direction)on a smooth surface.The influence of asperity distance and size ratio(i.e.the radius of the semi-cylinder to the particle radius,Rc/Rd)on particle adhesion and detachment are studied.The asperity distance is varied in the range 1.2<L/Rd<2 and the semi-cylinder radius between 0.5<Rc/Rd<0.75.The required particle resolution and domain size are appropriately selected based on numerical studies,and a parametric analysis is performed to investigate the relationship between the contact distance(i.e.half the distance between the particle contact points on two neighbouring semi-cylinders),the asperity distance,the size ratio,and the height of the particle centroid from the plane wall.The drag,lift and torque acting on the spherical particle are measured for different particle Reynolds numbers,asperity distances and sizes or diameters.The detachment of particles from rough surfaces can occur through lift-off,sliding and rolling,and the corresponding detachment models are constructed for the case of rough surfaces.These studies will be the basis for developing Lagrangian detachment models that eventually should allow the optimisation of dry powder inhaler performance through computational fluid dynamics.展开更多
基金Natural Science Foundation of Heilongjiang Province,China under Grant No.A201310the Scientific Research Starting Foundation for Post Doctorate of Heilongjiang Province,China under Grant No.LBH-Q13040
文摘Antiplane response of two scalene triangular hills and a semi-cylindrical canyon by SH-waves is studied using wave function expansion and complex function method. Firstly, the analytical model is divided into three parts, and the displacement solutions of wave fields are constructed based on boundary conditions in the three regions. Three domains are then conjoined to satisfy the ＂conjunction＂ condition at shared boundary. In addition, combined with the zero-stress condition of semi-cylindrical canyon, a series of infinite algebraic equations for the problem are derived. Finally, numerical examples are provided and the influence of different parameters on ground motion is discussed.
文摘Scattering of SH-waves on the triangular hill joined by semi-cylindrical canyon in half-space is studied using the method of complex function and moving coordinates. The model being studied is divided into two domains. The wave functions satisfying the required condition at each wedge are constructed in each equation. The equations are solved with Fourier expansion. Numerical results are provided to discuss the influence of scattering of SH-waves.
基金supported by the Chinese Fundamental Research Funds for the Central Universities of the project No.2020kfyXJJS065.
文摘Fully resolved numerical simulations of a micron-sized spherical particle residing on a surface with large-scale roughness are performed by using the Lattice-Boltzmann method.The aim is to investigate the influence of surface roughness on the detachment of fine drug particles from larger carrier particles for transporting fine drug particles in a DPI(dry powder inhaler).Often the carrier surface is modified by mechanical treatments for modifying the surface roughness in order to reduce the adhesion force of drug particles.Therefore,drug particle removal from the carrier surface is equivalent to the detachment of a sphere from a rough plane surface.Here a sphere with a diameter of 5μm at a particle Reynolds number of 1.0,3.5 and 10 are considered.The surface roughness is described as regularly spaced semi-cylindrical asperities(with the axes oriented normal to the flow direction)on a smooth surface.The influence of asperity distance and size ratio(i.e.the radius of the semi-cylinder to the particle radius,Rc/Rd)on particle adhesion and detachment are studied.The asperity distance is varied in the range 1.2<L/Rd<2 and the semi-cylinder radius between 0.5<Rc/Rd<0.75.The required particle resolution and domain size are appropriately selected based on numerical studies,and a parametric analysis is performed to investigate the relationship between the contact distance(i.e.half the distance between the particle contact points on two neighbouring semi-cylinders),the asperity distance,the size ratio,and the height of the particle centroid from the plane wall.The drag,lift and torque acting on the spherical particle are measured for different particle Reynolds numbers,asperity distances and sizes or diameters.The detachment of particles from rough surfaces can occur through lift-off,sliding and rolling,and the corresponding detachment models are constructed for the case of rough surfaces.These studies will be the basis for developing Lagrangian detachment models that eventually should allow the optimisation of dry powder inhaler performance through computational fluid dynamics.
