In this paper,we present a conservative semi-Lagrangian scheme designed for the numeri-cal solution of 3D hydrostatic free surface flows involving sediment transport on unstruc-tured Voronoi meshes.A high-order recons...In this paper,we present a conservative semi-Lagrangian scheme designed for the numeri-cal solution of 3D hydrostatic free surface flows involving sediment transport on unstruc-tured Voronoi meshes.A high-order reconstruction procedure is employed for obtaining a piecewise polynomial representation of the velocity field and sediment concentration within each control volume.This is subsequently exploited for the numerical integration of the Lagrangian trajectories needed for the discretization of the nonlinear convective and viscous terms.The presented method is fully conservative by construction,since the transported quantity or the vector field is integrated for each cell over the deformed vol-ume obtained at the foot of the characteristics that arises from all the vertexes defining the computational element.The semi-Lagrangian approach allows the numerical scheme to be unconditionally stable for what concerns the advection part of the governing equations.Furthermore,a semi-implicit discretization permits to relax the time step restriction due to the acoustic impedance,hence yielding a stability condition which depends only on the explicit discretization of the viscous terms.A decoupled approach is then employed for the hydrostatic fluid solver and the transport of suspended sediment,which is assumed to be passive.The accuracy and the robustness of the resulting conservative semi-Lagrangian scheme are assessed through a suite of test cases and compared against the analytical solu-tion whenever is known.The new numerical scheme can reach up to fourth order of accu-racy on general orthogonal meshes composed by Voronoi polygons.展开更多
In a recently published study in Science,Naòn et al.report two uncharacterized splice variants of Mitofusin 2(MFN2)that specifically shape and tether the endoplasmic reticulum(ER)to mitochondria.1 This work sheds...In a recently published study in Science,Naòn et al.report two uncharacterized splice variants of Mitofusin 2(MFN2)that specifically shape and tether the endoplasmic reticulum(ER)to mitochondria.1 This work sheds new light on the pleiotropic effects previously ascribed to MFN2 loss-of-function mutations,and has important implications for associated metabolic and neurological diseases.展开更多
基金support of MIUR-PRIN Project 2017,No.2017KKJP4X“Innovative numerical methods for evolutionary partial differential equations and applications”.
文摘In this paper,we present a conservative semi-Lagrangian scheme designed for the numeri-cal solution of 3D hydrostatic free surface flows involving sediment transport on unstruc-tured Voronoi meshes.A high-order reconstruction procedure is employed for obtaining a piecewise polynomial representation of the velocity field and sediment concentration within each control volume.This is subsequently exploited for the numerical integration of the Lagrangian trajectories needed for the discretization of the nonlinear convective and viscous terms.The presented method is fully conservative by construction,since the transported quantity or the vector field is integrated for each cell over the deformed vol-ume obtained at the foot of the characteristics that arises from all the vertexes defining the computational element.The semi-Lagrangian approach allows the numerical scheme to be unconditionally stable for what concerns the advection part of the governing equations.Furthermore,a semi-implicit discretization permits to relax the time step restriction due to the acoustic impedance,hence yielding a stability condition which depends only on the explicit discretization of the viscous terms.A decoupled approach is then employed for the hydrostatic fluid solver and the transport of suspended sediment,which is assumed to be passive.The accuracy and the robustness of the resulting conservative semi-Lagrangian scheme are assessed through a suite of test cases and compared against the analytical solu-tion whenever is known.The new numerical scheme can reach up to fourth order of accu-racy on general orthogonal meshes composed by Voronoi polygons.
基金supported by the Deutsche Forschungsgemeinschaft(SFB1218-Grant No.269925409 and CECAD EXC 2030-Grant No.390661388 to E.M.and M.B.,SFB1451-Grant No.431549029 to M.B.).
文摘In a recently published study in Science,Naòn et al.report two uncharacterized splice variants of Mitofusin 2(MFN2)that specifically shape and tether the endoplasmic reticulum(ER)to mitochondria.1 This work sheds new light on the pleiotropic effects previously ascribed to MFN2 loss-of-function mutations,and has important implications for associated metabolic and neurological diseases.
