arXiv subjects

Shigetoshi Yazaki

Publications and source records attributed to Shigetoshi Yazaki.

5 recordsLinked to original sources

arXiv2021

Convergence of a finite difference scheme for the Kuramoto--Sivashinsky equation defined on an expanding circle

This paper presents a finite difference method combined with the Crank--Nicolson scheme of the Kuramoto--Sivashinsky equation defined on an expanding circle (\cite{KUY}), and the existence, uniqueness, and second-order error estimate of the scheme. The equation can be obtained as a perturbation equation from the circle solution to an interfacial equation and can provide guidelines for understanding the wavenumber selection of solutions to the interfacial equation. Our proposed numerical scheme can help with such a mathematical analysis.

math.NA↗

arXiv2021

A simple numerical method for Hele-Shaw type problems by the method of fundamental solutions

Hele-Shaw flows with time-dependent gaps create fingering patterns, and magnetic fluids in Hele-Shaw cells create intriguing patterns.We propose a simple numerical method for Hele-Shaw type problems by the method of fundamental solutions.The method of fundamental solutions is one of the mesh-free numerical solvers for potential problems, which provides a highly accurate approximate solution despite its simplicity.Moreover, combining with the asymptotic uniform distribution method, the numerical method satisfies the volume-preserving property.We use Amano's method to arrange the singular points in the method of fundamental solutions.We show several numerical results to exemplify the effectiveness of our numerical scheme.

math.NA↗

arXiv2012

On a gradient flow of plane curves minimizing the anisoperimetric ratio

We analyze a gradient flow of closed planar curves minimizing the anisoperimetric ratio. For such a flow the normal velocity is a function of the anisotropic curvature and it also depends on the total interfacial energy and enclosed area of the curve. In contrast to the gradient flow for the isoperimetric ratio, we show there exist initial curves for which the enclosed area is decreasing with respect to time. We also derive a mixed anisoperimetric inequality for the product of total interfacial energies corresponding to different anisotropy functions. Finally, we present several computational examples illustrating theoretical results.

math.DG↗

arXiv2010

Evolution of plane curves with a curvature adjusted tangential velocity

We study evolution of a closed embedded plane curve with the normal velocity depending on the curvature, the orientation and the position of the curve. We propose a new method of tangential redistribution of points by curvature adjusted control in the tangential motion of evolving curves. The tangential velocity distributes grid points along the curve not only uniform but also lead to a suitable concentration and/or dispersion depending on the curvature. Our study is based on solutions to the governing system of nonlinear parabolic equations for the position vector, tangent angle and curvature of a curve. We furthermore present a semi-implicit numerical discretization scheme based on the flowing finite volume method. Several numerical examples illustrating capability of the new tangential redistribution method are also presented in this paper.

math.NA↗

arXiv2008

Analytical and numerical aspects on motion of polygonal curves with constant area speed

General area-preserving motion of polygonal curves is formulated as a system of ODEs. Solution polygonal curves belong to a prescribed polygonal class, which is similar to the admissible class used in the crystalline curvature flow. The ODEs are discretized implicitly in time keeping a given constant area speed while solution polygonal curves keep belonging to the polygonal class.

math.NA↗