Professor Karel Segeth is seventy
Program of the conference
Program of the conference
Program of the conference
Quilted Symmetry
Representing Seashells Surface
Results of Five Students from the Programmed Design Assignment, in the Formative Design Studio at Buffalo
Rheo-Art Application of Fluid Dynamics to Art Creation
Riemann solution for hyperbolic equations with discontinuous coefficients
This paper deals with a Riemann solution for scalar hyperbolic equations with discontinuous coefficients. In many numerical schemes of Godunov type in fluid dynamics, electromagnetic and so on, usually hyperbolic problems are solved to estimate fluxes. The exact solution is generally difficult to obtain, but good approximations are provided in many situations like Roe and HLLC Riemann solvers in fluid. However all these solvers assumes that the acoustic waves speeds are continuous which is not...
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Shoaling of nonlinear steady waves: maximum height and angle of breaking
A Fourier approximation method is used for modeling and simulation of fully nonlinear steady waves. The set of resulting nonlinear equations are solved by Newton's method. The shoaling of waves is simulated based on comparisons with experimental data. The wave heights and the angles of breaking are analysed until the limit of inadequacy of the numerical method. The results appear quite close to those criteria predicted by the theory of completely nonlinear surface waves and contribute to provide...
Smooth approximation and its application to some 1D problems
In the contribution, we are concerned with the exact interpolation of the data at nodes given and also with the smoothness of the interpolating curve and its derivatives. This task is called the problem of smooth approximation of data. The interpolating curve or surface is defined as the solution of a variational problem with constraints. We discuss the proper choice of basis systems for this way of approximation and present the results of several 1D numerical examples that show the quality of smooth...
Solutions of hypersingular integral equations over circular domains by a spectral method
The problem of a solving a class of hypersingular integral equations over the boundary of a nonplanar disc is considered. The solution is obtained by an expansion in basis functions that are orthogonal over the unit disc. A Fourier series in the azimuthal angle, with the Fourier coefficients expanded in terms of Gegenbauer polynomials is employed. These integral equations appear in the study of the interaction of water waves with submerged thin plates.
Some Common Themes in Visual Mathematical Art
Some practical aspects of parallel adaptive BDDC method
We describe a parallel implementation of the Balancing Domain Decomposition by Constraints (BDDC) method enhanced by an adaptive construction of coarse problem. The method is designed for numerically difficult problems, where standard choice of continuity of arithmetic averages across faces and edges of subdomains fails to maintain the low condition number of the preconditioned system. Problems of elasticity analysis of bodies consisting of different materials with rapidly changing stiffness may...
Some remarks on mixed approximation problem
Several years ago, we discussed the problem of approximation polynomials with Milan Práger. This paper is a natural continuation of the work we collaborated on. An important part of numerical analysis is the problem of finding an approximation of a given function. This problem can be solved in many ways. The aim of this paper is to show how interpolation can be combined with the Chebyshev approximation.
Současná aplikovaná matematika a počítačové modelování
Special issue: intersections of art and science
Spherically symmetric solutions to a model for interface motion by interface diffusion
The existence of spherically symmetric solutions is proved for a new phase-field model that describes the motion of an interface in an elastically deformable solid, here the motion is driven by configurational forces. The model is an elliptic-parabolic coupled system which consists of a linear elasticity system and a non-linear evolution equation of the order parameter. The non-linear equation is non-uniformly parabolic and is of fourth order. One typical application is sintering.
Steady and unsteady 2D numerical solution of generalized Newtonian fluids flow
This article presents the numerical solution of laminar incompressible viscous flow in a branching channel for generalized Newtonian fluids. The governing system of equations is based on the system of balance laws for mass and momentum. The generalized Newtonian fluids differ through choice of a viscosity function. A power-law model with different values of power-law index is used. Numerical solution of the described models is based on cell-centered finite volume method using explicit Runge–Kutta...