Approximation of evolutionary processes with distributed parameters on a network

The paper considers the approximation of mathematical models of network-like evolutionary transport processes as applied to differential systems with distributed parameters on a network (graph). An approach is indicated that uses the application of the theory of classical computational methods, which consists in reducing the investigated problem to systems of algebraic equations (auxiliary finitedimensional problems) in which the values of the grid functions at the points of partition of the edges of the graph are unknown. At the same time, there is a fairly wide opportunity for choosing different types of convergent difference schemes that are significantly different from each other: explicit difference schemes, implicit difference schemes, analogs of Krank-Nicholson difference schemes (below, in order not to load the study with technical difficulties, explicit difference schemes are used). It should be noted a characteristic feature of the studied mathematical models inherited by the rheological structure of the graph — the presence of singular points of the graph at which the differential equation is not determined (nodes or vertices of the graph) and is replaced by generalized Kirchhoff conditions. The formalisms of the latter describe the laws of continuum transfer at these points and require a separate approach to approximation issues (in the work, for the sake of simplicity, classical difference relations are used). It should also be noted that the use of an implicit difference scheme or the Crank-Nicholson scheme for approximation requires additional analysis of auxiliary finite-dimensional problems (solvability, uniform boundedness of approximations to the solution of the original problem), but it significantly increases the accuracy of calculating approximations. The use of an explicit difference scheme is freed from studying some of these issues, however (and this, when analyzing some applied problems, can be a significant obstacle to use) gives a rather large error in determining the solution to the original problem. The given particular examples of applied character illustrate the ways of numerical analysis of differential systems with carriers on an arbitrary network (graph). The results obtained are quite simply transferred to the study of wave processes and oscillation phenomena in transport processes by numerical methods.

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