Ob approksimatsii poverkhnostnykh proizvodnykh funktsiy s primeneniem integral'nykh operatorov

Abstract

Integral formulas are presented for approximating the surface gradient (of a scalar function given on a surface) and divergence (of a tangent vector field given on a surface) that are analogs of the well-known formulas for the derivatives of a function on a plane. Estimates of the error in the approximation of these functions are obtained. The question of subsequent approximation of the integrals that give expression for the surface gradient and divergence by quadrature sums over the values of the function under study at the nodes selected on the cells of the unstructured grid approximating the surface is also considered.