Authors’ abstract: “4-quasiplanar mappings of almost quaternionic spaces with affine connection without torsion are investigated. Geometrically motivated definitions of these mappings are presented. Based an these definitions, fundamental forms of these mappings are found, which are equivalent to the forms of 4-quasiplanar mappings introduced a priori by I. Kurbatova [Sov. Math. 30, 100-104 (1986; Zbl 0602.53029)]”.
A G-structure on a Riemannian manifold is said to be integrable if it is preserved by the Levi-Civita connection. In the presented paper, the following non-integrable G-structures are studied: SO(3)-structures in dimension 5; almost complex structures in dimension 6; G-structures in dimension 7; Spin(7)-structures in dimension 8; Spin(9)-structures in dimension 16 and F-structures in dimension 26. G-structures admitting an affine connection with totally skew-symmetric torsion are characterized....
In this work, artificial compressibility method is used to solve steady and unsteady flows of viscous incompressible fluid. The method is based on implicit higher order upwind discretization of Navier-Stokes equations. The extension for unsteady simulation is considered by increasing artificial compressibility parameter or by using dual time stepping. The methods are tested on laminar flow around circular cylinder and used to simulate turbulent unsteady flows by URANS approach. The simulated cases...