A SUBMODEL OF THE ROTATIONAL MOTIONS OF A GAS IN A UNIFORM FORCE-FIELD

An invariant submodel, constructed using a subalgebra of the sum of th e rotation, time transfer and Galilean transfer is considered within t he framework of the Podmodeli program [1]. A group classification is c onstructed and simple solutions are obtained. The submodel is reduced to symmetrical form. Assertions are made on the hyperbolicity, charact eristics and force discontinuities. The necessary conditions for solut ions to exist without discontinuities on the axis of symmetry are deri ved and their asymptotic submodel is investigated. (C) 1998 Elsevier S cience Ltd. All rights reserved.