Quasi-steady friction in transient polytropic flow (Q1390171)

An accurate method of integrating quasi-steady friction in transient polytropic flows is introduced and is justified both physically and analytically. When applied to subsonic flows, the method is found to be especially informative at higher Mach numbers where existing methods of integration can lead to serious errors in mass conservation. The method is used to assess the accuracy of widely used finite difference representations of quasi-steady friction, attention focusing principally on solutions obtained using the method of characteristics.