Review of viscous internal flows models

Review of wide spread simplified models for numerical investigation of viscous flow through nozzles and tunnels is presented. The most attention of the review is turned to details of stationary flow calculations in wide ranges of Mach number at moderate and large Rynolds numbers, in particular viscous flow through Laval nozzle. The commonly used parabolized models and common numerical methods for their calculations are presented, and new models of smooth channel approximation with effective numerical non-iterating and marching methods for them as well. The hierarchy of simplified models for internal flows is established and comparative analysis of internal and similar external models for viscous flows is presented. The analogy in numerical methods of the approaches is found.