The Use of a Distributed Body Force to Simulate Viscous Effects in 3D Flow Calculations

Three dimensional viscous flow calculations methods for turbomachinery are starting to become available but are not yet sufficiently well developed to be used for design purposes. Three dimensional inviscid calculations on the other hand are now well developed and are widely used for design purposes. This paper describes a method intermediate between fully viscous methods and inviscid methods. The viscous effects are approximated by a very simple model which can be tuned empirically to get the correct overall level of loss and which reproduces many of the details of real viscous flow, such as boundary layers and secondary flows. The method is a simple extension to a widely used inviscid method and enables viscous effects to be simulated with little extra computational cost compared to a 3D inviscid calculation.