Aerodynamic forces due to blade-tip clearance eccentricity are a known destabilizing source in rotating machinery with unshrouded impellers. Dynamic also appear shrouded impellers, changes the pressure gap between impeller casing and its shroud. These load-dependent typically characterized by cross-coupled stiffness coefficient (k > 0). This paper reviews archival literature for quantificati...

Although wet (oil injected) and dry (oil free) screw compressors are widely used in many applications, limited information is available regarding the pulsation, vibration, and noise problems associated with these types of compressors. This tutorial discusses such problems and includes case histories where field testing was performed, and provides design recommendations. Both wet and dry screw c...

Considerable progress in development and application of computational fluid dynamics (CFD) for aeroengine internal flow systems has been made in recent years. CFD is regularly used in industry for assessment of air systems, and the performance of CFD for basic axisymmetric rotor/rotor and stator/rotor disc cavities with radial throughflow is largely understood and documented. Incorporation of t...

A general finite-difference procedure is presented for the calculation of steady, two-dimensional 'parti-ally-parabolic' flows, with special reference to turbine cascade problems. It can be used for incompressible, subsonic, supersonic or transonic flows. It can be characterised as an 'iterative space-marching' method. The method is more economical in computer storage than time-marching procedu...