Unsteady lifting surface theory for supersonic through-flow fan

The purpose of this work is to predict analytically the unsteady loading on vibrating blades of a supersonic through-flow fan and conduct the parametric study of the aerodynamic instability. A linearized unsteady lifting surface theory on the basis of the finite radial eigenfunction series approximation is developed. It is assumed that each blade vibrates with a small displacement amplitude under zero mean loading. Numerical results for pure bending, pure torsional and combined bending and torsional vibrations are presented to demonstrate influences of interblade phase angle, location of torsion axis, axial Mach number and reduced frequency on the aerodynamic instability of blade motions.