Numerical simulation of oscillating airfoil unsteady aerodynamics in supersonic flow

A continuing problem in the design of turbomachinery components for aircraft gas turbine engines is flow-induced vibrations. A key component in the prediction of flow induced vibrations is accurate calculation of the unsteady aerodynamic loading on the turbomachinery airfoils. In this investigation the steady pressure and first harmonic unsteady surface pressure coefficients determined from experiments are correlated with predictions from a two-dimensional nonlinear Euler/Thin-Layer Navier-Stokes analysis. Both inviscid and viscous flow solutions were generated. For the cases considered the airfoils were oscillated in the torsion mode about midchord. The experimental data used in this investigation is for the Seventh Standard Configuration. The flow conditions for the Seventh Standard Configuration are supersonic flow with a subsonic axial Mach number, which represents a supersonic unstalled flutter case. The airfoil section is representative of a fan or compressor blade tip section. The correlation between the steady experimental data and the inviscid/viscous predictions is rather poor. However, the comparison between the mathematical solutions for the unsteady surface pressure and the corresponding experimental data is generally better.