How do you analyze unsteady aerodynamic phenomena in turbomachinery?

Unsteady turbomachinery analysis addresses: Rotor-stator interaction (wake impingement, potential field effects), Blade flutter (aeromechanical instability), Forced response to upstream wakes, Rotating stall and surge inception, and Acoustic noise generation. Methods: Time-accurate RANS/URANS with full annulus or harmonic balance, LES for detailed turbulence, Linearized methods for flutter/forced response screening, and Time-transformation methods for blade count scaling. Validation through rig testing with unsteady pressure measurements, strain gauges, and tip timing. Analysis determines HCF life, flutter boundaries, and noise spectra. Computational cost is high (10^8+ cells, thousands of time steps) requiring HPC resources.