Scattering of sound by an aerofoil of finite span in a compressible stream

Modeling fan broadband noise from jet engines and rod-airfoil benchmark case for broadband noise prediction

“…Flow compressibility can appreciably change airfoil gust response. Graham [39] and Adamczyk and Brand [40] derived closed-form solutions for the compressible skewed-gust problem.…”

“…14 shows the variation of unsteady lift coefficient with respect to reduced frequency.In this figure, the unsteady lift is computed using the LINSUB code (shown as rectilinear cascade response), as well as using the incompressible[6] and compressible[40] Sears functions.The cascade response shows a sharp discontinuity indicating cascade resonance (mode cut-off) around σ = 1.8. Single-airfoil response functions don't exhibit this.…”