The discrete temporal eigenvalue spectrum of the generalised Hiemenz flow as solution of the Orr-Sommerfeld equation (Q1329830)

This paper discusses the linear stability of generalized Hiemenz flow which is obtained by adding a spanwise velocity component to the classical Hiemenz stagnation point flow. This flow is strictly parallel in spanwise direction and serves as a model for attachment-line stability. Neglecting the chordwise and wall normal base velocities in a non-rational approximation, the full linear stability problem is reduced to the solution of the Orr-Sommerfeld equation. As is well known, the critical Reynolds number is overestimated by this approximation, but the frequency spectrum of the most unstable eigenvalues turns out to be fairly accurate for large Reynolds numbers and may serve as a cheap alternative for engineering purposes.