The instability of the boundary layer over a disk rotating in an enforced axial flow
journal contributionposted on 24.01.2012, 15:26 by Z. Hussain, Stephen J. Garrett, S.O. Stephen
We consider the convective instability of stationary and traveling modes within the boundary layer over a disk rotating in a uniform axial ﬂow. Complementary numerical and high Reynolds number asymptotic analyses are presented. Stationary and traveling modes of type I (crossﬂow) and type II (streamline curvature) are found to exist within the boundary layer at all axial ﬂow rates considered. For low to moderate axial ﬂows, slowly traveling type I modes are found to be the most ampliﬁed, and quickly traveling type II modes are found to have the lower critical Reynolds numbers. However, near-stationary type I modes are expected to be selected due to a balance being struck between onset and ampliﬁcation. Axial ﬂow is seen to stabilize the boundary layer by increasing the critical Reynolds numbers and reducing ampliﬁcation rates of both modes. However, the relative importance of type II modes increases with axial ﬂow and they are, therefore, expected to dominate for sufﬁciently high rates. The application to chemical vapour deposition (CVD) reactors is considered.