The Effect of Axisymmetric Geometry on Boundary-Layer Transition as Predicted by Linear Stability Theory,
Abstract
Computations of the linear stability of laminar boundary layers have been used to obtain predictions of the ratio of the transition Reynolds number on a cone to that on a flat plate. The results show that this ratio is not given by a simple constant, but depends upon various parameters. In particular, the predictions indicate that transition will not occur at the same value of Reynolds number(deflected flow) on both the cone and the plate. Similarly, the results show that the ratio of transition Reynolds numbers is not equal to the ratio of the critical Reynolds numbers for the two bodies. If either of these suppositions were true, the transition Reynolds number ratio would be three; stability results indicate that this ratio can be less than unity. Among other things, the ratio depends upon the disturbance level in the free-stream. High free-stream disturbances push the ratio near three, while sufficiently small disturbances allow transition to occur earlier on the cone than on the plate. This is a consequence of the fact that on a plate the transition location is more sensitive to free-stream disturbances than it is on a cone.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1974
- Accession Number
- ADA004787
Entities
People
- C. L. Merkle
- D. R. S. Ko
- T. Kubota