Direct Numerical Simulation of Transition in Compressible Flows
Abstract
This paper presents first results on the transition of the separated boundary layer along a compression ramp at Mach 5 as an example for today's capabilities of direct numerical simulation of transition in complex shear flows. The computational method is based on the 5th order hybrid compact-ENO method of Adams and Shariff, 1996. The flow parameters of the considered configuration are adjusted to an experimentally feasible configuration. The shock-induced laminar separation extends for about 20 incoming-boundary-layer thicknesses. We find that for the two-dimensional solution following a two-dimensional second mode instability imposed at inflow the unsteady fluctuations with respect to the mean remain small upto rather large excitation levels of the inflow disturbance. No indications for a global instability of the two-dimensional steady solution have been found so far. Even at large inflow-disturbance excitation levels the two-dimensional flow exhibits a split into a nearly steady solenoidal part and an unsteady acoustic part. If in addition to the second mode an unstable first oblique mode is imposed at inflow, streamwise vortices are generated in the detached shear layer.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2001
- Accession Number
- ADP013633
Entities
People
- N. A. Adams