The Effect of Compressibility on the Primary Global Instability of Unforced Laminar Separation Bubbles

Abstract: 

Laminar separation bubbles present a three-dimensional self-excited instability mechanism which leads to the appearance of spanwise-periodic structures. In incompressible flow, this mechanism was found to become active at conditions in which wave-like, two-dimensional perturbations are only convectively unstable. In the absence of continuous external excitation, the three-dimensional instability is expected to dominate the flow dynamics and initiate the laminar-turbulent transition. This work extends previous analyses by incorporating the effect of compressibility at subsonic conditions. Two-dimensional numerical simulations of a flat-plate boundary layer with a prescribed free-stream deceleration and acceleration are carried out to obtain a set of model laminar separation bubbles. A linear stability analysis is applied then, to study the influence of Reynolds and Mach numbers on the three-dimensional instability.

Author: 
Gennaro, EM
Souza, BDP
Rodriguez, D
Publication date: 
November 13, 2019
Publication type: 
Journal Article
Citation: 
Gennaro, E., Souza, B., & Rodríguez, D. (2019). The Effect of Compressibility on the Primary Global Instability of Unforced Laminar Separation Bubbles. Journal of the Brazilian Society of Mechanical Sciences and Engineering 41 …, Query date: 2024-12-09 21:28:55. https://scholar.google.com/citations?view_op=view_citation&hl=en&user=YmyOoaYAAAAJ&cstart=200&pagesize=100&citation_for_view=YmyOoaYAAAAJ:09LM3QYkMKUC