Eventos Anais de eventos
ENCIT 2018
Brazilian Congress of Thermal Sciences and Engineering
DOES THE INTRINSIC THREE-DIMENSIONALIZATION OF LAMINAR SEPARATION BUBBLES ENHANCE ITS AMPLIFIER CHARACTER?
Submission Author:
Daniel Rodriguez , Madrid
Co-Authors:
Daniel Rodriguez, Elmer Gennaro, Leandro Franco de Souza
Presenter: Daniel Rodriguez
doi://10.26678/ABCM.ENCIT2018.CIT18-0229
Abstract
Previous studies demonstrate laminar separation bubbles (LSB) in the absence of external disturbances or forcing are intrinsically unstable with respect to a three-dimensional instability of centrifugal nature. This instability produces topological modifications of the recirculation region with the introduction of streamwise vorticity in an otherwise purely two-dimensional time-averaged flows. Concurrently, the existence of spanwise inhomogeneities in LSBs have been reported in experiments in which the amplification of convective instability waves is seen to dominate the physics. The co-existence of the two instability mechanisms and its interactions are investigated here by means of three-dimensional Parabolized Stability Equations. The spanwise waviness of the LSB on account of the primary instability is found to modify the amplification of incoming disturbance waves in the linear regime, resulting into a staggered arrangement of the disturbances in the aft portion of the bubble, reminiscent of an oblique transition scenario.
Keywords
Laminar separation bubble, Parabolized Stability Equations, Tollmien-Schlichting waves, Flow instability
