Eventos Anais de eventos
ENCIT 2018
Brazilian Congress of Thermal Sciences and Engineering
COMPRESSIBILITY EFFECTS ON THE CENTRIFUGAL INSTABILITY OF LAMINAR SEPARATION BUBBLES
Submission Author:
Elmer Gennaro , SP , Brazil
Co-Authors:
Elmer Gennaro, Bruna Dias Pires de Souza, Daniel Rodriguez
Presenter: Elmer Gennaro
doi://10.26678/ABCM.ENCIT2018.CIT18-0066
Abstract
Separation bubbles have an intrinsic instability mechanism, which results in the appearance of spanwise- periodic three-dimensional structures. In incompressible flow, the instability mechanism responsible for three- dimensionality was found to become active under certain conditions and require of continuous external excitation to dominate the physics. We investigate if the compressibility could alter the qualitative picture. The model configuration for laminar separation bubble was a flat-plate boundary layer subjected to an adverse pressure gradient. The bubble considered is of the kind that occurs in the leading edge of a thin airfoil when it is at a high angle of attack. Direct numerical simulations were carried out to obtain two-dimensional base flows, and we achieved steady two-dimensional flows with peak reversed up to 16%. We find that the instability mechanism responsible for three-dimensionality has also become active in the compressible flow.
Keywords
Laminar separation bubble, modal stability analysis, Computational Fluid Dynamics
