Enhancement of disturbance wave amplification due to the intrinsic three-dimensionalisation of laminar separation bubbles
| Autor: | Daniel Rodriguez, Elmer M. Gennaro |
|---|---|
| Přispěvatelé: | Universidade Federal Fluminense (UFF), Universidade Estadual Paulista (Unesp) |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Physics
020301 aerospace & aeronautics Waviness Bubble Aerospace Engineering Laminar flow 02 engineering and technology Mechanics Vorticity 01 natural sciences Instability 010305 fluids & plasmas Physics::Fluid Dynamics Laminar separation bubbles Aerodynamics Amplitude 0203 mechanical engineering Convective instability Flow Instability 0103 physical sciences Laminar-turbulent transition Laminar-Turbulent transition Parabolised stability equations |
| Zdroj: | Scopus Repositório Institucional da UNESP Universidade Estadual Paulista (UNESP) instacron:UNESP |
| Popis: | Made available in DSpace on 2020-12-12T00:57:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-10-01 Previous studies demonstrated that laminar separation bubbles (LSBs) 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 dominates the physics. The co-existence of the two instability mechanisms is investigated herein by means of three-dimensional parabolised 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 in a remarkable enhancement of the amplitude growth and a three-dimensional arrangement of the disturbance waves in the aft portion of the bubble. Present findings suggest that the oblique transition scenario should be expected in LSBs dominated by the convective instability, unless high-amplitude disturbances are imposed. Laboratory of Theoretical and Applied Mechanics (LMTA) Graduate Program in Mechanical Engineering (PGMEC) Department of Mechanical Engineering Universidade Federal Fluminense NiteróiRJ São Paulo State University (UNESP) Campus São João da Boa VistaSãn João da Boa VistaSP São Paulo State University (UNESP) Campus São João da Boa VistaSãn João da Boa VistaSP |
| Databáze: | OpenAIRE |
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