The effect of compressibility on the primary global instability of unforced laminar separation bubbles
| Autor: | Elmer M. Gennaro, Daniel Rodriguez, Bruna Dias Pires de Souza |
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| Rok vydání: | 2019 |
| Předmět: |
Physics
0209 industrial biotechnology Work (thermodynamics) Mechanical Engineering Applied Mathematics Flow (psychology) General Engineering Aerospace Engineering Laminar flow 02 engineering and technology Mechanics Instability Industrial and Manufacturing Engineering Physics::Fluid Dynamics Boundary layer symbols.namesake 020901 industrial engineering & automation Mach number Incompressible flow Automotive Engineering Compressibility symbols |
| Zdroj: | Journal of the Brazilian Society of Mechanical Sciences and Engineering. 41 |
| ISSN: | 1806-3691 1678-5878 |
| DOI: | 10.1007/s40430-019-2063-6 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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