Velocity field and parametric analysis of a subsonic, medium-Reynolds number cavity flow

Cavity flows are a class of flows bounded by material structures, where a recirculation region is present, and they are found in many practical applications. In the present study, the interaction between a boundary layer and an open parallelepipedic cavity develops a Kelvin–Helmholtz-like instabilit...

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Bibliographic Details
Published in:Experiments in fluids 2014-11, Vol.55 (11), p.1-18, Article 1822
Main Author: Faure, Thierry M.
Format: Article
Language:English
Subjects:
Acoustics
Aeroacoustics, atmospheric sound
Cavity flow
Emergence
Engineering
Engineering Fluid Dynamics
Engineering Thermodynamics
Exact sciences and technology
Fluid dynamics
Fluid flow
Fluid mechanics
Fluid- and Aerodynamics
Fundamental areas of phenomenology (including applications)
Heat and Mass Transfer
Holes
Instability
Instrumentation for fluid dynamics
Mechanics
Parametric analysis
Physics
Research Article
Stability
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Summary:Cavity flows are a class of flows bounded by material structures, where a recirculation region is present, and they are found in many practical applications. In the present study, the interaction between a boundary layer and an open parallelepipedic cavity develops a Kelvin–Helmholtz-like instability coupled with the cavity recirculation. PIV measurements of the flow are carried out in two orthogonal planes inside the cavity, for different aspect ratios, incompressible flow conditions, and Reynolds numbers in the range 1,900–12,000. Mean velocity and second-order moments of velocity fluctuations reveal the flow morphology. For particular conditions, centrifugal instabilities appear that are induced by flow curvature due to wall confinement. The use of an identification criterion indicates the presence of pairs of counter-rotating vortices winded around the recirculation. A parametric analysis is conducted, and the inviscid Rayleigh discriminant provides the potentially unstable flow regions inside the cavity. Finally, a stability parameter considering the ratio between centrifugal destabilizing effects and stabilizing viscous effects is carried out and gives thresholds for the emergence of the centrifugal instability. The study draws to an end with a comparison with a well-documented lid-driven cavity flow.
ISSN:0723-4864
1432-1114
DOI:10.1007/s00348-014-1822-5