Nonlinear dynamics and hydrodynamic feedback in two-dimensional double cavity flow

F TUERKE; L PASTUR; Y FRAIGNEAU; D SCIAMARELLA; GUILLERMO ARTANA

JOURNAL OF FLUID MECHANICS

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2017 vol. 813 p. 1 - 22

0022-1120

This paper reports results obtained with two-dimensional numerical simulations ofviscous incompressible flow in a symmetric channel with a sudden expansion andcontraction, creating two facing cavities; a so-called double cavity. Based on timeseries recorded at discrete probe points inside the double cavity, different flow regimesare identified when the Reynolds number and the intercavity distance are varied. Thetransition from steady to chaotic flow behaviour can in general be summarized asfollows: steady (fixed) point, period-1 limit cycle, intermediate regime (includingquasi-periodicity) and torus breakdown leading to toroidal chaos. The analysis ofthe intracavity vorticity reveals a ?carousel? pattern, creating a feedback mechanism,that influences the shear-layer oscillations and makes it possible to identify in whichregime the flow resides. A relation was found between the ratio of the shear-layerfrequency peaks and the number of small intracavity structures observed in the flowfield of a given regime. The properties of each regime are determined by the interplayof three characteristic time scales: the turnover time of the large intracavity vortex,the lifetime of the small intracavity vortex structures and the period of the dominantshear-layer oscillations.