Journal of Fluid Mechanics

The plane Symmetric sudden-expansion flow at low Reynolds numbers

F.  Durst a1, J. C. F.  Pereira a1p1 and C.  Tropea a1
a1 Lehrstuhl für Strömungsmechanik, Universität Erlangen-Nürnberg, Cauerstr. 4, D-8520 Erlangen, Germany

Article author query
durst f   [Google Scholar] 
pereira jc   [Google Scholar] 
tropea c   [Google Scholar] 


Detailed velocity measurements and numerical predictions are presented for the flow through a plane nominally two-dimensional duct with a Symmetric sudden expansion of area ratio 1:2. Both the experiments and the predictions confirm a symmetry-breaking bifurcation of the flow leading to one long and one short Separation zone for channel Reynolds numbers above 125, based on the upstream channel height and the maximum flow velocity upstream. With increasing Reynolds numbers above this value, the short separated region remains approximately constant in length whereas the long region increases in length.

The experimental data were obtained using a one-component laser-Doppler anemometer at many Reynolds number values, with more extensive measurements being performed for the three Reynolds numbers 70, 300 and 610. Predictions were made using a finite volume method and an explicit quadratic Leith type of temporal discretization. In general, good agreement was found between measured and predicted velocity profiles for all Reynolds numbers investigated.

(Published Online April 26 2006)
(Received April 20 1989)
(Revised August 5 1992)

p1 Present address: Instituto Superior Técnico, Department of Mechanical Engineering, Av. Rovisco Pais, Lisbon, Portugal.