Vortical patterns in turbulent flow downstream a 90° curved pipe at high Womersley numbers
2013 (English)In: International Journal of Heat and Fluid Flow, ISSN 0142-727X, E-ISSN 1879-2278, Vol. 44, 692-699 p.Article in journal (Refereed) Published
The present experimental work focuses on highly pulsatile, i.e. inertia dominated, turbulent flow downstream a curved pipe and aims at investigating the vortical characteristics of such a flow. The flow parameters (Dean and Womersley number) investigated are of the same order as those met in the internal combustion engine environment. The technique employed is time-resolved stereoscopic particle image velocimetry at different cross-sections downstream the pipe bend. These measurements allow the large-scale structures that are formed to be analyzed by means of proper orthogonal decomposition. The flow field changes drastically during a pulsatile cycle, varying from a uniform flow direction across the pipe section from the inside to the outside of the bend to vortical patterns consisting of two counter-rotating cells. This study characterizes and describes pulsatile curved pipe flow at Womersley numbers much higher than previously reported in the literature. Furthermore, the oscillatory behaviour of the Dean cells for the steady flow - the so-called 'swirl switching' - is investigated for different downstream stations from the bend exit and it is shown that this motion does not appear in the immediate vicinity of the bend, but only further downstream.
Place, publisher, year, edition, pages
2013. Vol. 44, 692-699 p.
Curved pipe, Proper orthogonal decomposition, Pulsatile flow, Stereoscopic particle image velocimetry, Turbulent flow, Counter-rotating cells, Curved pipes, Flow downstream, Flow parameters, Large-scale structure, Proper orthogonal decompositions, Womersley numbers, Flow visualization, Internal combustion engines, Principal component analysis, Velocimeters, Velocity measurement
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-139863DOI: 10.1016/j.ijheatfluidflow.2013.09.008ISI: 000329594600061ScopusID: 2-s2.0-84888431227OAI: oai:DiVA.org:kth-139863DiVA: diva2:690097
FunderSwedish Energy Agency
QC 201401222014-01-222014-01-152014-05-23Bibliographically approved