POD analysis of stereoscopic PIV data from swirling turbulent flow through a pipe bend
2012 (English)Report (Other academic)
Coherent structures in turbulent swirling flow through a pipe bend are investigated experimentally by means of stereoscopic particle image velocimetry. Inparticular, the effect of the imposed swirling motion on the Dean vortices aswell as the very-large-scale structures is examined for a wide range of swirlnumbers. Proper orthogonal decomposition is employed to rank the spatialmodes by energy content and extract the underlying secondary swirling motionas well as the large-scale structures present in the flow field. Moreover theoriginal snapshots are reconstructed by using only a few of the most energeticmodes and ease visualization of the structures by inhomogeneously filtering theflow fields. Phenomena such as the unsteady motion of the Dean vortices, theso called swirl switching, in the non-swirling turbulent flow case and the tiltingof the very-large-scale structures in a highly swirling turbulent flow are capturedand presented. The results presented here are preliminary and furtheranalysis is planned in the future. Nevertheless, this work is believed to provideunique data as the first experimental study on swirling flows through a pipebend which is not restricted to single-point measurements.
Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2012.
IdentifiersURN: urn:nbn:se:kth:diva-93728OAI: oai:DiVA.org:kth-93728DiVA: diva2:523476
QC 201204252012-04-252012-04-242012-05-14Bibliographically approved