Evolution of turbulence characteristics from straight to curved pipes
2013 (English)In: International Journal of Heat and Fluid Flow, ISSN 0142-727X, E-ISSN 1879-2278, Vol. 41, no SI, 16-26 p.Article in journal (Refereed) Published
Fully developed, statistically steady turbulent flow in straight and curved pipes at moderate Reynolds numbers is studied in detail using direct numerical simulations (DNS) based on a spectral element discretisation. After the validation of data and setup against existing DNS results, a comparative study of turbulent characteristics at different bulk Reynolds numbers Re-b = 5300 and 11,700, and various curvature parameters kappa = 0, 0.01, 0.1 is presented. In particular, complete Reynolds-stress budgets are reported for the first time. Instantaneous visualisations reveal partial relaminarisation along the inner surface of the curved pipe at the highest curvature, whereas developed turbulence is always maintained at the outer side. The mean flow shows asymmetry in the axial velocity profile and distinct Dean vortices as secondary motions. For strong curvature a distinct bulge appears close to the pipe centre, which has previously been observed in laminar and transitional curved pipes at lower Re-b only. On the other hand, mild curvature allows the interesting observation of a friction factor which is lower than in a straight pipe for the same flow rate. All statistical data, including mean profile, fluctuations and the Reynolds-stress budgets, is available for development and validation of turbulence models in curved geometries.
Place, publisher, year, edition, pages
Elsevier, 2013. Vol. 41, no SI, 16-26 p.
Wall turbulence, Pipe flow, Curvature effects, Reynolds-stress budgets, Coiled tube
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-124983DOI: 10.1016/j.ijheatfluidflow.2013.03.005ISI: 000321078700003ScopusID: 2-s2.0-84878568406OAI: oai:DiVA.org:kth-124983DiVA: diva2:638993
9th International Symposium on Engineering Turbulence Modelling and Measurements (ETMM), JUN 06-08, 2012, Thessaloniki, Greece
FunderSwedish e‐Science Research Center
QC 201308052013-08-052013-08-022015-11-18Bibliographically approved