Alternative interpretation of the Superpipe data and motivation for CICLoPE: The effect of a decreasing viscous length scale
2016 (English)In: European journal of mechanics. B, Fluids, ISSN 0997-7546, E-ISSN 1873-7390, Vol. 58, 109-116 p.Article in journal (Refereed) PublishedText
Pressurization and cryogenic conditions have been used in some experiments to change the kinematic viscosity v of the flowing gas by many orders of magnitude in order to achieve high Reynolds number conditions in facilities of limited size. This leads to a substantial reduction of the viscous length scale l* = v/u(tau), as in the so-called Princeton "Superpipe" experiments, We demonstrate that the limited dimensions of the facilities and probes can lead to inaccuracies in the near-wall measurements for increasing Reynolds number. Specifically, a lack of accurate wall-normal probe positioning is simulated using three different datasets of wall-bounded turbulent flows. Relatively large errors in the overlap region parameters are observed for position errors of small physical magnitude that become greatly amplified in wall units as l* is reduced. This offers an alternative interpretation to some of the key findings reported by the Superpipe team, such as the increasing lower limit of the logarithmic region y(log,min)(+), the existence of a power law region between the wall and the logarithmic layer, and the "mixing transition" phenomenon in wall bounded turbulence.
Place, publisher, year, edition, pages
Elsevier, 2016. Vol. 58, 109-116 p.
Experimental limitations, Wall-bounded turbulence, Pitot tubes, Superpipe, CICLoPE
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-189915DOI: 10.1016/j.euromechflu.2016.03.010ISI: 000378961900012ScopusID: 2-s2.0-84964720778OAI: oai:DiVA.org:kth-189915DiVA: diva2:950364
QC 201607292016-07-292016-07-252016-07-29Bibliographically approved