The effect of wall roughness, which is strong in turbulent flows often, is neglected in laminar flows, though without justification. With an experimental set-up which allows for changes in the relative roughness of a channel without requiring manipulation of the rough channel surface, it can be shown that there is a non-negligible influence of wall roughness even for laminar flows. Based on the consideration of entropy production in these flows, an increased dissipation rate in the vicinity of the roughness elements is identified as the physical mechanism that leads to an increased total head loss when the walls are no longer smooth.
Description
SpringerLink - Experiments in Fluids, Volume 49, Number 2
%0 Journal Article
%1 springerlink:10.1007/s00348-009-0811-6
%A Gloss, D.
%A Herwig, H.
%C Berlin / Heidelberg
%D 2010
%I Springer
%J Experiments in Fluids
%K 2010 experiment flow irreversibility laminar
%P 461-470
%R 10.1007/s00348-009-0811-6
%T Wall roughness effects in laminar flows: an often ignored though significant issue
%U http://dx.doi.org/10.1007/s00348-009-0811-6
%V 49
%X The effect of wall roughness, which is strong in turbulent flows often, is neglected in laminar flows, though without justification. With an experimental set-up which allows for changes in the relative roughness of a channel without requiring manipulation of the rough channel surface, it can be shown that there is a non-negligible influence of wall roughness even for laminar flows. Based on the consideration of entropy production in these flows, an increased dissipation rate in the vicinity of the roughness elements is identified as the physical mechanism that leads to an increased total head loss when the walls are no longer smooth.
@article{springerlink:10.1007/s00348-009-0811-6,
abstract = {The effect of wall roughness, which is strong in turbulent flows often, is neglected in laminar flows, though without justification. With an experimental set-up which allows for changes in the relative roughness of a channel without requiring manipulation of the rough channel surface, it can be shown that there is a non-negligible influence of wall roughness even for laminar flows. Based on the consideration of entropy production in these flows, an increased dissipation rate in the vicinity of the roughness elements is identified as the physical mechanism that leads to an increased total head loss when the walls are no longer smooth.},
added-at = {2011-04-12T14:36:58.000+0200},
address = {Berlin / Heidelberg},
affiliation = {Hamburg University of Technology Hamburg Germany},
author = {Gloss, D. and Herwig, H.},
biburl = {https://www.bibsonomy.org/bibtex/2213f6ccd350cf74d695465b802f55419/thorade},
description = {SpringerLink - Experiments in Fluids, Volume 49, Number 2},
doi = {10.1007/s00348-009-0811-6},
interhash = {4cf02ec7f04290ef8d27aa2349e46632},
intrahash = {213f6ccd350cf74d695465b802f55419},
issn = {0723-4864},
issue = {2},
journal = {Experiments in Fluids},
keyword = {Physics and Astronomy},
keywords = {2010 experiment flow irreversibility laminar},
pages = {461-470},
publisher = {Springer},
timestamp = {2011-04-12T14:36:58.000+0200},
title = {Wall roughness effects in laminar flows: an often ignored though significant issue},
url = {http://dx.doi.org/10.1007/s00348-009-0811-6},
volume = 49,
year = 2010
}