Drag coefficient of unsubmerged rigid vegetation stems in open channel flows

Umesh C. Kothyari, Kenjirou Hayashi, Haruyuki Hashimoto

Research output: Contribution to journalArticle

72 Citations (Scopus)

Abstract

Results of an experimental study on the drag force measurement involving a single stem kept in a channel flow stem array are presented. The data collected herein and those from literature indicate that the stem drag coefficient logarithmically increases with the areal stem density. The stem Reynolds number is noticed to have only a small effect on the stem drag coefficient which was however found to depend on the stem staggering pattern. The drag coefficient is less influenced by the Froude number in subcritical flows but it decreases with the Fraude number in supercritical flows. New relationships are proposed for the stem drag coefficient which appear useful in partitioning the total flow resistance of vegetated bed streams into the stem and the bed particle resistances. The bed particle resistance applies to sediment transport through such vegetated flows for which the average flow velocity is available.

Original languageEnglish
Pages (from-to)691-699
Number of pages9
JournalJournal of Hydraulic Research
Volume47
Issue number6
DOIs
Publication statusPublished - Dec 1 2009

Fingerprint

Open channel flow
open channel flow
drag coefficient
Drag coefficient
stem
vegetation
Froude number
Force measurement
Sediment transport
Channel flow
Flow velocity
Drag
Reynolds number
supercritical flow
stream bed
channel flow
flow velocity
drag
sediment transport
partitioning

All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Water Science and Technology

Cite this

Drag coefficient of unsubmerged rigid vegetation stems in open channel flows. / Kothyari, Umesh C.; Hayashi, Kenjirou; Hashimoto, Haruyuki.

In: Journal of Hydraulic Research, Vol. 47, No. 6, 01.12.2009, p. 691-699.

Research output: Contribution to journalArticle

Kothyari, Umesh C. ; Hayashi, Kenjirou ; Hashimoto, Haruyuki. / Drag coefficient of unsubmerged rigid vegetation stems in open channel flows. In: Journal of Hydraulic Research. 2009 ; Vol. 47, No. 6. pp. 691-699.
@article{387e44070e704dba8627fcc29007af37,
title = "Drag coefficient of unsubmerged rigid vegetation stems in open channel flows",
abstract = "Results of an experimental study on the drag force measurement involving a single stem kept in a channel flow stem array are presented. The data collected herein and those from literature indicate that the stem drag coefficient logarithmically increases with the areal stem density. The stem Reynolds number is noticed to have only a small effect on the stem drag coefficient which was however found to depend on the stem staggering pattern. The drag coefficient is less influenced by the Froude number in subcritical flows but it decreases with the Fraude number in supercritical flows. New relationships are proposed for the stem drag coefficient which appear useful in partitioning the total flow resistance of vegetated bed streams into the stem and the bed particle resistances. The bed particle resistance applies to sediment transport through such vegetated flows for which the average flow velocity is available.",
author = "Kothyari, {Umesh C.} and Kenjirou Hayashi and Haruyuki Hashimoto",
year = "2009",
month = "12",
day = "1",
doi = "10.3826/jhr.2009.3283",
language = "English",
volume = "47",
pages = "691--699",
journal = "Journal of Hydraulic Research/De Recherches Hydrauliques",
issn = "0022-1686",
publisher = "International Association of Hydraulic Engineering Research",
number = "6",

}

TY - JOUR

T1 - Drag coefficient of unsubmerged rigid vegetation stems in open channel flows

AU - Kothyari, Umesh C.

AU - Hayashi, Kenjirou

AU - Hashimoto, Haruyuki

PY - 2009/12/1

Y1 - 2009/12/1

N2 - Results of an experimental study on the drag force measurement involving a single stem kept in a channel flow stem array are presented. The data collected herein and those from literature indicate that the stem drag coefficient logarithmically increases with the areal stem density. The stem Reynolds number is noticed to have only a small effect on the stem drag coefficient which was however found to depend on the stem staggering pattern. The drag coefficient is less influenced by the Froude number in subcritical flows but it decreases with the Fraude number in supercritical flows. New relationships are proposed for the stem drag coefficient which appear useful in partitioning the total flow resistance of vegetated bed streams into the stem and the bed particle resistances. The bed particle resistance applies to sediment transport through such vegetated flows for which the average flow velocity is available.

AB - Results of an experimental study on the drag force measurement involving a single stem kept in a channel flow stem array are presented. The data collected herein and those from literature indicate that the stem drag coefficient logarithmically increases with the areal stem density. The stem Reynolds number is noticed to have only a small effect on the stem drag coefficient which was however found to depend on the stem staggering pattern. The drag coefficient is less influenced by the Froude number in subcritical flows but it decreases with the Fraude number in supercritical flows. New relationships are proposed for the stem drag coefficient which appear useful in partitioning the total flow resistance of vegetated bed streams into the stem and the bed particle resistances. The bed particle resistance applies to sediment transport through such vegetated flows for which the average flow velocity is available.

UR - http://www.scopus.com/inward/record.url?scp=76149087483&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=76149087483&partnerID=8YFLogxK

U2 - 10.3826/jhr.2009.3283

DO - 10.3826/jhr.2009.3283

M3 - Article

AN - SCOPUS:76149087483

VL - 47

SP - 691

EP - 699

JO - Journal of Hydraulic Research/De Recherches Hydrauliques

JF - Journal of Hydraulic Research/De Recherches Hydrauliques

SN - 0022-1686

IS - 6

ER -