TITLE:
Concept of Bed Roughness Boundary Layer and Its Application to Bed Load Transport in Flow with Non-Submerged Vegetation
AUTHORS:
Ho-Seong Jeon, Makiko Obana, Tetsuro Tsujimoto
KEYWORDS:
Flow with Non-Submerged Vegetation, Boundary Layer, Bed Roughness, Bed Load Transport
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.6 No.10,
July
28,
2014
ABSTRACT: Ecosystem
conservation has become one of the purposes in river management as well as
flood mitigation and water resources management, and understanding of river
flow and morphology in a stream with vegetation becomes important. Recently 2D
depth averaged analysis is familiar even in a stream with vegetation by taking
account of form drag due to vegetation. However, the shear stress in vegetated
area is not properly described because the resistance law due to bed roughness
is not reasonably modified in vegetated area. In this study, we discussed the
bed roughness boundary layer in flow with non-submerged vegetation to deduce a
reasonable relation between U and u* in vegetated area toward improving
the analysis of sediment transport. The results show that the modification of
resistance law using by thickness, velocity distribution in that layer was
found to bring significant improvement of accurate estimation of shear velocity
and subsequently the sediment transport. The proposed modification is improved by
2D depth averaged analysis based on this concept, and its application is
certificated through flume experiment.