Details:

Creators:
Morales, Reinaldo ; Ettema, Robert
Morales, Reinaldo ; Ettema, Robert Less -
Corporate Creators:
University of Wyoming. Department of Civil and Architectural Engineering
Corporate Contributors:
North Dakota State University
Subject/TRT Terms:
[+]
Bridge Abutments Channel Flow Channels (Waterways) Critical Depth Depth-averaged Modeling, Flow Models, Compound Channels Digital Simulation Simulation Two Dimensional Flow
Resource Type:
Tech Report
Geographical Coverage:
Wyoming
Corporate Publisher:
North Dakota State University
Abstract:
Two-dimensional, depth-averaged flow models are used to study the distribution of flow around spill-through abutments situated on floodplains in compound channels and rectangular channels (flow on very wide floodplains may be treated as rectangular channels). The study leads to useful insights regarding distributions of flow velocity, unit discharge, and boundary shear stress at spill-through abutments. It also presents insights from extensive assessment of uncertainty associated with the use of depth-averaged modeling of flow at abutments. Of substantial use for design determination of abutment scour at bridge waterways is estimation of the magnitude of peak values of flow velocity, boundary shear stress, and unit discharge in the region where scour develops. The study, by showing how abutment flow fields adjust in response to variations of abutment length, floodplain width, and main channel dimensions, yields important trends regarding the magnitude of amplification factors for depth-averaged velocity, unit discharge, bed shear stress, and distance to peak unit discharge. Early studies are shown to provide rather limited and inadequate amplification values associated only with a narrow range of abutment and channel geometries examined. The present study comprises a much broader range of abutment lengths, channel shapes, and floodplain dimensions than heretofore reported in the literature. The study’s insights, from its assessment of uncertainty associated with the use of depth-averaged modeling of flow at abutments, yield a relationship for estimating the optimum mesh size for use with depth-averaged models. The relationship is applicable to other subsequent studies using depth-averaged models of flow around abutments or similar hydraulic structures. Prior studies addressing the effect of mesh size on numerical error have not provided a recommendation for an average optimum mesh size. The study also gives focused recommendations for topics requiring further investigation.
Format:
PDF
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:3ff89b23e5d11725dfcf3facb50ed23a0bfc5c2b31961b0a63964fee3edd0830
Download URL:
https://rosap.ntl.bts.gov/view/dot/23173/dot_23173_DS1.pdf
File Type:

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