A comparative study of two unsteady one-dimensional open channel flow models: Full Equations Model (FEQ) and River Analysis System (HEC-RAS)

Ancalle Reyes, David S

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https://hdl.handle.net/2142/92682 Copy

Description

Title

A comparative study of two unsteady one-dimensional open channel flow models: Full Equations Model (FEQ) and River Analysis System (HEC-RAS)

Author(s)

Ancalle Reyes, David S

Issue Date

2016-07-22

Director of Research (if dissertation) or Advisor (if thesis)

Garcia, Marcelo H.

Department of Study

Civil & Environmental Eng

Discipline

Civil Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Open channel
• Flow
• Hydraulic
• Hydrologic engineering center's river analysis system (HEC-RAS)
• Full equations model (FEQ)
• Unsteady
• One-dimensional
• Dam break
• Bankfull flow
• Tidal effect

Abstract

In this work, a comparative study was performed to determine the similarities and differences between two unsteady, one-dimensional, open channel hydraulic models. The models in question are the Full Equations Model (FEQ 10.61), distributed by the U.S. Geological Survey, and the Hydrologic Engineering Center's River Analysis System (HEC-RAS 4.1), developed by the U.S. Army Corps of Engineers. The two models weretested to simulate three cases: 1) a sharp-crested hydrograph resulting from a dam break, 2) bankfull flow resulting from overflow in a channel with wide overbanks, and 3) backwater resulting from tidal effects in the Sacramento River. The dam break and overbank cases were validated with measurements from laboratory flumes. The Sacramento River case was validated with field measurements. The outputs of the models are hydrographs that plot stage or flow against time. These hydrographs were compared to measured hydrographs that plot the corresponding parameters. The parameters examined in this comparative study were as follows: peak flow, time to peak flow, shape of hydrographs, and accuracy of results. Additional model aspects such as computation times, ease of use, and the ability to model said case studies are noted. Conclusions are drawn based on the comparative analysis, presenting the strengths and weaknesses of the two models. From this analysis, it was determined that even though both models have the capability to simulate similar cases, FEQ can produce computations at a much faster rate than HEC-RAS. However, FEQ fails to model cases with overbank flow accurately. Future work is recommended based on the conclusions of the analysis, which includes expanding this study to include hydraulic structures.

Graduation Semester

2016-08

Type of Resource

text

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Copyright 2016 David Ancalle Reyes

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