Session
Session 6 2022
Start Date
10-27-2022 12:00 AM
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Sharifi M., Majdzadeh Tabatabai, M.R., and Ghoreishi Najafabadi, S.H. (2022). "2-D Simulation of Flow Structures Over Dunes for Flow Characteristics Estimation" in "9th IAHR International Symposium on Hydraulic Structures (9th ISHS)". Proceedings of the 9th IAHR International Symposium on Hydraulic Structures – 9th ISHS, 24-27 October 2022, IIT Roorkee, Roorkee, India. Palermo, Ahmad, Crookston, and Erpicum Editors. Utah State University, Logan, Utah, USA, 11 pages (DOI: 10.26077/f04b-f7cd) (ISBN 978-1-958416-07-5).
Abstract
Rivers have undulated beds, which are called bedforms. Depending on the hydraulic conditions, the bedforms have different types that cause resistance in the flow. Despite various research and experiments on bedforms, the topic is still debatable and requires further research. The present study is mainly focused on simulating the flow motion numerically on dunes in open channels to evaluate the effect of dune geometry on flow structure. Twenty-nine simulations were conducted to study the effect of the geometry of five types of dunes with different angles and heights under different hydraulic conditions and bed roughnesses. RANS and DES turbulence models were used to simulate small and large-scale dunes, respectively. The results of the numerical model were compared with the experimental results of previous researchers to validate the work, indicating the appropriate accuracy of the numerical model. Then, an empirical equation was adopted to evaluate the effect of dune geometry on flow hydraulics by considering the equations of previous researchers. Finally, sensitivity analyses were carried out to determine the dependence of each parameter in this equation.
2-D Simulation of Flow Structures Over Dunes for Flow Characteristics Estimation
Rivers have undulated beds, which are called bedforms. Depending on the hydraulic conditions, the bedforms have different types that cause resistance in the flow. Despite various research and experiments on bedforms, the topic is still debatable and requires further research. The present study is mainly focused on simulating the flow motion numerically on dunes in open channels to evaluate the effect of dune geometry on flow structure. Twenty-nine simulations were conducted to study the effect of the geometry of five types of dunes with different angles and heights under different hydraulic conditions and bed roughnesses. RANS and DES turbulence models were used to simulate small and large-scale dunes, respectively. The results of the numerical model were compared with the experimental results of previous researchers to validate the work, indicating the appropriate accuracy of the numerical model. Then, an empirical equation was adopted to evaluate the effect of dune geometry on flow hydraulics by considering the equations of previous researchers. Finally, sensitivity analyses were carried out to determine the dependence of each parameter in this equation.