Analytical Study of the Bed Roughness and Entrainment Ratio of Saline Density Currents on Hydraulic Jump

Density current is produced due to a density contrast with the ambient fluid. This density difference can result from dissolved solids, suspended materials, temperature, etc. Density jumps significantly influence the characteristics of the gravity currents and the ambient fluid (e.g., velocities and...

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Main Author: Nader Barahmand
Format: Article
Language:fas
Published: Marvdasht Branch, Islamic Azad University 2017-08-01
Series:مهندسی منابع آب
Subjects:
Online Access:https://wej.marvdasht.iau.ir/article_2436_ed098135734f8629cd13ae3a060cd830.pdf
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author Nader Barahmand
author_facet Nader Barahmand
author_sort Nader Barahmand
collection DOAJ
description Density current is produced due to a density contrast with the ambient fluid. This density difference can result from dissolved solids, suspended materials, temperature, etc. Density jumps significantly influence the characteristics of the gravity currents and the ambient fluid (e.g., velocities and concentrations). In this paper, the density jump is studied analytically by considering the bed roughness and entrainment ratio. For both smooth and roughened beds, a generalized relationship was obtained for estimating the conjugate depth ratio as a function of the upstream densimetric Froude number, the entrainment ratio, and the relative roughness. Moreover, various equations for calculating the maximum possible value of the relative roughness, the minimum possible value of the prejump densimetric Froude number, and the maximum possible value of the relative roughness were proposed. The minimum possible value of the conjugate depth ratio was determined. It was found that both the conjugate depth ratio  and the length of the roller zone decrease as the bed roughness increases. Moreover, as the entrainment ratio increases, the ratio  may also decrease, or may initially increase and then decrease. Finally, a relationship was obtained for estimating the minimum possible value of the obstacle height as a function of the conjugate depth ratio.
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spelling doaj.art-285340b997944c8fa3956078f9e8c6972024-01-10T08:08:27ZfasMarvdasht Branch, Islamic Azad Universityمهندسی منابع آب2008-63772423-71912017-08-01103323362436Analytical Study of the Bed Roughness and Entrainment Ratio of Saline Density Currents on Hydraulic JumpNader Barahmand0‌دانشگاه ‌آزاد ‌اسلامی، واحد لارستان، گروه مهندسی عمران، لارستان، ایرانDensity current is produced due to a density contrast with the ambient fluid. This density difference can result from dissolved solids, suspended materials, temperature, etc. Density jumps significantly influence the characteristics of the gravity currents and the ambient fluid (e.g., velocities and concentrations). In this paper, the density jump is studied analytically by considering the bed roughness and entrainment ratio. For both smooth and roughened beds, a generalized relationship was obtained for estimating the conjugate depth ratio as a function of the upstream densimetric Froude number, the entrainment ratio, and the relative roughness. Moreover, various equations for calculating the maximum possible value of the relative roughness, the minimum possible value of the prejump densimetric Froude number, and the maximum possible value of the relative roughness were proposed. The minimum possible value of the conjugate depth ratio was determined. It was found that both the conjugate depth ratio  and the length of the roller zone decrease as the bed roughness increases. Moreover, as the entrainment ratio increases, the ratio  may also decrease, or may initially increase and then decrease. Finally, a relationship was obtained for estimating the minimum possible value of the obstacle height as a function of the conjugate depth ratio.https://wej.marvdasht.iau.ir/article_2436_ed098135734f8629cd13ae3a060cd830.pdfdensity jumpambient fluidrelative roughnessentrainment ratiodensimetric froude number
spellingShingle Nader Barahmand
Analytical Study of the Bed Roughness and Entrainment Ratio of Saline Density Currents on Hydraulic Jump
مهندسی منابع آب
density jump
ambient fluid
relative roughness
entrainment ratio
densimetric froude number
title Analytical Study of the Bed Roughness and Entrainment Ratio of Saline Density Currents on Hydraulic Jump
title_full Analytical Study of the Bed Roughness and Entrainment Ratio of Saline Density Currents on Hydraulic Jump
title_fullStr Analytical Study of the Bed Roughness and Entrainment Ratio of Saline Density Currents on Hydraulic Jump
title_full_unstemmed Analytical Study of the Bed Roughness and Entrainment Ratio of Saline Density Currents on Hydraulic Jump
title_short Analytical Study of the Bed Roughness and Entrainment Ratio of Saline Density Currents on Hydraulic Jump
title_sort analytical study of the bed roughness and entrainment ratio of saline density currents on hydraulic jump
topic density jump
ambient fluid
relative roughness
entrainment ratio
densimetric froude number
url https://wej.marvdasht.iau.ir/article_2436_ed098135734f8629cd13ae3a060cd830.pdf
work_keys_str_mv AT naderbarahmand analyticalstudyofthebedroughnessandentrainmentratioofsalinedensitycurrentsonhydraulicjump