Investigation of the interfacial instability in a non-Boussinesq density stratified flow using linear stability theory

The main goal of this study is investigating the interfacial instability in the shear density stratified flow in non-Boussinesq regime using linear stability theory. In the current study, the pseudospectral collocation method employed Chebyshev polynomials is applied to solve two coupled eigenvalue...

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Main Authors: Ehsan Khavasi, Pouriya Amini, Javad Rahimi, Mohammad Hadi Mohammadi
Format: Article
Language:English
Published: Taylor & Francis Group 2019-01-01
Series:Cogent Engineering
Subjects:
Online Access:http://dx.doi.org/10.1080/23311916.2019.1661590
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author Ehsan Khavasi
Pouriya Amini
Javad Rahimi
Mohammad Hadi Mohammadi
author_facet Ehsan Khavasi
Pouriya Amini
Javad Rahimi
Mohammad Hadi Mohammadi
author_sort Ehsan Khavasi
collection DOAJ
description The main goal of this study is investigating the interfacial instability in the shear density stratified flow in non-Boussinesq regime using linear stability theory. In the current study, the pseudospectral collocation method employed Chebyshev polynomials is applied to solve two coupled eigenvalue equations. Using the linear stability analysis in the temporal framework, the effects of various parameters on the flow instability have been studied. Obtained results in the present paper are showing that increasing the bed slope, the flow becomes more unstable; also at R = 1, Kelvin–Helmholtz and Holmboe waves appear. Furthermore, Holmboe waves were not observed only at θ = 0. This study shows that at R ≠ 1, in addition to observing Kelvin–Helmholtz and Holmboe waves with higher growth rates, by increasing the bed slope, the growth rate and the number of Kelvin–Helmholtz modes increase. With an improved understanding of the instability mechanisms and features with including the non-Boussinesq effects, one can confirm some of the previous experimental results and offer new indications to observations that have not been fully explained. In designing laboratory experiments to observe Holmboe waves and estimating their wavelengths and phase speeds the results of present paper are also could be useful.
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spelling doaj.art-5e8e6690f8794987a1cfe916c2c7ac0c2023-09-02T18:30:44ZengTaylor & Francis GroupCogent Engineering2331-19162019-01-016110.1080/23311916.2019.16615901661590Investigation of the interfacial instability in a non-Boussinesq density stratified flow using linear stability theoryEhsan Khavasi0Pouriya Amini1Javad Rahimi2Mohammad Hadi Mohammadi3University Of ZanjanGuilan UniversityGuilan UniversityGuilan UniversityThe main goal of this study is investigating the interfacial instability in the shear density stratified flow in non-Boussinesq regime using linear stability theory. In the current study, the pseudospectral collocation method employed Chebyshev polynomials is applied to solve two coupled eigenvalue equations. Using the linear stability analysis in the temporal framework, the effects of various parameters on the flow instability have been studied. Obtained results in the present paper are showing that increasing the bed slope, the flow becomes more unstable; also at R = 1, Kelvin–Helmholtz and Holmboe waves appear. Furthermore, Holmboe waves were not observed only at θ = 0. This study shows that at R ≠ 1, in addition to observing Kelvin–Helmholtz and Holmboe waves with higher growth rates, by increasing the bed slope, the growth rate and the number of Kelvin–Helmholtz modes increase. With an improved understanding of the instability mechanisms and features with including the non-Boussinesq effects, one can confirm some of the previous experimental results and offer new indications to observations that have not been fully explained. In designing laboratory experiments to observe Holmboe waves and estimating their wavelengths and phase speeds the results of present paper are also could be useful.http://dx.doi.org/10.1080/23311916.2019.1661590interfacial instabilitylinear stability analysisstratified shear flowsnon-boussinesq
spellingShingle Ehsan Khavasi
Pouriya Amini
Javad Rahimi
Mohammad Hadi Mohammadi
Investigation of the interfacial instability in a non-Boussinesq density stratified flow using linear stability theory
Cogent Engineering
interfacial instability
linear stability analysis
stratified shear flows
non-boussinesq
title Investigation of the interfacial instability in a non-Boussinesq density stratified flow using linear stability theory
title_full Investigation of the interfacial instability in a non-Boussinesq density stratified flow using linear stability theory
title_fullStr Investigation of the interfacial instability in a non-Boussinesq density stratified flow using linear stability theory
title_full_unstemmed Investigation of the interfacial instability in a non-Boussinesq density stratified flow using linear stability theory
title_short Investigation of the interfacial instability in a non-Boussinesq density stratified flow using linear stability theory
title_sort investigation of the interfacial instability in a non boussinesq density stratified flow using linear stability theory
topic interfacial instability
linear stability analysis
stratified shear flows
non-boussinesq
url http://dx.doi.org/10.1080/23311916.2019.1661590
work_keys_str_mv AT ehsankhavasi investigationoftheinterfacialinstabilityinanonboussinesqdensitystratifiedflowusinglinearstabilitytheory
AT pouriyaamini investigationoftheinterfacialinstabilityinanonboussinesqdensitystratifiedflowusinglinearstabilitytheory
AT javadrahimi investigationoftheinterfacialinstabilityinanonboussinesqdensitystratifiedflowusinglinearstabilitytheory
AT mohammadhadimohammadi investigationoftheinterfacialinstabilityinanonboussinesqdensitystratifiedflowusinglinearstabilitytheory