Upper Bounds for the Complex Growth Rate of a Disturbance in Ferrothermohaline Convection

It is proved analytically that the complex growth rate σ= σr+iσi (σr and σi are the real and imaginary parts of σ, respectively) of an arbitrary oscillatory motion of neutral or growing amplitude in ferrothermohaline convection in a ferrofluid layer for the case of free boundaries is located inside...

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Main Authors: Ram Kaka, Prakash Jyoti, Kumari Kultaran, Kumar Pankaj
Format: Article
Language:English
Published: Sciendo 2022-03-01
Series:Studia Geotechnica et Mechanica
Subjects:
Online Access:https://doi.org/10.2478/sgem-2022-0005
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author Ram Kaka
Prakash Jyoti
Kumari Kultaran
Kumar Pankaj
author_facet Ram Kaka
Prakash Jyoti
Kumari Kultaran
Kumar Pankaj
author_sort Ram Kaka
collection DOAJ
description It is proved analytically that the complex growth rate σ= σr+iσi (σr and σi are the real and imaginary parts of σ, respectively) of an arbitrary oscillatory motion of neutral or growing amplitude in ferrothermohaline convection in a ferrofluid layer for the case of free boundaries is located inside a semicircle in the right half of the σrσi-plane, whose center is at the origin and radius = Rs[1−M1′(1−1M5)]Pr′,{\rm{radius}}\, = \,\sqrt {{{{R_s}\left[{1 - M_1^{'}\left({1 - {1 \over {{M_5}}}} \right)} \right]} \over {P_r^{'}}}}, where Rs is the concentration Rayleigh number, Pr′ is the solutal Prandtl number, M1′ is the ratio of magnetic flux due to concentration fluctuation to the gravitational force, and M5 is the ratio of concentration effect on magnetic field to pyromagnetic coefficient. Further, bounds for the case of rigid boundaries are also derived separately.
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spelling doaj.art-7fbfd78119a4405db67ac68cf0f58da72022-12-22T02:41:00ZengSciendoStudia Geotechnica et Mechanica2083-831X2022-03-0144211412210.2478/sgem-2022-0005Upper Bounds for the Complex Growth Rate of a Disturbance in Ferrothermohaline ConvectionRam Kaka0Prakash Jyoti1Kumari Kultaran2Kumar Pankaj3Department of Mathematics and Statistics, Himachal Pradesh University, Summer Hill, Shimla171005, IndiaDepartment of Mathematics and Statistics, Himachal Pradesh University, Summer Hill, Shimla171005, IndiaDepartment of Mathematics and Statistics, Himachal Pradesh University, Summer Hill, Shimla171005, IndiaPankaj Kumar, Department of Mathematics, Central University of Himachal Pradesh, Dharamshala, District Kangra-176215, IndiaIt is proved analytically that the complex growth rate σ= σr+iσi (σr and σi are the real and imaginary parts of σ, respectively) of an arbitrary oscillatory motion of neutral or growing amplitude in ferrothermohaline convection in a ferrofluid layer for the case of free boundaries is located inside a semicircle in the right half of the σrσi-plane, whose center is at the origin and radius = Rs[1−M1′(1−1M5)]Pr′,{\rm{radius}}\, = \,\sqrt {{{{R_s}\left[{1 - M_1^{'}\left({1 - {1 \over {{M_5}}}} \right)} \right]} \over {P_r^{'}}}}, where Rs is the concentration Rayleigh number, Pr′ is the solutal Prandtl number, M1′ is the ratio of magnetic flux due to concentration fluctuation to the gravitational force, and M5 is the ratio of concentration effect on magnetic field to pyromagnetic coefficient. Further, bounds for the case of rigid boundaries are also derived separately.https://doi.org/10.2478/sgem-2022-0005linear stabilityferrofluidoscillatory motionsferrothermohaline convection
spellingShingle Ram Kaka
Prakash Jyoti
Kumari Kultaran
Kumar Pankaj
Upper Bounds for the Complex Growth Rate of a Disturbance in Ferrothermohaline Convection
Studia Geotechnica et Mechanica
linear stability
ferrofluid
oscillatory motions
ferrothermohaline convection
title Upper Bounds for the Complex Growth Rate of a Disturbance in Ferrothermohaline Convection
title_full Upper Bounds for the Complex Growth Rate of a Disturbance in Ferrothermohaline Convection
title_fullStr Upper Bounds for the Complex Growth Rate of a Disturbance in Ferrothermohaline Convection
title_full_unstemmed Upper Bounds for the Complex Growth Rate of a Disturbance in Ferrothermohaline Convection
title_short Upper Bounds for the Complex Growth Rate of a Disturbance in Ferrothermohaline Convection
title_sort upper bounds for the complex growth rate of a disturbance in ferrothermohaline convection
topic linear stability
ferrofluid
oscillatory motions
ferrothermohaline convection
url https://doi.org/10.2478/sgem-2022-0005
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AT kumarikultaran upperboundsforthecomplexgrowthrateofadisturbanceinferrothermohalineconvection
AT kumarpankaj upperboundsforthecomplexgrowthrateofadisturbanceinferrothermohalineconvection