Instability Analysis of Gyrotactic Microorganisms: A Combined Effect of High-Frequency Vertical Vibration and Porous Media

2014 ◽  
Vol 102 (2) ◽  
pp. 153-165 ◽  
Author(s):  
Virendra Kumar ◽  
Y. D. Sharma
Keyword(s):  
Porous Media ◽  
High Frequency ◽  
Vertical Vibration ◽  
Combined Effect ◽  
Instability Analysis ◽  
Gyrotactic Microorganisms

scholarly journals A Computational Analysis of Two-Phase Casson Nanofluid Passing a Stretching Sheet Using Chemical Reactions and Gyrotactic Microorganisms

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Zulqurnain Sabir ◽  
Rizwan Akhtar ◽  
Zhu Zhiyu ◽  
Muhammad Umar ◽  
Ali Imran ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Porous Media ◽  
Nusselt Number ◽  
Chemical Reactions ◽  
Stretching Sheet ◽  
Field Parameter ◽  
Two Phase ◽  
Gyrotactic Microorganisms ◽  
Magnetic Field Parameter ◽  
Casson Nanofluid

In this study, an attempt is made to explore the two-phase Casson nanofluid passing through a stretching sheet along a permeable surface with the effects of chemical reactions and gyrotactic microorganisms. By utilizing the strength of similarity transforms the governing PDEs are transformed into set of ODEs. The resulting equations are handled by using a proficient numerical scheme known as the shooting technique. Authenticity of numerical outcomes is established by comparing the achieved results with the MATLAB built-in solver bvp4c. The numerical outcomes for the reduced Nusselt number and Sherwood number are exhibited in the tabular form, while the variations of some crucial physical parameters on the velocity, temperature, and concentration profiles are demonstrated graphically. It is observed that Local Nusselt number rises with the enhancement in the magnetic field parameter, the porous media parameter, and the chemical reactions, while magnetic field parameter along with porous media parameter retards the velocity profile.

Instability analysis of the surface of molten metal under high frequency electromagnetic fields

2002 ◽  
Vol 16 (1-2) ◽  
pp. 43-55
Author(s):  
Mitsuhiro Yoshida ◽  
Katsuaki Morita ◽  
Chie Kuwada ◽  
Takahiko Tanahashi
Keyword(s):  
Molten Metal ◽  
Electromagnetic Fields ◽  
High Frequency ◽  
Instability Analysis

In Situ Measurement of Ground Vibration Induced by Inter-City Express Train

2012 ◽  
Vol 204-208 ◽  
pp. 502-507 ◽  
Author(s):  
Quan Min Liu ◽  
Xun Zhang ◽  
Zhi Jun Zhang ◽  
Xiao Zhen Li
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Ground Vibration ◽  
Vertical Vibration ◽  
Test Results ◽  
Low Frequency Vibration ◽  
Express Train ◽  
Environmental Vibration ◽  
Logarithmic Relationship

On the basis of the measured ground borne vibration of some inter-city express railway viaduct, test results analysis shows that: the test environmental vibration is under the limit set by standard of environmental vibration in urban area; whether transverse or vertical vibration, a rapid attenuation of the peak acceleration with the distance to the up-track center is observed, however the vibration at 7.5m appears to be amplified; the ground vibration with the distance conforms to a logarithmic relationship; the horizontal ground vibration at 7.5m caused by the elevated rail transit is larger 3.6cm/s2 than the vertical vibration; low-frequency vibration transfers farther than high frequency vibration; the eccentric effect of two-track viaduct is obvious.

Stability of Bioconvection in Suspensions of Gyrotactic Microorganisms in Porous Media

2002 ◽  
Author(s):  
A. V. Kuznetsov ◽  
A. A. Avramenko
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Saturated Porous Medium ◽  
Critical Value ◽  
Numerical Results ◽  
Velocity Fluctuations ◽  
Gyrotactic Microorganisms ◽  
Upward Direction ◽  
Upward Velocity ◽  
Fluid Saturated Porous Medium

In this paper, a model of bioconvection in a suspension of gyrotactic motile microorganisms in a fluid saturated porous medium is suggested. The microorganisms considered in this paper are heavier than water and gyrotactic behavior results in their swimming towards the regions of most rapid downflow. Because of that, the regions of downflow become denser than the regions of upflow. Buoyancy increases the upward velocity in the regions of upflow and downward velocity in the regions of downflow, thus enhancing the velocity fluctuations. The experiments performed by Kessler (1986) and the numerical results of Kuznetsov and Jiang (2001) indicate that if the permeability of porous medium is sufficiently small it will prevent the development of convection instability. However, for practical purposes, in order to maximize the flux of the cells in the upward direction it is desirable to have the permeability of the porous medium as high as possible. The aim of this paper is to investigate the value of critical permeability. If permeability is smaller than this critical value bioconvection does not occur and microorganisms simply swim in the upward direction.

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