International Journal of Theoretical and Applied Multiscale Mechanics http://www.inderscience.com/browse/index.php?journalID=293&year=2012&vol=2&issue=3 Inderscience Publishers Ltd en-uk support@inderscience.com International Journal of Theoretical and Applied Multiscale Mechanics 1755-9995 1756-0004 © 2013 Inderscience Enterprises Ltd. © 2012 Inderscience Publishers Ltd editor@inderscience.com https://www.inderscience.com/images/files/coverImgs/ijtamm_scoverijtamm.jpg http://www.inderscience.com/browse/index.php?journalID=293&year=2012&vol=2&issue=3 http://www.inderscience.com/link.php?id=49932 A linear analysis of capillary instability with radial electric field is carried out using viscous potential flow theory. In viscous potential flow, the viscous term in the Navier-Stokes equation vanishes as vorticity is zero but viscosity is not zero. Viscosity enters through normal stress balance in viscous potential flow theory and the tangential stresses are not considered. The effect of gravity and free surface charges at the interface are neglected. A dispersion relation is derived for the case of radially imposed electric field and stability is discussed in terms of various parameters such as Ohnesorge number, permittivity ratio, etc. A condition for neutral stability is obtained and it is given in terms of critical value of electric field. It is observed that the radial electric field has dual effect on the stability of the system corresponding to the values of conductivities and permittivities of the fluids. Viscous potential flow analysis of capillary instability with radial electric field
M.K. Awasthi; G.S. Agrawal
International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 3 (2012) pp. 185 - 197
A linear analysis of capillary instability with radial electric field is carried out using viscous potential flow theory. In viscous potential flow, the viscous term in the Navier-Stokes equation vanishes as vorticity is zero but viscosity is not zero. Viscosity enters through normal stress balance in viscous potential flow theory and the tangential stresses are not considered. The effect of gravity and free surface charges at the interface are neglected. A dispersion relation is derived for the case of radially imposed electric field and stability is discussed in terms of various parameters such as Ohnesorge number, permittivity ratio, etc. A condition for neutral stability is obtained and it is given in terms of critical value of electric field. It is observed that the radial electric field has dual effect on the stability of the system corresponding to the values of conductivities and permittivities of the fluids.

]]> 10.1504/IJTAMM.2012.049932 International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 3 (2012) pp. 185 - 197 M.K. Awasthi; G.S. Agrawal Department of Mathematics, Indian Institute of Technology Roorkee, Roorkee, 247667, India. ' Department of Mathematics, Indian Institute of Technology Roorkee, Roorkee, 247667, India viscous potential flow capillary instability radial electric field interfacial flows normal stresses viscosity 2012-10-19T23:20:50-05:00 © 2013 Inderscience Enterprises Ltd. 2 3 185 197 2012-10-19T23:20:50-05:00 http://www.inderscience.com/link.php?id=49931 The double-diffusive convection in a horizontal nanofluid saturated porous layer is studied analytically using a Brinkman-Darcy model. The model used for nanofluid includes the effects of Brownian motion and thermophoresis. The linear stability theory is employed to obtain the condition for the onset of convection. The effect of solute Rayleigh number, Soret parameter, Dufour parameter, Lewis number, nanoparticle Rayleigh number, nanoparticle Lewis number, modified particle-density increment parameter, modified diffusivity ratio, Darcy number and the porosity parameter have been analysed on the onset of convection. The sufficient conditions for the non-existence of overstability are also obtained. The onset of convection in a binary nanofluid saturated porous layer
Dhananjay Yadav; G.S. Agrawal; Rama Bhargava
International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 3 (2012) pp. 198 - 224
The double-diffusive convection in a horizontal nanofluid saturated porous layer is studied analytically using a Brinkman-Darcy model. The model used for nanofluid includes the effects of Brownian motion and thermophoresis. The linear stability theory is employed to obtain the condition for the onset of convection. The effect of solute Rayleigh number, Soret parameter, Dufour parameter, Lewis number, nanoparticle Rayleigh number, nanoparticle Lewis number, modified particle-density increment parameter, modified diffusivity ratio, Darcy number and the porosity parameter have been analysed on the onset of convection. The sufficient conditions for the non-existence of overstability are also obtained.

]]> 10.1504/IJTAMM.2012.049931 International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 3 (2012) pp. 198 - 224 Dhananjay Yadav; G.S. Agrawal; Rama Bhargava Department of Mathematics, Indian Institute of Technology Roorkee, Roorkee, 247667, India. ' Department of Computer Science, Manglayatan University, Aligarh, 202145, India. ' Department of Mathematics, Indian Institute of Technology Roorkee, Roorkee, 247667, India nanofluids double diffusive convection Brownian motion thermophoresis porous medium Galerkin method nanotechnology saturated porous layers nanoparticles 2012-10-19T23:20:50-05:00 © 2013 Inderscience Enterprises Ltd. 2 3 198 224 2012-10-19T23:20:50-05:00 http://www.inderscience.com/link.php?id=49944 Improvements in the fabrication capability have given rise to mini/micro systems for heat and mass transfer operations. The motion of uniform/oscillating menisci or air-plug/liquid slug inside such systems (i.e., capillaries/channels) is a challenging hydrodynamic problem that is relevant in many interesting practical applications. Understanding the hydrodynamics of such flows will help us in manipulating the performance parameters, which will further improve the efficiency of these systems. The present paper is an attempt to review the experimental, theoretical/analytical, and modelling methodologies applied to capillaries to predict these properties. Out of the different flow patterns inside the capillaries, oscillating slug flow has been reviewed intensely. In general, flow properties are well understood and predicted for fully formed unidirectional Taylor bubbles in circular as well as rectangular channels. However, the effect of impurities on interfacial tension cannot be fully accounted so far. In addition, there is still uncertainty about the size of bubbles and slugs, while there is little literature available for oscillating slug flows/meniscus. In view of the state of art on such flows, further recommendations have been made for future research direction to explore various hydrodynamic characteristics. Hydrodynamics of oscillating slug flow inside mini channels: a state of art review
Ajay Tripathi; S.K. Agrawal
International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 3 (2012) pp. 225 - 254
Improvements in the fabrication capability have given rise to mini/micro systems for heat and mass transfer operations. The motion of uniform/oscillating menisci or air-plug/liquid slug inside such systems (i.e., capillaries/channels) is a challenging hydrodynamic problem that is relevant in many interesting practical applications. Understanding the hydrodynamics of such flows will help us in manipulating the performance parameters, which will further improve the efficiency of these systems. The present paper is an attempt to review the experimental, theoretical/analytical, and modelling methodologies applied to capillaries to predict these properties. Out of the different flow patterns inside the capillaries, oscillating slug flow has been reviewed intensely. In general, flow properties are well understood and predicted for fully formed unidirectional Taylor bubbles in circular as well as rectangular channels. However, the effect of impurities on interfacial tension cannot be fully accounted so far. In addition, there is still uncertainty about the size of bubbles and slugs, while there is little literature available for oscillating slug flows/meniscus. In view of the state of art on such flows, further recommendations have been made for future research direction to explore various hydrodynamic characteristics.

]]> 10.1504/IJTAMM.2012.049944 International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 3 (2012) pp. 225 - 254 Ajay Tripathi; S.K. Agrawal Department of Mechanical Engineering, Jaypee University of Engineering and Technology, Guna, 473226, Guna, India. ' Department of Mechanical Engineering, National Institute of Technology Allahabad, 211004, Allahabad, India meniscus shape meniscus dynamics oscillating slug flow hydrodynamics Taylor bubbles mini channels micro channels pulsating heat pipes mass transfer heat transfer 2012-10-19T23:20:50-05:00 © 2013 Inderscience Enterprises Ltd. 2 3 225 254 2012-10-19T23:20:50-05:00 http://www.inderscience.com/link.php?id=49965 This paper presents differential evolution algorithm technique to design a rectangular composite plate by optimising the laminate stacking sequence whose aim is to maximise the buckling load capability without any failure at ply level. In this paper, Tsai Hill failure criterion is used to compute with the failure index and reserve factors for each ply. The optimised results obtained by implementing the differential evolution algorithm for three different load cases are compared with Msc-Nastran FEA solver results. The usage of differential evolution (DE) algorithm for laminate stacking sequence optimisation to maximise buckling load capability is discussed in this paper. The results show that the differential evolution algorithm technique is an effective optimisation tool to determine both the accurate laminate stacking sequence of composite panel. We also notice that the efficiency corroborates the results. Buckling design optimisation of composite laminated plates using differential evolution algorithm approach
M.V.A. Raju Bahubalendruni; T.V. Srinivasa Rao; Venkataramana Mantha
International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 3 (2012) pp. 255 - 270
This paper presents differential evolution algorithm technique to design a rectangular composite plate by optimising the laminate stacking sequence whose aim is to maximise the buckling load capability without any failure at ply level. In this paper, Tsai Hill failure criterion is used to compute with the failure index and reserve factors for each ply. The optimised results obtained by implementing the differential evolution algorithm for three different load cases are compared with Msc-Nastran FEA solver results. The usage of differential evolution (DE) algorithm for laminate stacking sequence optimisation to maximise buckling load capability is discussed in this paper. The results show that the differential evolution algorithm technique is an effective optimisation tool to determine both the accurate laminate stacking sequence of composite panel. We also notice that the efficiency corroborates the results.

]]> 10.1504/IJTAMM.2012.049965 International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 3 (2012) pp. 255 - 270 M.V.A. Raju Bahubalendruni; T.V. Srinivasa Rao; Venkataramana Mantha CoE Composite Structures, ERS-OEM-ME-Aero, HCL Technologies Limited, #3,Surya Spphire, Electronic City Phase-1, Bangalore-560100, India. ' CoE Composite Structures, ERS-OEM-ME-Aero, HCL Technologies Limited, #3,Surya Spphire, Electronic City Phase-1, Bangalore-560100, India. ' CoE Composite Structures, Aero-structures Group, ERS-OEM-ME-Aero, HCL Technologies Limited, #3,Surya Spphire, Electronic City Phase-1, Bangalore-560100, India composite plates laminated plates buckling design optimisation differential evolution laminate stacking sequences Tsai Hill failure criterion FEA finite element analysis buckling load capability 2012-10-19T23:20:50-05:00 © 2013 Inderscience Enterprises Ltd. 2 3 255 270 2012-10-19T23:20:50-05:00