Abstract
The equations governing the dynamics of a periodically driven micro-spheroid in an unsteady viscous fluid at low Reynolds number are derived. Its oscillation properties in the presence/absence of memory forces are reported. The core part of the derivation is a perturbation analysis of motion of a sphere. The calculated solutions match with those available in the literature in the limiting case of a sphere. The dependence of the solutions on shape (\(\alpha \)), free oscillation frequency (\(\omega _0\)) and particle–fluid density ratio (\(d_r\)) is calculated. The maximum amplitude of the oscillations of an oblate spheroid is greater than that of a prolate spheroid, showing that the velocity disturbance for an oblate spheroid is higher in the presence/absence of the memory force. The increase in \(\alpha \) leads to the enhancement(reduction) of amplitude peaks in the case of the oblate (prolate) spheroid in the presence and more dominantly in the absence of the force. There is also a reduction in the amplitude of spheroid oscillations of many multiples due to the presence of the memory force. Stronger oscillation variations are observed on changing \(\omega _0\) or \(d_r\) compared to \(\alpha .\) The variations of the value of the phase are similar for both the spheroids on varying \(\omega _0\) and \(d_r\), whereas they are reversed on varying \(\alpha .\) The linear scaling of amplitude on \(\alpha \) observed for the spheroids may give insight into the physics, especially regarding the quantum of velocity disturbances due to particle size. The slopes are high in the absence of the force, confirming that the presence of the force increases the resistance of spheroid motion, largely. The dependencies of oscillations on the parameters can be utilized for better separation of particles or for characterizing the suspension. The novelty of the problem and its analytical solutions might have value as tests in software for more complicated and realistic systems and hence strikes a good balance between complication and tractability.
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References
Abbad, M., Souhar, M., Caballina, O.: Note on the memory force on a slightly eccentric fluid spheroid in unsteady creeping flows. Phys. Fluids 18(1), 013301 (2006). https://doi.org/10.1063/1.2162468
Asokan, K., Kumar, C.V.A., Dasan, J., Radhakrishnan, K., Kumar, K.S., Ramamohan, T.R.: Review of chaos in the dynamics and rheology of suspensions of orientable particles in simple shear flow subject to an external periodic force. J. Non-Newton. Fluid Mech. 129(3), 128–142 (2005). https://doi.org/10.1016/j.jnnfm.2005.06.003
Basset, A.B.: On the motion of a sphere in a viscous liquid. Philos. Trans. R. Soc. Lond. (A) 179, 43–63 (1888). https://doi.org/10.1098/rsta.1888.0003
Candelier, F., Angilella, J.R., Souhar, M.: On the effect of inertia and history forces on the slow motion of a spherical solid or gaseous inclusion in a solid-body rotation flow. J. Fluid Mech. 545, 113–139 (2005). https://doi.org/10.1017/S0022112005006877
Dabade, V., Marath, N.K., Subramanian, G.: The effect of inertia on the orientation dynamics of anisotropic particles in simple shear flow. J. Fluid Mech. 791, 631–703 (2016). https://doi.org/10.1017/jfm.2016.14
Hassan, H.K., Stepanyants, Y.A.: Resonance properties of forced oscillations of particles and gaseous bubble in a viscous fluid at small Reynolds numbers. Phys. Fluids 29(1), 101703 (2017). https://doi.org/10.1063/1.5002152
Hassan, H.K., Ostrovsky, L.A., Stepanyants, Y.A.: Particle dynamics in a viscous fluid under the action of acoustic radiation force. Interdiscip. J. Discontin. Nonlinearity Complex. 6(3), 317–327 (2017). https://doi.org/10.5890/DNC.2017.09.006
Klepper, D., Kolenkow, R.: An Introduction to Mechanics. Cambridge University Press, Cambridge (2014)
Kumar, C.V.A., Ramamohan, T.R.: New class I intermittency in the dynamics of periodically forced spheroids in simple shear flow. Phys. Lett. A 227(1–2), 72–78 (1997). https://doi.org/10.1016/S0375-9601(97)00030-3
Kumar, C.V.A., Ramamohan, T.R.: Controlling chaotic dynamics of periodically forced spheroids in simple shear flow: results for an example of a potential application. Sadhana 23(2), 131–149 (1998). https://doi.org/10.1007/BF02745678
Kumar, C.V.A., Kumar, K.S., Ramamohan, T.R.: Chaotic dynamics of periodically forced spheroids in simple shear flow with potential application to particle separation. Rheol. Acta 34(5), 504–511 (1995). https://doi.org/10.1007/BF00396563
Lawrence, C.J., Weinbaum, S.: The force on an axisymmetric body in linearized, time dependent motion: a new memory term. J. Fluid Mech. 171, 209–218 (1986). https://doi.org/10.1017/S0022112086001428
Lawrence, C.J., Weinbaum, S.: The unsteady force on a body at low Reynolds number; the axisymmetric motion of a spheroid. J. Fluid Mech. 189, 463–489 (1988). https://doi.org/10.1017/S0022112088001107
Madhukar, K., Kumar, P.V., Ramamohan, T.R., Shivakumara, I.S.: Dynamics and ’normal stress’ evaluation of dilute suspensions of periodically forced prolate spheroids in a quiescent Newtonian fluid at low Reynolds numbers. Sadhana 35(6), 659 (2010). https://doi.org/10.1007/s12046-010-0050-9
Marath, N.K., Subramanian, G.: The inertial orientation dynamics of anisotropic particles in planar linear flows. J. Fluid Mech. 844, 357–402 (2018). https://doi.org/10.1017/jfm.2018.184
Ostrovsky, L.A., Stepanyants, Y.A.: Dynamics of particles and bubbles under the action of acoustic radiation force. In: Edelman, M., Macau, E.E.N., Sanjuan, M.A.F. (eds.) Chaotic, Fractional, and Complex Dynamics: New Insights and Perspectives. Springer, Cham (2018)
Ouellette, J.: Smart fluids move into the marketplace: magneto- and electrorheological fluids find new uses. Ind. Phys. (Am. Inst. Phys.) 9(6), 14–17 (2004)
Ramamohan, T.R., Shivakumara, I.S., Madhukar, K.: The dynamics and rheology of a dilute suspension of periodically forced neutrally buoyant spherical particles in a quiescent Newtonian fluid at low Reynolds numbers. Fluid Dyn. Res. 43(4), 045–502 (2011). https://doi.org/10.1088/0169-5983/43/4/045502
Singh, J., Kumar, C.V.A.: Dynamics of a periodically forced spheroid in a quiescent fluid in the limit of low reynolds numbers. Rheol. Acta 58, 709–18 (2019). https://doi.org/10.1007/s00397-019-01169-5
Stepanyants, Y.A., Yeoh, G.H.: Particle and bubble dynamics in a creeping flow. Eur. J. Mech. B/Fluids 28(5), 619–629 (2009). https://doi.org/10.1016/j.euromechflu.2009.04.004
Stepanyants, Y.A., Yeoh, G.H.: Nanoparticle dynamics in a viscous fluid at small Reynolds numbers. In: Proceedings of the 6th Australasian Congress on Applied Mechanics, Engineers Australia, Perth, Australia, 10, p. 868 (2010)
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Singh, J., Kumar, C.V.A. Oscillations of a periodically forced slightly eccentric spheroid in an unsteady viscous flow at low Reynolds numbers. Theor. Comput. Fluid Dyn. 35, 1–15 (2021). https://doi.org/10.1007/s00162-020-00547-7
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DOI: https://doi.org/10.1007/s00162-020-00547-7