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A. Coherent structures in turbulent convection Turbulent convection occurs in areas ranging from atmospheres, oceans, mantles to manufacturing processes, electronic cooling, PCR as well as in day to day cooking. The heat flux in turbulent convection is critically decided by the phenomena near the hot surface. Our interest is in understanding the dynamics of the coherent structures near the hot, horizontal surface, observed as rising sheets called line plumes, and their role in transporting heat. A model to explain the observed mean plume spacings [3] and total length of plumes [2] have been built. Commonalities in the plume structure under differing conditions were detected, implying a common dynamics. Scaling laws for the dynamics of line plumes have been found recently [1]. Present research: 1. Modelling of merging plumes (PhD, A. M. Ayyappadas) 2. Investigation of velocity field near horizontal surfaces in turbulent convection (MS, Vipin, K.) 3. Settling of particles in turbulent convection (MS, Sanal Mohanan) References : 1. Gunasegarane, G. S. and Puthenveettil, B. A., Dynamics of line plumes on horizontal surfaces in turbulent convection, JFM, 749, pp 37-78, 2014 (Cover article for the journal issue). 2. Puthenveettil, B. A., Gunasegarane, G. S., Agrawal, Y. K., Schmeling, D., Bosbach, J. and Arakeri, J. H., Length of near-wall plumes in turbulent convection, JFM, 685, pp335-364, 2011. 3. Puthenveettil, B. A. and Arakeri, J. H.,Plume structure in high Rayleigh number convection, JFM, 542, pp217-249, 2005. |
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Top view of coherent structures in turbulent convection near the hot surface |
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C. Transport across membranes We investigate density driven transport across microporous membranes which occur in many biological systems, filtration, catalysis, carbon sequestration etc. Our investigations have mapped the different regimes of transport for the first time and found out scaling of mass flux in these regimes [1]. New regimes of transport where diffusion balances advection across the membrane has been discovered [2]. A theory for predicting the mean concentration profile on the surface of the membrane was developed and verified. The present research include : 1. Study of strong advective transport across the membrane and the ensuing instability of boundary layers on the membrane (PhD, P. J. Joshy) References : 1. Puthenveetil, B.A. and Arakeri, J.H., Convection due to an unstable density difference across a permeable membrane, JFM, vol 609, pp 139-170, 2008. 2. G.V.Ramareddy and Puthenveetil, B.A. The Pe~1 regime of convection across a horizontal permeable membrane, JFM, 679, pp 476-504, 2011, (Cover article for the journal issue). |
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Research Group |
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Students : PhD Gunasegarane, G. S., Joshy, P. J., Sangeeth, K., Anoop, P., Anurag Pant, A. M. Ayyappadas MS Vipin, K., Sanal Mohanan Technical staff : H. Udayakumar, Technician Baskar, Technician Laboratory : Laser velocimetry and fluorescence lab |
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Students interested in research in related areas are welcome to contact me by email.
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Surface capillary waves when a fluid layer is vertically vibrated (parametric excitation) |
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Research Interests |
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B. Interfacial phenomena Interfaces are thin boundaries between phases having an excess of free energy called the interfacial tension. Interfacial effects are important where interfacial area is large compared to the volume of the fluid as in multiphase flows, capillary phenomena, phenomena at small scales etc. Our interest includes waves, drops and bubbles, their dynamics and fragmentation. Some of the work that we have investigated include drop ejection from breakup of capillary waves[1], motion of drops on surfaces [2]. The present research include : 1. Breaking bubbles at free surface (PhD, K. Sangeeth) 2. Sedimenting drops (PhD, Anoop, P.) 3. Twisting of liquid column (PhD, Anurag Pant) References: 1. Puthenveettil,B.A. and Hopfinger, E.J., Evolution and breaking of parametrically forced capillary waves in a circular cylinder, JFM, 633, pp 355-379, 2009. 2. Puthenveettil, B. A. , Senthilkumar,V. K. and Hopfinger, E. J., Motion of drops on inclined surfaces in the inertial regime, JFM, 726, pp 26-61, 2013. (Selected for Focus on Fluids in JFM) |
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Research Alumni 1. G.V.Ramareddy, M.S., 2010, PhD student, University of Melbourne. 2. V.Senthil Kumar, M.S., 2011, Transoft International, Bangalore.
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