Nikos Savva

Nikos Savva previously held the position of tenured Lecturer at the School of Mathematics at Cardiff University. He also held the post of post-doctoral research associate at the Chemical Engineering Department of Imperial College London and held a visiting appointment at the Université Libre de Bruxelles. He holds a PhD in Applied Mathematics from the Massachusetts Institute of Technology, a BSc in Applied Mathematics Engineering and Physics from the University of Wisconsin-Madison, and a Fellowship from the UK's Higher Education Academy. His research interests lie at the interface between applied mathematics and theoretical engineering, with particular focus on multiscale flows pertaining to wetting hydrodynamics. Much of his work to date combines analytical and numerical approaches in order to elucidate the influence of substrate heterogeneities and other complexities on contact line dynamics, and how these may be used for controlling the actuation of droplets in applications.

Research interests

• Complex flows: wetting phenomena;  investigation of free-surface flows supported on substrates influenced by  substrate morphology (chemical and topographical), vibrations or other effects, such as the presence of a turbulent gas; dynamics of curved, unsupported liquid  films; liquid jets.
• Applied mathematical modelling: singular  perturbation methods and matched asymptotics; dynamical systems and bifurcation  analysis; stochastic processes; physical resolution of singularities in  mathematical models.
• Numerical methods: accurate and efficient  numerical schemes for nonlinear PDEs via spectrally accurate methods; improved  numerical schemes for dynamic density functional theory; numerical  continuation.
• Statistical mechanics of inhomogeneous fluids: analytical approaches to density functional theory; extensions to far-from-equilibrium dynamics; formalism.

Selected Publications

1. Savva, N., Groves, D. and Kalliadasis, S. 2019. Droplet dynamics on chemically heterogeneous substrates. Journal of Fluid Mechanics 859, pp. 321-361. (10.1017/jfm.2018.758)
2. Savva, N., Rednikov, A. and Colinet, P. 2017. Asymptotic analysis of the evaporation dynamics of partially wetting droplets. Journal of Fluid Mechanics 824, pp. 574-623. (10.1017/jfm.2017.330)
3. Nold, A.et al. 2017. Pseudospectral methods for density functional theory in bounded and unbounded domains. Journal of Computational Physics 334, pp. 639-664. (10.1016/j.jcp.2016.12.023)
4. Pradas, M.et al. 2016. Dynamics of fattening and thinning 2D sessile droplets. Langmuir 32(19), pp. 4736-4745. (10.1021/acs.langmuir.6b00256)
5. Sibley, D. N.et al. 2015. A comparison of slip, disjoining pressure, and interface formation models for contact line motion through asymptotic analysis of thin two-dimensional droplet spreading. Journal of Engineering Mathematics 94(1), pp. 19-41. (10.1007/s10665-014-9702-9)
6. Yatsyshin, P., Savva, N. and Kalliadasis, S. 2015. Density functional study of condensation in capped capillaries. Journal of Physics: Condensed Matter 27(27), article number: 275104. (10.1088/0953-8984/27/27/275104)
7. Yatsyshin, P., Savva, N. and Kalliadasis, S. 2015. Wetting of prototypical one- and two-dimensional systems: Thermodynamics and density functional theory. Journal of Chemical Physics 142(3), article number: 34708. (10.1063/1.4905605)
8. Savva, N. and Kalliadasis, S. 2014. Low-frequency vibrations of two-dimensional droplets on heterogeneous substrates. Journal of Fluid Mechanics 754, pp. 515-549. (10.1017/jfm.2014.409)
9. Vellingiri, R.et al. 2013. Dynamics of a liquid film sheared by a co-flowing turbulent gas. International Journal of Multiphase Flow 56, pp. 93-104. (10.1016/j.ijmultiphaseflow.2013.05.011)
10. Sibley, D. N.et al. 2013. On the moving contact line singularity: Asymptotics of a diffuse-interface model. The European Physical Journal E 36(3), article number: 26. (10.1140/epje/i2013-13026-y)
11. Yatsyshin, P., Savva, N. and Kalliadasis, S. 2013. Geometry-induced phase transition in fluids: Capillary prewetting. Physical Review E 87(2), article number: 20402. (10.1103/PhysRevE.87.020402)
12. Goddard, B. D.et al. 2013. Inertia and hydrodynamic interactions in dynamical density functional theory. Presented at: European Conference on Complex Systems 2012, Brussels, SeptemberProceedings of the European Conference on Complex Systems 2012. Springer Proceedings in Complexity pp. 999-10004., (10.1007/978-3-319-00395-5_120)
13. Goddard, B. D.et al. 2013. Unification of dynamic density functional theory for colloidal fluids to include inertia and hydrodynamic interactions: derivation and numerical experiments. Journal of Physics: Condensed Matter 25(3), article number: 35101. (10.1088/0953-8984/25/3/035101)
14. Savva, N. and Kalliadasis, S. 2013. Droplet motion on inclined heterogeneous substrates. Journal of Fluid Mechanics 725, pp. 462-491. (10.1017/jfm.2013.201)
15. Sibley, D. N.et al. 2013. The contact line behaviour of solid-liquid-gas diffuse-interface models. Physics of Fluids 25(9), article number: 92111. (10.1063/1.4821288)
16. Savva, N. and Kalliadasis, S. 2012. Influence of gravity on the spreading of two-dimensional droplets over topographical substrates. Journal of Engineering Mathematics 73(1), pp. 3-16. (10.1007/s10665-010-9426-4)
17. Yatsyshin, P., Savva, N. and Kalliadasis, S. 2012. Spectral methods for the equations of classical density-functional theory: Relaxation dynamics of microscopic films. The Journal of Chemical Physics 136(12), article number: 124113. (10.1063/1.3697471)
18. Sibley, D. N., Savva, N. and Kalliadasis, S. 2012. Slip or not slip? A methodical examination of the interface formation model using two-dimensional droplet spreading on a horizontal planar substrate as a prototype system. Physics of Fluids 24(8), article number: 82105. (10.1063/1.4742895)
19. Goddard, B.et al. 2012. General Dynamical Density Functional Theory for Classical Fluids. Physical Review Letters (PRL) 109(12), article number: 120603. (10.1103/PhysRevLett.109.120603)
20. Vellingiri, R., Savva, N. and Kalliadasis, S. 2011. Droplet spreading on chemically heterogeneous substrates. Physical Review E 84(3), article number: 36305. (10.1103/PhysRevE.84.036305)
21. Savva, N. and Kalliadasis, S. 2011. Dynamics of moving contact lines: A comparison between slip and precursor film models. Europhysics Letters 94(6), article number: 64004. (10.1209/0295-5075/94/64004)
22. Savva, N., Pavliotis, G. A. and Kalliadasis, S. 2011. Contact lines over random topographical substrates. Part 2. Dynamics. Journal of Fluid Mechanics 672, pp. 384-410. (10.1017/S0022112010005987)
23. Savva, N., Pavliotis, G. A. and Kalliadasis, S. 2011. Contact lines over random topographical substrates. Part 1. Statics. Journal of Fluid Mechanics 672, pp. 358-383. (10.1017/S0022112010005975)
24. Savva, N., Kalliadasis, S. and Pavliotis, G. A. 2010. Two-Dimensional Droplet Spreading over Random Topographical Substrates. Physical Review Letters 104(8), article number: 84501. (10.1103/PhysRevLett.104.084501)
25. Savva, N. and Kalliadasis, S. 2010. Influence of spatial heterogeneities on spreading dynamics. Journal of Physics: Conference Series 216(1), article number: 12017. (10.1088/1742-6596/216/1/012017)
26. Savva, N. and Kalliadasis, S. 2009. Two-dimensional droplet spreading over topographical substrates. Physics of Fluids 21(9), article number: 92102. (10.1063/1.3223628)
27. Savva, N. and Bush, J. W. M. 2009. Viscous sheet retraction. Journal of Fluid Mechanics 626, pp. 211-240. (10.1017/S0022112009005795)
28. Constantinides, G.et al. 2009. Quantitative Impact Testing of Energy Dissipation at Surfaces. Experimental Mechanics 49(4), pp. 511-522. (10.1007/s11340-008-9198-1)
29. Margetis, D. and Savva, N. 2006. Low-frequency currents induced in adjacent spherical cells. Journal of Mathematical Physics 47(4), article number: 42902. (10.1063/1.2190333)