Droplet Impact and Spreading on Inclined Surfaces.

Introducing surface inclination in the case of droplet impact on solid substrates results in complicated dynamics post impact. The present work investigates the dynamics involved in the spreading phase of the droplet on inclined substrates. Experiments are conducted with water droplets impinging on inclined dry solid substrates with varying wettability values.

A fully coupled hybrid lattice Boltzmann and finite difference method-based study of transient electrokinetic flows.

Transient electrokinetic (EK) flows involve the transport of conductivity gradients developed as a result of mixing of ionic species in the fluid, which in turn is affected by the electric field applied across the channel. The presence of three different coupled equations with corresponding different time scales makes it difficult to model the problem using the lattice Boltzmann method (LBM). The present work aims to develop a hybrid LBM and finite difference method (FDM)-based model which can be used to study the electro-osmotic flows (EOFs) and the onset of EK instabilities using an Ohmic model, where fluid and conductivity transport are solved using LBM and the electric field is solved using FDM.

Capillary Displacement of Viscous Liquids in Geometries with Axial Variations.

Axial variations in geometry and presence of viscous displaced fluid are known to alter the diffusive-dynamics of capillary imbibition of a wetting liquid. We here show that the coupled effect of axially varying capillary geometry and finite viscosity of the displaced fluid can lead to significant variations in both short and long time dynamics of imbibition. Based on a theoretical model and lattice Boltzmann simulations, we analyze capillary displacement of a viscous liquid in straight and diverging capillaries.

Molecular dynamics simulations of nanoscale and sub-nanoscale friction behavior between graphene and a silicon tip: analysis of tip apex motion.

A sliding object on a crystal surface with a nanoscale contact will always experience stick-slip movement. However, investigation of the slip motion itself is rarely performed due to the short slip duration. In this study, we performed molecular dynamics simulation and frictional force microscopy experiments for the precise observation of slip motion between a graphene layer and a crystalline silicon tip.

Study for optical manipulation of a surfactant-covered droplet using lattice Boltzmann method.

In this study, we simulated deformation and surfactant distribution on the interface of a surfactant-covered droplet using optical tweezers as an external source. Two optical forces attracted a single droplet from the center to both sides. This resulted in an elliptical shape deformation.

Effect of hydrodynamic and fluid-solid interaction forces on the shape and stability of a droplet sedimenting on a horizontal wall.

In this paper, we study the sedimentation of droplet onto horizontal surfaces using a Shan and Chen multicomponent lattice Boltzmann model [Shan and Chen, Phys. Rev. E 47, 1815 (1993)].

Two-phase numerical model for thermal conductivity and convective heat transfer in nanofluids.

Due to the numerous applications of nanofluids, investigating and understanding of thermophysical properties of nanofluids has currently become one of the core issues. Although numerous theoretical and numerical models have been developed by previous researchers to understand the mechanism of enhanced heat transfer in nanofluids; to the best of our knowledge these models were limited to the study of either thermal conductivity or convective heat transfer of nanofluids. We have developed a numerical model which can estimate the enhancement in both the thermal conductivity and convective heat transfer in nanofluids.

Investigation of heat transfer in turbulent nanofluids using direct numerical simulations.

A numerical study has been performed by using a combined Euler and Lagrangian method on the convective heat transfer of Cu and Al2O3 nanofluids under the turbulent flow conditions. The effects of volume fraction of nanoparticles, nanoparticle sizes, and nanoparticle material are investigated. The mechanism of convective heat transfer enhancement in nanofluids has also been investigated, by studying the influence of particle dispersion and two-way interaction between fluid and particle temperature.