Pitambar Randive

Mesoscopic Modeling of Capillarity-Induced Two-Phase Transport in a Microfluidic Porous Structure

Mesoscopic modeling at the pore scale offers great promise in exploring the underlying structure transport performance of flow through porous media. The present work studies the fluid flow subjected to capillarity-induced resonance in porous media characterized by different porous structure and wettability. The effects of porosity and wettability on the displacement behavior of the fluid flow through porous media are discussed. The results are presented in the form of temporal evolution of percentage saturation and displacement of the fluid front through porous media. The present study reveals that the vibration in the form of acoustic excitation could be significant in the mobilization of fluid through the porous media. The dependence of displacement of the fluid on physicochemical parameters like wettability of the surface, frequency along with the porosity is analyzed. It was observed that the mean displacement of the fluid is more in the case of invading fluid with wetting phase where the driving force strength is not so dominant.

Lattice Boltzmann Modelling of Capillarity-Induced Resonance of Blob Inside a Circular Tube

The capillarity induced resonance has been one of the promising method as far as the mobilization of trapped blob is concerned. In this context, lattice Boltzmann Shan and Chen model is employed to analyze the movement of a 3-D immiscible blob influenced by oscillatory acoustic excitation in a tube. The influence of the physicochemical parameters which includes wettability, width of tube, viscosity, magnitude of the force and frequency on blob dynamics are discussed. The effect of frequency on the blob shows peak displacement of the blob at resonance frequency. The resonance behaviour of blob with various wettabilities and capillary numbers is analyzed to understand capillarity-wettability interaction. Mobilization study of the blob reveals that wettability plays a crucial role in the blob mobilization at low capillary number.

Lattice Boltzmann simulations of coalescence of two droplets on a rectangular channel wall considering wetting effects

The present work numerically analyses the interfacial dynamics of coalescence of two droplets on a rectangular channel wall considering wetting effects. The two-phase lattice Boltzmann Shan-Chen model has been incorporated to explore the physics of coalescence of two droplets on channel wall. The main focus of the study is to analyse the time taken by the two droplets to initiate merging into a single droplet and the displacement of immiscible droplets subjected to gravitational forces. The impact of the centre distance between the two droplets (i.e., Cd = 47-55 lu) and capillary number (i.e., Ca = 0.35, 0.50 and 0.81) on droplet dynamics have been examined. The investigation revealed that the two droplets do not merge completely into a single spherical droplet in mixed wettability case but stretched at the junction of hydrophilic and hydrophobic region. It is further revealed that the two droplets coalesce faster on mixed wettable surface compared to uniform hydrophilic surface at a fixed capillary number.

Simulation of Blob Dynamics Inside a Channel Under Acoustic Excitation

The displacement of a three-dimensional immiscible blob subject to oscillatory acoustic excitation in a channel is studied with the Lattice Boltzmann method. The effects of amplitude of the force, viscosity and frequency on blob dynamics are investigated. The trend for variation of mean displacement of blob and frequency response is in agreement to that of the previous two-dimensional studies reported in literature. The response of the blob with pinned contact line shows underdamped behavior. It is also found that increasing the amplitude of the force increases the mean displacement and frequency response.Copyright