arXiv subjects

Kishorkumar Sarva

Publications and source records attributed to Kishorkumar Sarva.

3 recordsLinked to original sources

arXiv2026

Role of particle volume fraction on particulate suspension droplet evolution, transition and Hysteresis

We study the transitional dynamics of the non-Brownian particulate Newtonian liquid jet for different particle volume fractions ($\phi$). We focus on the influence of particle volume fraction on the critical inflow velocity at which the dripping-jetting (i.e., dripping to jetting and jetting to dripping) transition occurs for the ratio of the nozzle diameter to the particle diameter ($D_n/D_p$=20). The experiments were conducted by increasing (forward sweep) and decreasing (reverse sweep) the flow rate. These experiments were repeated for different volume fractions. We observe, with an increase in particle volume fraction, the transition from the dripping to the jetting regime occurs through a chaotic dripping regime. With an increase in the particle volume fraction, the jetting regime has occurred at early flow rates during dripping to jetting transition (in forward sweep), and the jetting to dripping transition (reverse sweep) occurred at a lower flow rate than the forward sweep. The particle volume fraction impacts the hysteresis observed for the Newtonian fluid. Due to the changes in the critical flow rate where transition occur, the widening of the hysteresis loop of flow rate with the pinchoff length is observed. The transition from dripping to jetting is observed to have the recurrent escape of the pinchoff mechanism as the jet length changes, influencing the droplet size distribution. The frequency of droplet pinchoff and droplet size have decreased as the particle volume fraction has increased. As the particle volume fraction increases, the size distribution between the dripping and jetting regimes decreases.

physics.flu-dyn↗

arXiv2025

Role of Transient Dynamics in Dripping-Jetting Transition in Newtonian Fluids

Dripping dynamics has been well studied over the past century and forms a classic example of chaotic system in physics. With an increase in the inlet flow rate, periodic droplet formation from a faucet becomes chaotic in terms of the droplet size and the length of the liquid column at the time of pinch-off. With a further increase in the flow rate, dripping regime transitions into jetting regime where the liquid column length is much longer than that observed in the dripping case. In general, dripping faucet is seen as a long time behavior of the system at fixed control parameters. In the steady state condition, different nonlinear behaviors such as periodic and chaotic formation of droplets are observed in the dripping and jetting regimes. It is known that dripping faucet shows chaotic dripping regime before jetting regime ensues. At a critical inlet velocity, $U_{m-d_j}$, we note that dripping to jetting transition occurs after several droplets have formed in the dripping regime. The transition behaviour can be characterized by the time evolution of the liquid jet length $L$ and droplet size $D_p$. Solution to slender jet equation show that the dripping-jetting transition region is a function of the fluid properties. Further, we show that perturbations in the inlet velocity can significantly modify the transient behavior of the dripping to jetting regime transition.

physics.flu-dyn↗

arXiv2023

Dynamics of a film flowing down a granular chain

We investigate the effects of fibre morphologies, such as single and granular chain with torus bead on liquid film evolution using experimental and axi-symmetric numerical simulations with a one-fluid formulation. We introduce a non-dimensional parameter 'Bead Ratio'($BR$), that is, the ratio of bead diameter to the film height. When both the $BR$ and its distance from the nozzle exceed critical values, selection mechanism leading to development of 'dominating' waves: from regularly spaced droplets to coarsening or droplet merging. The two mechanisms, influenced by the $BR$ for a single bead, contribute to droplet merging: the formation of the downstream healing length, which precipitates the initial stage, and it's oscillating behaviour resulting in droplet merging. When the bead position is away from the healing length far from the nozzle, the transient simulations capture behavior similar to the finite amplitude perturbations at the inlet. However, when the bead is within the healing length, the film evolution has only coarsening effect on the droplet spacing. When the bead spacing on a granular chain is less than the droplet spacing of a Rayleigh-Plateau regime is significantly altered.

physics.flu-dyn↗