Prasad Sonar - Publications

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Prasad Sonar, Hiroya Watanabe & Yoshiyuki Tagawa, "Impact-Induced Liquid Jet Formation with a Bubble-Encapsulated Gel".

In preparation.

We investigate impact-induced jet formation in a gel containing a trapped bubble, aiming to understand how the bubble influences jet velocity and surface vibrations. In our experiments, a tube is partially filled with PVA gel and water, with a bubble of known size trapped in the gel. Upon impact, the liquid interface reverses and forms a focused jet. Our results indicate that the bubble increases jet velocity, mimicking cavitation effects.

Prasad Sonar, Yuto Yokoyama, Kohei Yamagata, & Yoshiyuki Tagawa, "Stress analysis in human tissue simulants subjected to high-speed fluid jet penetration".

To be submitted.

We conducted systematic experiments to analyze stress patterns induced by high-speed fluid jets penetrating soft tissue simulants, using gelatin as a tissue simulant. Our findings showed that uniform fluid jets formed narrow channels with localized, low-intensity stresses, while gelatin produced successive stress waves upon jet penetration, with effects lasting over time. By comparing device performance, we gained insights into jet penetration mechanics, demonstrating the value of the photoelastic technique for measuring stresses in soft tissue interactions with high-speed jets.

Prasad Sonar, A. Bhateja, & I. Sharma, "Granular flows over normally vibrated inclined bases".

Accepted in Phys. Rev. Fluids. Arxiv.

We study granular flows on an inclined rigid base that is vibrated vertically using DE simulations. We find an appreciable change in the flow profiles when the base is vibrated, with an overall increase in the flow velocity and dilation across the depth. We characterize the mass flow rate, Q, in terms of a non-dimensional number S, which is the ratio of vibrational and gravitational energies.

Prasad Sonar & Hiroaki Katsuragi, "Air-jet impact craters on granular surfaces: a universal scaling". J. Fluid Mech., 2024.

Download pdf.

In studying rocket landing scenarios, we investigate crater morphology resulting from a turbulent air jet impinging on granular surfaces. The derived scaling reveals a crossover in the length scales that govern the crater's aspect ratio, offering valuable insights for ensuring safe landings.

Prasad Sonar & Hiroaki Katsuragi, "Fracturing-induced fluidization of vibrated fine-powder column", Powder Technology 421, 118405, 2023.

Download pdf. Arxiv.

We experimentally study how fine and cohesive group C powders can be effectively fluidized.

Powder Fluidization, Powder Technology, 2023

Prasad Sonar & Hiroaki Katsuragi, "Decompaction-wave propagation in a vibrated fine powder bed", Phys. Rev. E, 106(1), 014905, 2022.

Download pdf. Arxiv.

We experimentally study how cracks form and decompaction waves move through a vibrated powder bed made of 5 µm glass beads.

Prasad Sonar, S. Modi & I. Sharma, "Estimating forces during ploughing of a granular bed". J. Fluid Mech. 875, 376-410, 2019.

Download pdf. Arxiv.

We present a method to predict the forces on a plough, modeled as a flat, rigid plate angled in the direction of motion, as it moves through a granular bed. Our method combines simple discrete element (DE) simulations with continuum mechanics.

Prasad Sonar, I. Sharma, & Jayant K. Singh, "Granular flow down a flexible inclined plane", Powders & Grains-2017, Montpelier, France, July 2017.

Download pdf (Open access).

We study how granular flows behave on an inclined, flexible base. The base is modeled as a rigid platform on springs with one degree of freedom.

Email: prasadrsonar[at]gmail.com