Faculty Publications
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Item Inertial Migration of Cylindrical Particle in Stepped Channel—A Numerical Study(Springer Science and Business Media Deutschland GmbH, 2022) Neeraj, M.P.; Maniyeri, R.; Kang, S.Inertial migration of solid rigid particle in fluid flow occurs by the virtue of pure mechanical forces and it can play a pivotal role in separation techniques. The present computational study tries to capture the inertial migration dynamics of single rigid neutrally buoyant cylindrical particle in fluid flow which is residing in a stepped (sudden contraction) channel by determining the equilibrium position and migration time. The immersed boundary method based on feedback forcing scheme is used to develop the numerical model. The particle performs both translation and rotation motion according to the fluid flow condition and is modelled as rigid immersed boundary and the governing fluid momentum, and continuity equations are discretized using finite volume method in a staggered grid system and solved using semi-implicit fractional step algorithm. The study is mainly performed for centre and off-centre initial positions and its influence on the equilibrium position and migration time. It is observed that the equilibrium position is dependent on the initial position of release of particle. As initial position shifts from centre of channel, the particle equilibrium position also shifts accordingly. Further, the effect of height and length of step (contraction portion) on lateral migration is explored. The equilibrium position is found to be shifting towards the upper wall with decrease in height of step. However, the change in height of step does not have any significant effect on migration time of particle. It is identified that the increase in length of step reduces the migration time of particle although the equilibrium position remains same. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Numerical Simulation of Inertial Migration of Elliptical Particle Using Immersed Boundary Method(Springer Science and Business Media Deutschland GmbH, 2023) Neeraj, M.P.; Maniyeri, R.The particles suspended in a flowing fluid migrates with respect to the lift forces experienced which is generated by the virtue of the fluid. This type of movement which occurs without the aid of any external forces is known as inertial migration. The present work tries to construct a two-dimensional computational model to analyse the lateral migration of a neutrally buoyant rigid elliptical particle in Poiseuille flow which takes place in straight channel. The feedback forcing based immersed boundary methodology is adopted to build the numerical model. The inertial migration is addressed by studying the characteristics of equilibrium position and migration time. The effect of aspect ratio and initial release configuration of elliptical particle on the equilibrium position and migration time is observed with the use of the simulation results. The equilibrium is observed to be close to 0.6 times half the half of height of channel or more specifically at 0.27 for an aspect ratio of 3.333. However, with reduction in aspect ratio to 1.5 the equilibrium position shifts closer to 0.26. The decrease in aspect ratio from 3.333 to 1.5 also produces reduction in migration time from 5.906 to 4.074. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Lateral Migration of Three Particles Through a Slit—An Immersed Boundary Computational Analysis(Springer Science and Business Media Deutschland GmbH, 2024) Neeraj, M.P.; Maniyeri, R.The current work focuses on the migration of three particles in Poiseuille flow through a slit microchannel. The immersed boundary finite volume methodology based on feedback forcing scheme is used to build the computational model for the analysis of particle migration through slit. Three rigid non-neutrally buoyant cylindrical particles are released from same lateral position in a channel of 20 × 1 dimension. It is observed that the particles travel through the slit and attain equilibrium position at the center of the channel. Further, the influence of slit gap and angle on the equilibrium position and residence time is studied. It is interesting to see that the equilibrium position stays unaffected by the changes in both of the above mentioned parameters. However, the residence time increases with the slit gap. It should be also noted that the migration time is the lowest for a slit angle of Ï€/2. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Control force and inertial migration in Poiseuille flow: a computational study(Taylor and Francis Ltd., 2023) Neeraj, M.P.; Maniyeri, R.The present work deals with the development of a numerical model to analyze the effect of control force on a single rigid massive cylindrical particle’s lateral migration in a straight channel. The finite volume immersed boundary method (feedback forcing-based), along with semi-implicit strategy, is incorporated to create a computational model. The control force is applied in the direction against the fluid flow, to control the equilibrium position and drive it to the channel center. The effect of the Reynolds number, particle diameter and density ratio on the control force is studied. From parametric studies, a prediction model is developed for the control force with the Reynolds number, particle diameter and density ratio as inputs. The linear regression methodology in machine learning is utilized to create the prediction model. The predicted values of control force are observed to match those of the simulation results. © 2023 Taylor & Francis Group, LLC.Item Lateral migration of cylindrical particle in a constricted microchannel—A numerical study(John Wiley and Sons Inc, 2023) Neeraj, M.P.; Maniyeri, R.Inertial migration of a single cylindrical particle in a constricted microchannel is addressed in this work. A computational model (two-dimensional) has been constructed with the assistance of the immersed boundary finite volume method. The feedback forcing strategy is utilized for the simulation of lateral migration. The parameters like equilibrium position, migration time, and shortest equilibrium distance are computed to analyze the inertial migration characteristics of the particle. Also, a comprehensive parametric study has been performed on the migration behaviour of particles inside the constricted channel by addressing the effects of Reynolds number, diameter, initial release position, and constriction clearance. The parametric study shows that the equilibrium position changes with variations in the initial release position and particle diameter. On the other hand, it stays unaffected by changes in Reynolds number and constriction clearance. The parameters like the shortest equilibrium distance and migration time increase with a rise in Reynolds number and particle diameter. On the other hand, it reduces with the reduction in constriction clearance. Inspired by the parametric study results, in the following stage, a prediction model is created with an artificial neural network algorithm. This is used for an effective forecast of equilibrium position, migration time, and shortest equilibrium distance. Further, the computational model is utilized to check for the existence of a critical Reynolds number for the particle movement in a constricted microchannel. It is observed that the critical Reynolds number remains unchanged with a change in particle diameter. However, it increases linearly with an increase in constriction clearance. © 2022 Canadian Society for Chemical Engineering.Item Inertial migration and control force in pulsatile flow- a computational study(Taylor and Francis Ltd., 2024) Neeraj, M.P.; Maniyeri, R.The current work proposes a numerical model for analysing the inertial migration of cylindrical-shaped rigid particles in pulsatile flow. The particle is non-neutrally buoyant, and the numerical model is built using a feedback forcing-based immersed boundary scheme. For shifting particle equilibrium position towards the channel centre, an opposing flow control force is applied. The relationship between control force and parameters such as particle diameter, Reynolds number, and density ratio is thoroughly investigated and reported here. The magnitude of the control force increases with Reynolds number and decreases with particle diameter. With density ratio, on the other hand, the magnitude of the control force first drops and then rises. Based on the results of the parametric study a prediction model for the control force is developed with the help of a linear regression algorithm. © 2024 Indian Institute of Chemical Engineers.