Conference Papers
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506
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Item Flow analysis for efficient design of wavy structured microchannel mixing devices(American Institute of Physics Inc. subs@aip.org, 2018) Kanchan, M.; Maniyeri, R.Microfluidics is a rapidly growing field of applied research which is strongly driven by demands of bio-technology and medical innovation. Lab-on-chip (LOC) is one such application which deals with integrating bio-laboratory on micro-channel based single fluidic chip. Since fluid flow in such devices is restricted to laminar regime, designing an efficient passive modulator to induce chaotic mixing for such diffusion based flow is a major challenge. In the present work two-dimensional numerical simulation of viscous incompressible flow is carried out using immersed boundary method (IBM) to obtain an efficient design for wavy structured micro-channel mixing devices. The continuity and Navier-Stokes equations governing the flow are solved by fractional step based finite volume method on a staggered Cartesian grid system. IBM uses Eulerian co-ordinates to describe fluid flow and Lagrangian co-ordinates to describe solid boundary. Dirac delta function is used to couple both these co-ordinate variables. A tether forcing term is used to impose the no-slip boundary condition on the wavy structure and fluid interface. Fluid flow analysis by varying Reynolds number is carried out for four wavy structure models and one straight line model. By analyzing fluid accumulation zones and flow velocities, it can be concluded that straight line structure performs better mixing for low Reynolds number and Model 2 for higher Reynolds number. Thus wavy structures can be incorporated in micro-channels to improve mixing efficiency. © 2018 Author(s).Item Numerical Study on the Behavior of an Elastic Capsule in Channel Flow Using Immersed Boundary Method(Springer Science and Business Media Deutschland GmbH, 2020) Maniyeri, R.; Kang, S.The study of motion and dynamic behavior of elastic capsules in Poiseuille flow in a channel has become an interesting topic of research because of the wide range of applications in the field of biomedical engineering. The behavior of an elastic capsule in an externally applied flow is challenging because of the large displacement fluid–elastic structure interaction involved. In this work, we develop a computational model to capture the physics of the motion and behavior of an elastic capsule in Poiseuille flow in a channel using an immersed boundary finite volume method. The circular-shaped capsule is divided into a number of immersed boundary (IB) points. We create elastic links structure between IB points to incorporate tension/compression and bending. The flow is governed by continuity and Navier–Stokes equations which are discretized using staggered grid-based finite volume method. Dirac delta function is used to interpolate between solid (capsule) and fluid grids. Simulations are first carried out to describe the instantaneous position and shape of the capsule at a fixed Reynolds number flow in the channel. It is observed that the initial location has a significant influence in determining the final shape and position of the capsule. Further, through numerical simulations, the position and shapes of circular capsule in center-line motion with different stiffness constants for links are obtained and compared. It is found that lower elastic spring constant together with lower bending stiffness constant leads to larger deformation of the capsule because of less resistance to the flow. Also, the outcome of different Reynolds numbers (Re) on the behavior of the capsule is investigated for the center-line motion. It is noticed that the motion of the capsule retards with the increase in Reynolds number. Also, for higher value of Re, the capsule deforms less. For lower value of Re, the capsule deforms to a large extent. © 2020, Springer Nature Singapore Pte Ltd.Item Mixing in Oscillating Lid Driven Cavity—A Numerical Study(Springer Science and Business Media Deutschland GmbH, 2021) Neeraj, M.P.; Maniyeri, R.The mixing problems are highly important to be dealt with in fluid mechanics. In the present work mixing in a lid driven cavity with constant top wall velocity and oscillating top wall velocity is addressed. The staggered grid system is used and discretization of continuity equation, Navier–Stokes equations and concentration equation are done using Finite Volume Method. The Euler Explicit scheme is used for solving the numerical problem. Firstly, the developed computational model is validated with that of other researcher’s results for the case of constant top wall motion. Then the simulation is done for oscillating top wall for a Reynolds number of 100 and two amplitudes. The results in both cases are compared. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Numerical Study of Double Wall Oscillating Lid Driven Cavity(Springer Science and Business Media Deutschland GmbH, 2023) Yaswanth, D.; Maniyeri, R.This paper presents a two-dimensional finite volume method-based computational model to understand the mixing phenomena in a double wall oscillating square lid driven cavity. The study is mainly performed to see the effect of Schmidt number by employing SIMPLE algorithm to solve the discretized equations of mass, momentum and concentration. The developed code in FORTRAN is validated by comparing with previous works. Numerical simulations are conducted on parallel and antiparallel wall oscillations and found that low Schmidt number provides better mixing in both cases. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.