Browsing by Subject "lattice Boltzmann method"

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    Computational Fluid Dynamics for Modeling and Simulation of Intraocular Drug Delivery and Wall Shear Stress in Pulsatile Flow
    (2020-08) Abootorabi, Seyedalireza; Yu, Huidan; Nematollahi, Khosrow; Yokota, Hiroki
    The thesis includes two application studies of computational fluid dynamics. The first is new and efficient drug delivery to the posterior part of the eye, a growing health necessity worldwide. Current treatment of eye diseases, such as age-related macular degeneration (AMD), relies on repeated intravitreal injections of drug-containing solutions. Such a drug delivery has significant cant drawbacks, including short drug life, vital medical service, and high medical costs. In this study, we explore a new approach of controlled drug delivery by introducing unique porous implants. Computational modeling contains physiological and anatomical traits. We simulate the IgG1 Fab drug delivery to the posterior eye to evaluate the effectiveness of the porous implants to control the drug delivery. The computational model was validated by established computation results from independent studies and experimental data. Overall, the results indicate that therapeutic drug levels in the posterior eye are sustained for eight weeks, similar to those performed with intravitreal injection of the same drug. We evaluate the effects of the porous implant on the time evaluation of the drug concentrations in the sclera, choroid, and retina layers of the eye. Subsequent simulations were carried out with varying porosity values of a porous episcleral implant. Our computational results reveal that the time evolution of drug concentration is distinctively correlated to drug source location and pore size. The response of this porous implant for controlled drug delivery applications was examined. A correlation between porosity and fluid properties for the porous implants was revealed in this study. The second application lays in the computational modeling of the oscillating
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    Interactive 3D simulation for fluid–structure interactions using dual coupled GPUs
    (Springer, 2018-01) Zigon, Bob; Zhu, Luoding; Song, Fengguang; Mathematical Sciences, School of Science
    The scope of this work involves the integration of high-speed parallel computation with interactive, 3D visualization of the lattice-Boltzmann-based immersed boundary method for fluid–structure interaction. An NVIDIA Tesla K40c is used for the computations, while an NVIDIA Quadro K5000 is used for 3D vector field visualization. The simulation can be paused at any time step so that the vector field can be explored. The density and placement of streamlines and glyphs are adjustable by the user, while panning and zooming is controlled by the mouse. The simulation can then be resumed. Unlike most scientific applications in computational fluid dynamics where visualization is performed after the computations, our software allows for real-time visualizations of the flow fields while the computations take place. To the best of our knowledge, such a tool on GPUs for FSI does not exist. Our software can facilitate debugging, enable observation of detailed local fields of flow and deformation while computing, and expedite identification of ‘correct’ parameter combinations in parametric studies for new phenomenon. Therefore, our software is expected to shorten the ‘time to solution’ process and expedite the scientific discoveries via scientific computing.
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    A three-dimensional immersed boundary method for non-Newtonian fluids
    (Elsevier, 2018-05) Zhu, Luoding; Mathematical Sciences, School of Science
    Fluid-structure-interaction (FSI) phenomenon is common in science and engineering. The fluid involved in an FSI problem may be non-Newtonian such as blood. A popular framework for FSI problems is Peskin's immersed boundary (IB) method. However, most of the IB formulations are based on Newtonian fluids. In this letter, we report an extension of the IB framework to FSI involving Oldroyd-B and FENE-P fluids in three dimensions using the lattice Boltzmann approach. The new method is tested on two FSI model problems. Numerical experiments show that the method is conditionally stable and convergent with the first order of accuracy.