Bulletin of the American Physical Society
71st Annual Meeting of the APS Division of Fluid Dynamics
Volume 63, Number 13
Sunday–Tuesday, November 18–20, 2018; Atlanta, Georgia
Session E32: Lattice Boltzmann and Smoothed Particle Hydrodynamics Methods |
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Chair: Ulf Schiller, Clemson University Room: Georgia World Congress Center B404 |
Sunday, November 18, 2018 5:10PM - 5:23PM |
E32.00001: Smoothed Particle Hydrodynamics Method for Multi-physics Fluid Flows Manuel Hopp-Hirschler, Omar K Matar, Mostafa Safdari Shadloo Smoothed Particle Hydrodynamics (SPH) is a relatively new meshless numerical approach which has attracted significant attention in the last two decades. Compared with the conventional mesh-based computational fluid dynamics (CFD) methods, SPH exhibits some unique advantages in modelling multiphysics fluid flows and associated transport phenomena due to its capabilities of handling complex boundary evolution as well as modelling complicated physics in a relatively simple manner. On the other hand, as SPH is still a developing CFD method, it is crucial to identify its advantages and limitations in modelling realistic multiphysics flow problems of real life. Toward this end, this works aims at developing an Incompressible SPH (ISPH) model for multiphase multiphysics fluid flow problems. The presented model is based on the continuum surface force (CSF) approach including Marangoni force as well as leaky dielectric assumption including the Lorentz force for treating thermo-capillary and electrohydrodynamics (EHD) flows, respectively. We carefully validate the proposed model using several test cases that confirms its applicability and accuracy for such Multiphysics problems. |
Sunday, November 18, 2018 5:23PM - 5:36PM |
E32.00002: Stabilization of liquid sloshing in the presence of foam using Lattice Boltzmann Modelling approach Zach Zajo, T Renganathan, S Pushpavanam The free surface of a glass of water which is moved periodically exhibits oscillatory motion with a high amplitude. The amplitude decreases significantly when a layer of foam is present on top. In this work we first experimentally study the effect of frequency and amplitude of motion on the deformation of the interface. We use a Lattice Boltzmann approach to describe the dynamics of the interface. The model based on a bottom up approach, i.e. Shan- Chen model is used to investigate the interface deformation. The role of the rheology of foam on the interface dynamics is studied using a diffuse interface model. The role of different rheological models of foam on the interface movement will be highlighted. Keywords: liquid sloshing, Lattice Boltzmann Method |
Sunday, November 18, 2018 5:36PM - 5:49PM |
E32.00003: Lattice Boltzmann Simulations of Drug Delivery in Stented Brain Arteries Ulf Schiller, Mehrdad Yousefi Cerebrovascular diseases such as brain aneurysms are a primary cause of adult disability and mortality. A possible treatment of aneurysms is the implantation of flow-diverting stents to stabilize the affected vessel. However, angioplasty procedures have adverse effects including in-stent restenosis. This risk can be reduced by using drug-coated stents that interrupt restenosis through local drug delivery, and knowledge of the spatio-temporal drug concentration in the blood vessel is a critical factor in improving stent design. The lattice Boltzmann method has been successfully applied to simulate blood flow in patient-specific models of brain arteries that are reconstructed from three-dimensional angiography images of the vasculature. In this contribution, we present an extension of this framework that uses virtual angioplasty to insert a drug-eluting stent into the segmented blood vessel. A lattice Boltzmann solver for the advection-diffusion equation is coupled to the fluid flow in order to study the diffusion of drug in the blood stream. We present results on the spatio-temporal distribution of drugs for different diffusion coefficients, stent-geometries, and coating patterns that can be used to optimize the design of vascular stents. |
Sunday, November 18, 2018 5:49PM - 6:02PM |
E32.00004: Analysis of particle focusing in a stratified flow using Lattice Boltzmann Simulations Kiran S Jyothi, T. Renganathan, S. Pushpavanam We develop a model which captures the dynamics of a particle, traversing streamlines in a stratified flow using the Lattice Boltzmann Method (LBM). The different hydrodynamic forces acting on the particle, cause it to undergo a cross-stream motion. The introduction of stratified co-flow of two liquids with different viscosities alters the gradient of the velocity profile as compared to a single phase flow. This change affects the shear gradient induced lift force acting on the particle, which enables us to manipulate its final equilibrium position. We analyse how different parameters like viscosity ratio, particle size, particle diameter to channel width ratio and the Reynolds number can affect the final equilibrium position of the particle. Differently sized particles can be made to attain distinct equilibrium positions by tuning these flow parameters. The analysis can be used to develop an efficient particle/cell separator or a microfluidic solution exchanger which has applications in the bio-medical field. Keyword: Lattice Boltzmann Method, Particle focusing, Stratified flow |
Sunday, November 18, 2018 6:02PM - 6:15PM |
E32.00005: Simulations on Ostwald Ripening by Using Lattice Boltzmann Methods Xiao-Peng Chen Lattice Boltzmann methods have solid basis of particle kinetics, and it can be extended to simulations for multiphase flows by simply adding inter-particle forces. It is proven that it shares common fundamentals with thermodynamic models, saying phase field model. Growth of bubbles is simulated by Shan-Chen multiphase lattice Boltzmann methods (SC-LBM). The tests for single and dual bubble growth show SC-LBM simulation agrees with Rayleigh-Plesset predictions, which is applied widely for cavitating phenomena. Further tests for a cluster of bubbles show that such processes fulfill reaction-limited phase separation (coarsening), one of the important regimes of Ostwald ripening. During the processes, a thermal equilibrium is reached, while the interfacial energy keeps decreasing. The phenomenon of larger bubble eating smaller bubble can be well captured. The results also show that the R ̅∼t^(1/2) and N∼t^(-1) scalings are well satisfied, where R ̅, N and t are the averaged bubble size, bubble number and time, respectively. We believe SC-LBM has great potential to be applied in both mechanical and chemical circumstances. |
Sunday, November 18, 2018 6:15PM - 6:28PM |
E32.00006: Weakly Compressible SPH for Interfacial Flow Mingyu Zhang Interface is a key issue in the study of multiphase flows existing in our daily life and industrial applications. Many mesh methods have been developed to treat the interface, including Level set method (LSM), volume of fluid (VOF), front tracking method (FT), and phase field method, et al. As a meshfree method, Smoothed Particle Hydrodynamics (SPH) can easily handle complex flows with interface. Weakly compressible SPH (WCSPH) for interfacial flow are developed in this research. The developed method has higher accuracy, efficiency and stability. In the WCSPH for free surface flow, surface particle is located and interface is reconstructed. In the WCSPH for multiphase flow, level set method is used to describe the interface and ghost fluid method is used to handle the jump condition at the interface. Numerical tests are implemented for drop-film interaction in 2D and 3D, parasitic currents in static drop, oscillation of elliptic drop and square drop. The developed WCSPH for interfacial flow are proved to be an useful tool for complex flows with interface. In the future, the developed WCSPH for interfacial flow will be applied to investigate the complex flows. And the compressible version will be developed. |
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