Article
Mechanics
Rongzong Huang
Summary: We present a macroscopic dynamic van der Waals theory for liquid-vapor phase transition from mesoscopic perspectives offered by the kinetic model for multiphase fluids. The present dynamic equations are identical to the macroscopic equations recovered by the kinetic model, revealing the excess effects caused by unbalanced long-range molecular interaction in the inhomogeneous region.
Article
Mechanics
Zhenyu Ouyang, Jianzhong Lin
Summary: The hydrodynamic behavior of a two-dimensional elongated micro-swimmer in a bulk fluid was studied using numerical methods. The study found that the swimming speed and power expenditure of different types of swimmers varied depending on their structures and the flow conditions.
Article
Mechanics
Zhenyu Ouyang, Jianzhong Lin, Nhan Phan-Thien
Summary: An immersed boundary-lattice Boltzmann method is used to study the swimming behavior of a squirmer array in a Newtonian fluid. The results show that the array configuration and spacing have significant effects on the swimming speed, power expenditure, and hydrodynamic efficiency. It is also found that larger spacings tend to result in instability and higher energy efficiency can be achieved with smaller spacings.
Article
Mechanics
Qin Xu, Zijian Zhuang, Yongcai Pan, Binghai Wen
Summary: In this paper, a super-resolution transformer is proposed to reconstruct turbulent flow fields with high quality. Through experiments on forced isotropic turbulence and turbulent channel flow datasets, the results show that the proposed method can recover the turbulent flow fields with high spatial resolution and capture small-scale details. It can also handle both isotropic and anisotropic turbulent properties even in complex flow configurations.
Article
Mechanics
Guoqiang Wu, Sheng Chen
Summary: This study investigated the collision of a moving droplet against a moving particle under gravity, analyzing the impacts of Bond number, particle surface wettability, particle-droplet size ratio, and eccentricity ratio. Six key findings were reported, including observations of agglomeration process, influence of wettability on particle velocity, delay in deceleration with increased size ratio, differences in velocities with eccentricity ratio, critical value for maximum particle velocities, and the discovery of a rebound regime in vertical collisions. These findings provide insights into the collision mechanism and contribute to the existing literature on such interactions.
Article
Mechanics
Eslam Ezzatneshan, Reza Sadraei
Summary: This study investigates the effects of vibration on droplet dynamics inside a three-dimensional porous medium. The results show that contact angle significantly affects the volume and duration of droplet drainage. Hydrophilic pores hinder droplet drainage and resist vibration, while a hydrophobic surface leads to quicker drainage. The study also finds that increasing the vibration frequency can enhance droplet separation and improve drainage.
Article
Mechanics
Alessandro De Rosis, Alex Skillen
Summary: The flow physics generated by vortex-wall collision in an electrically conductive fluid is numerically investigated. The presence of a magnetic field is found to significantly modify the vortex dynamics, exerting a braking effect on the vortex that increases with the magnetic Prandtl number. The findings are linked to the energy transfer between the velocity and the magnetic fields as well as to the evolution of their enstrophies.
Article
Food Science & Technology
R. G. M. van der Sman
Summary: In this paper, a Lattice Boltzmann model using the enthalpy method is presented for food freezing. The freezing of par-fried french fries is used as a case study, and the simulations show that under industrial-relevant freezing conditions, the crust region remains either unfrozen or only partially frozen. This result is important for addressing the quality problem of crust fracturing during finish-frying.
CURRENT RESEARCH IN FOOD SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Jia Xu, TieZhu Qiao, Qing Li, GuoWei Zhang, GuiRong Hao
Summary: This study proposes an optimization method of crystal rotation to improve the quality of crystal seeding under complex convection. By calculating and analyzing the unsteady melt flow rate, internal temperature of the melt, and crystal rotation speed, the results show that this method can effectively restrain melt convection and improve the temperature distribution on the surface of the melt.
Article
Materials Science, Multidisciplinary
Yang Enjian, Chen Hongfei, Guo Guanshun, Song Yan, Zhang Lei
Summary: Inkjet-printed solar cell metallization is an important non-contact alternative, and the solidification of metallic silver on the silicon wafer directly affects the Ag/Si contact of printed finger electrode. In this study, a 3D LB model coupled with CA algorithms is established to analyze the dendritic growth during solidification. The model successfully reproduces the typical dendritic microstructures and shows that the textured features of the silicon wafer accelerate the growth of secondary and tertiary dendrites. The numerical analysis of dendritic growth can help optimize the inkjet-printed solar cell metallization process.
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
(2023)
Article
Physics, Fluids & Plasmas
Hong Liang, Runlong Wang, Yikun Wei, Jiangrong Xu
Summary: In this paper, an accurate interface-capturing lattice Boltzmann method is proposed based on the modified Allen-Cahn equation for modeling an immiscible multiphase flow system. The proposed method is built on the relation between the signed-distance function and the order parameter, maintaining the mass-conserved characteristic. By carefully incorporating a suitable forcing term, the target equation can be correctly recovered. Simulation results for various interface-tracking problems demonstrate that the proposed model is more numerically accurate, particularly at a small interface-thickness scale, compared to existing lattice Boltzmann models for the conservative Allen-Cahn equation.
Article
Mechanics
Kaimin Wang, Han Chen, Hongyu Ge, Xiaohua Liu, Hongsheng Liu, Shengqiang shen
Summary: This paper numerically investigates the impact of successive double droplets on a super-hydrophobic tube surface using a three-dimensional model. The impact velocity and curvature ratio significantly affect the impact behavior, with different impact models observed under varying conditions. The study also discusses in detail the breakup of liquid films and the occurrence of air entrainment, providing insights into the mechanisms behind these phenomena.
Article
Mechanics
Shang-Gui Cai, Sajad Mozaffari, Jerome Jacob, Pierre Sagaut
Summary: This paper applies an immersed boundary-turbulence wall modeling approach to investigate turbulent flows over a generic car geometry, known as the Ahmed body. The study shows that the near-wall solution is significantly deteriorated compared to the body-fitted simulation, but enhanced wall treatments proposed in the literature can effectively address this issue.
Article
Mechanics
Yunjie Xu, Linlin Tian, Chunling Zhu, Ning Zhao
Summary: This study investigates the impact dynamics and contact time of droplets on superhydrophobic surfaces with protrusions using a three-dimensional simulation method. The results show that the bouncing type and retraction way significantly affect the contact time, depending on combinations of Weber number, protrusion size, and shape.
Article
Mechanics
Yi Zhou, Zhengdao Wang, Yuehong Qian, Hui Yang, Yikun Wei
Summary: This study presents a numerical investigation on flow around two square cylinders in different arrangements, revealing various flow patterns that can be categorized into three types depending on the spacing between the cylinders. The dependence of flow parameters on spacing is demonstrated, and the relationship between flow pattern and lift and drag coefficients is explored.
Article
Physics, Multidisciplinary
Nicolo Frapolli, Shyam Chikatamarla, Ilya Karlin
Article
Mechanics
M. H. Saadat, I. V. Karlin
Article
Mechanics
N. Sawant, B. Dorschner, I. V. Karlin
Summary: A new lattice Boltzmann model for multicomponent ideal gas mixtures is proposed, which consists of two parts for modeling the dynamics and energy of the mixture. The model eliminates passive scalar advection-diffusion coupling and extends the lattice Boltzmann equation to the compressible flow regime on the standard three-dimensional lattice.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Physics, Multidisciplinary
Mohammad Hossein Saadat, Benedikt Dorschner, Ilya Karlin
Summary: The translation describes a method of modifying conventional lattice Boltzmann models to remain effective at higher flow velocities and temperatures, and validates this approach through simulations of benchmark problems in two and three dimensions.
Article
Mechanics
M. H. Saadat, S. A. Hosseini, B. Dorschner, I. V. Karlin
Summary: The two-population lattice Boltzmann model proposed in this study accurately simulates compressible flows, demonstrating good performance even in the presence of turbulence and shock waves.
Article
Multidisciplinary Sciences
N. Sawant, B. Dorschner, I. Karlin
Summary: A new lattice Boltzmann model for reactive ideal gas mixtures is proposed, which improves the kinetic model for Stefan-Maxwell diffusion and enhances thermodynamic consistency by incorporating the heat of formation to accurately describe the energy and temperature changes due to chemical reactions. The model is validated with benchmarks including laminar burning speed in hydrogen-air mixture and circular expanding premixed flame, demonstrating its effectiveness for reactive flows.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2021)
Article
Mechanics
Abhimanyu Bhadauria, Benedikt Dorschner, Ilya Karlin
Summary: This paper introduces a two-way coupled fluid-structure interaction scheme for rigid bodies using a two-population lattice Boltzmann formulation for compressible flows. The model, validated with several test cases, accurately captures dynamic behavior of systems, especially in the compressible flow regime. It demonstrates the ability to accurately describe complex phenomena, such as transonic flutter over an airfoil.
Article
Mechanics
N. Sawant, B. Dorschner, I. Karlin
Summary: A new lattice Boltzmann model (LBM) is proposed for chemically reactive mixtures, which extends the non-reactive LBM to include diffusion and flow modeling for chemical species and compressible flow. The model is validated against direct numerical simulation and shows excellent accuracy and applicability for complex reactive flows.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
S. A. Hosseini, B. Dorschner, I. V. Karlin
Summary: This paper revisits the construction of discrete kinetic models for single-component isothermal two-phase flows. The authors show the correspondence between the kinetic model for a non-ideal fluid and the Navier-Stokes equations with a non-ideal equation of state. They also introduce a scaling based on velocity increments to recover the full Navier-Stokes-Korteweg equations. The proposed model is validated on various benchmarks and exhibits thermodynamic and hydrodynamic consistency.
JOURNAL OF FLUID MECHANICS
(2022)
Review
Computer Science, Interdisciplinary Applications
S. A. Hosseini, M. Atif, S. Ansumali, I. V. Karlin
Summary: In the late 90's and early 2000's, the concept of using a discrete H theorem and Lyapunov functionals as a way to ensure stability of lattice Boltzmann solvers brought about a paradigm shift in their construction and opened up new discussions and perspectives. The entropic construction, which introduced a discrete entropy functional and enforced an H-theorem, proved to be effective in stabilizing lattice Boltzmann solvers in various applications including weakly compressible, fully compressible, and multi-phase flows. In this review, we discuss the basic building blocks of the entropic lattice Boltzmann method and its extension to multiphase and compressible flows.
COMPUTERS & FLUIDS
(2023)
Article
Computer Science, Interdisciplinary Applications
Ehsan Reyhanian, Benedikt Dorschner, Ilya Karlin
Summary: In this exploratory study, shock-capturing schemes are applied to simulate compressible flows with shock waves and discontinuities. The model is based on the semi-Lagrangian method and employs concepts like total variation diminishing and weighted essentially non-oscillatory schemes to capture the discontinuities and shock waves. The results show that the reconstruction schemes effectively remove oscillations at the shock wave location, allowing for stable simulations of compressible benchmarks. The numerical properties of the reconstruction schemes, such as spectral analysis and order of accuracy, are also discussed.
COMPUTERS & FLUIDS
(2023)
Article
Physics, Fluids & Plasmas
N. G. Kallikounis, B. Dorschner, I. V. Karlin
Summary: The study utilizes the particles-on-demand method to simulate compressible flows with strong discontinuities in density, pressure, and velocity. The method is modified through regularization by Grad's projection and reference frame transformations, as well as the implementation of a finite-volume scheme to improve stability, accuracy, and conservation of mass, momentum, and energy. The proposed model demonstrates excellent performance in various benchmarks, surpassing the limitations of other lattice Boltzmann-like approaches to compressible flows.
Article
Physics, Fluids & Plasmas
N. G. Kallikounis, B. Dorschner, I. Karlin
Summary: A multi-scale lattice Boltzmann scheme is proposed to adaptively refine particles' velocity space, efficiently coupling different velocity sets of lower and higher order. The scheme shows flexibility in model selection and reduction in computational requirements, validated in various flow setups.
Article
Mathematics, Interdisciplinary Applications
Ehsan Reyhanian, Benedikt Dorschner, Ilya Karlin
Summary: The study presents a kinetic model for compressible non-ideal fluids that imposes local thermodynamic pressure through rescaling particle velocities for full thermodynamic consistency. The model, which is Galilean invariant, treats mass, momentum, and energy as local conservation laws. Benchmark simulations demonstrate accurate and robust performance across different scenarios, showing excellent agreement with theoretical analysis and experimental correlations. The model is capable of operating in the entire phase diagram, including super- and sub-critical regimes, and inherently captures phase-change phenomena.
Article
Physics, Fluids & Plasmas
M. H. Saadat, F. Boesch, I. Karlin
