Article
Engineering, Multidisciplinary
Hassnia Hajji, Lioua Kolsi, Kaouther Ghachem, Chemseddine Maatki, Ahmed Kadhim Hussein, Mohamed Naceur Borjini
Summary: This study presents two and three-dimensional numerical simulations of flow through sudden expansion and contraction microchannels. Results show the appearance of a separate vortex in the corner after sudden expansion for low Reynolds numbers, with the vortex separation length increasing for high Reynolds numbers. The three-dimensional character of flow is more pronounced for higher Reynolds numbers.
ALEXANDRIA ENGINEERING JOURNAL
(2021)
Article
Thermodynamics
Hassnia Hajji, Lioua Kolsi, Faouzi Askri, Chemseddine Maatki, Walid Hassen, Mohamed Borjini
Summary: The study shows that obstacles have a significant impact on fluid dynamics and heat transfer, especially leading to the formation of a separate vortex after the sudden expansion of the micro-channel.
Article
Engineering, Multidisciplinary
Mansoor Jadidi, Michael J. Simmonds, Abdolrahman Dadvand, Geoff Tansley
Summary: The relaxation time is crucial for the accuracy of simulation in the lattice Boltzmann method (LBM). However, there is limited research on evaluating the optimal relaxation time. This paper proposes a systematic approach to determine the optimal relaxation time, specifically for low Reynolds (Re) number flows resembling blood flow in micro-vessels. The LBM with D2Q9 lattice model is used to simulate Poiseuille flow in a micro-channel and its accuracy is compared to the analytical solution. It is found that the analytically predicted optimal relaxation time differs from the numerical solution, suggesting the need for correction when using analytical relaxation time in LBM code.
ALEXANDRIA ENGINEERING JOURNAL
(2022)
Article
Engineering, Aerospace
Damiano Casalino, Edoardo Grande, Gianluca Romani, Daniele Ragni, Francesco Avallone
Summary: Experimental and numerical results of a low Reynolds number propeller are presented as a preliminary step towards defining a benchmark configuration for low Reynolds number propeller aeroacoustics. The study identifies the experimental and numerical challenges of the benchmark and the relevance of fundamental research questions related to transition and other low Reynolds number effects.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Thermodynamics
Rasul Mohebbi, Yuan Ma
Summary: This research investigates the flow and heat transfer characteristics past three hot obstacles in a sudden expansion and contraction channel. The use of MWCNT-Fe3O4 Water hybrid nanofluid is employed to enhance heat transfer. The study explores the effects of Reynolds number, nanoparticle volume fraction, and different arrangements of discrete heat sources on flow pattern, temperature distribution, and heat transfer. Simulation is conducted using the lattice Boltzmann method.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Astronomy & Astrophysics
Julian Bernhardt, Christian S. Fischer, Philipp Isserstedt
Summary: We investigate the volume dependence of baryon number fluctuations near the critical endpoint of QCD by solving the nonperturbative quark propagator equations. Our results show that the fluctuations are significantly affected by the volume at small and intermediate finite cubic volumes, while their ratios remain practically unchanged.
Article
Engineering, Multidisciplinary
As'ad Alizadeh, Azher M. Abed, Hussein Zekri, Ghassan Fadhil Smaisim, Bahram Jalili, Pooya Pasha, Davood Domiri Ganji
Summary: This investigation focuses on the heat removal from surfaces with high heat flux, utilizing tabulators and parts with a unique geometry as a solution. The primary hypothesis is to enhance fluid heat transfer through increased turbulence and heat transfer area, achieved by the simultaneous use of a turbulator and increased contact surface. The research applies the limited volume method and Ansys Fluent software to solve governing equations and compares turbulators SLT and TRT with others in terms of Nusselt number and friction coefficient reduction.
ALEXANDRIA ENGINEERING JOURNAL
(2023)
Article
Engineering, Multidisciplinary
Bilal Ahmed, Asma Ashraf, Fizza Anwar
Summary: This paper numerically investigates the analysis of non-Newtonian Casson fluid induced by peristaltic activity, considering free from long wavelength and creeping flow regime. Rheological measurements are exposed by fluid progression in an asymmetric conduit influenced by a settled magnetic field. The study uses Galerkin finite element method to simplify the Navier-Stokes equations and includes the role of inertial forces in the flow model. The results show that increasing the Casson fluid parameter leads to a slight reduction in velocity near the central region and has no effect on the vorticity lines.
ALEXANDRIA ENGINEERING JOURNAL
(2023)
Article
Astronomy & Astrophysics
Julian Bernhardt, Christian S. Fischer, Philipp Isserstedt, Bernd-Jochen Schaefer
Summary: This study investigates the impact of finite volume and the corresponding restrictions on long-range correlations on the location of the critical endpoint in the QCD phase diagram. Utilizing a combination of lattice Yang-Mills theory and truncated versions of Dyson-Schwingcr equations, the researchers found that the critical endpoint's location is dependent on volume and boundary conditions. Notable volume effects are observed for volumes less than or equal to 5 fm, with larger volumes approaching the infinite-volume limit.
Article
Physics, Multidisciplinary
Kai Zhang, Xiu-Fang Feng, He-Fang Jing, Yao-Lin Jiang
Summary: The single relaxation time (SRT) lattice Boltzmann method (LBM) can cause non-physical oscillations when used to simulate flows with high Reynolds number. To solve this problem, a two dimensional (2D) model with nine discrete velocities and multiple relaxation time (MRT) lattice Boltzmann method is combined with an inertial-range (IR) model to establish a new model, named as D2Q9 MRT-IR model. The D2Q9 MRT-IR model is then used to simulate the flow in 2D lid-driven cavities, analyze the influence of Reynolds numbers on vortex core position, calculate the first transition Reynolds number (Rec1 = 7079), and investigate the periodic changes of the turbulent flow field in the cavity at three high Reynolds numbers. The simulated results show that the D2Q9 MRT-IR model can effectively simulate flows with high Reynolds number, and it is observed that the vortex center gradually moves to the geometric center of the cavity with the increase of the Reynolds number. Moreover, it is also observed that the flow transitions from laminar to turbulent when the Reynolds number reaches 7079. Additionally, it is also observed that the flow velocity at certain points changes periodically when the Reynolds number reaches its critical value, and the period decreases with the increase of the Reynolds number.
CHINESE JOURNAL OF PHYSICS
(2023)
Article
Thermodynamics
Likhan Das, Fazlay Rubbi, Khairul Habib, R. Saidur, Nazrul Islam, Bidyut Baran Saha, Navid Aslfattahi, Kashif Irshad
Summary: A new class of surfactant-free Ionanofluid was developed and its thermophysical and rheological properties were assessed, showing that the 0.10% Ionanofluid had the highest thermal conductivity enhancement. The study also investigated the hydrothermal performance of an insert-fitted DPHEX, with the rectangular-cut TT insert demonstrating the highest heat transfer enhancement.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Mohamed Ibrahim N.H., M. Udayakumar, Sivan Suresh, Suvanjan Bhattacharyya, Mohsen Sharifpur
Summary: This study investigates the insights of soot formation in ethylene/hydrogen/nitrogen diffusion jet flame, including soot volume fraction as a function of flame-normalized length and various soot formation rates. The originality of this study lies in coupling LES turbulent model with chemical equilibrium diffusion combustion and conducting SVF and its insights study for different Reynolds number configurations.
INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW
(2021)
Article
Mechanics
Aditi Sengupta, Prasannabalaji Sundaram, Vajjala K. Suman, Tapan K. Sengupta
Summary: Rayleigh-Taylor instability refers to the instability that occurs when the interface between two fluids of different densities is removed and the heavier fluid rests on top of the lighter fluid in the equilibrium state. This instability has been observed at various length scales, from nuclear fusion to astrophysical phenomena like supernova explosions. A non-overlapping parallel algorithm is used to simulate the three-dimensional Rayleigh-Taylor instability problem, providing insights into the vorticity creation and the dominance of viscous terms in the compressible flow.
Article
Mechanics
Xin Tong, Bo Lian, Peixiang Yu, Xiaoqing Qiang, Hua Ouyang
Summary: The effect of leading-edge shape on separation-induced transition on the suction surface is investigated through large eddy simulation. Two compressor controlled-diffusion airfoils with different leading-edge shapes are simulated, and two transitions are observed on the suction surface. The primary difference between the two airfoils lies in the leading-edge transition, which also leads to the distinction of fluctuating velocity amplitude and energy loss in the subsequent development of boundary layer flow.
Article
Mechanics
Luo Xie, Lang Jiang, Fan-Zhe Meng, Qiang Li, Jun Wen, Hai-Bao Hu
Summary: Bionic coatings composed of gelatin-polysaccharide mixtures have been developed to reduce drag in turbulent flow. The release rate of polysaccharides and the properties of gelatin proportionally affect the drag reduction efficiency of the coatings. Further research is needed to clarify the underlying mechanisms and improve the application potential of these biomimetic coatings.
Article
Physics, Multidisciplinary
Sauro Succi
Summary: This article discusses the possibility that the complexity of biological systems may exceed the predictive capabilities of theoretical physics, suggesting that the World Beyond Physics is smaller than expected based on fundamental physical theories.
Article
Chemistry, Physical
Francesco Di Palma, Sergio Decherchi, Fatima Pardo-Avila, Sauro Succi, Michael Levitt, Gunnar von Heijne, Andrea Cavalli
Summary: This study used all-atom molecular dynamics simulations to investigate the interactions between the XBP1u AP and the mammalian ribosome exit tunnel, shedding light on the ribosome stalling mechanism. The results provide an unprecedented atomistic picture of this biological process and offer insights into the key AP-ribosome interactions.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Polymer Science
Michele Monteferrante, Adriano Tiribocchi, Sauro Succi, Dario Pisignano, Marco Lauricella
Summary: This study investigates the free radical polymerization of photocurable polymers using reactive classical molecular dynamics combined with a dynamical approach of the nonequilibrium molecular dynamics (D-NEMD) method. The results provide insights into the physical and topological properties of the polymer and predict its mechanical behavior. This approach offers a novel tool to describe photopolymerization processes and optimize additive manufacturing methods.
Article
Chemistry, Physical
Abigail Rendos, Wenhan Cao, Margaret Chern, Marco Lauricella, Sauro Succi, Jorg G. Werner, Allison M. Dennis, Keith A. Brown
Summary: A suspension of nanoparticles can assemble into a macroscopic cellular phase that consists of particle-rich walls and particle-free voids under the influence of AC and DC voltages. This mechanism involves electrophoretic assembly and electrohydrodynamic flow-mediated spinodal decomposition. This work not only reveals the mechanism of cellular phase formation, but also presents a method to reversibly assemble nanoscale particles into microscale continuous structures.
Article
Physics, Multidisciplinary
Pablo G. Tello, D. O. N. A. T. O. Bini, S. T. U. A. R. T. Kauffman, S. A. U. R. O. Succi
Summary: This letter proposes an approach to the vacuum energy and the cosmological constant (CC) paradox based on the Zel'dovich's ansatz, which states that the observable contribution to the vacuum energy density is given by the gravitational energy of virtual particle-antiparticle pairs. The novelty of this work is the use of an ultraviolet cut-off length based on the holographic principle, which yields current values of the CC in semi-quantitative agreement with experimental observations.
Article
Physics, Mathematical
Daniele Simeoni, Alessandro Gabbana, Sauro Succi
Summary: In this work, we provide both analytic and numerical solutions for the Bjorken flow, which is a standard benchmark in relativistic hydrodynamics. It offers a simple model for the macroscopic evolution of matter produced in heavy nucleus collisions. We consider relativistic gases with both massive and massless particles, working in a (2+1) and (3+1) Minkowski spacetime coordinate system. The numerical results obtained from a newly developed lattice kinetic scheme show excellent agreement with the analytic solutions.
COMMUNICATIONS IN COMPUTATIONAL PHYSICS
(2023)
Article
Physics, Mathematical
Giacomo Falcucci, Giorgio Amati, Pierluigi Fanelli, Sauro Succi, Maurizio Porfiri
Summary: This study investigates the flow characteristics of the Hexactinellid Sponge Euplectella aspergillum using large-scale simulations. The findings reveal the evolutionary adaptations of deep-sea sponges to fluid flow and open up new possibilities for interdisciplinary research in physics, engineering, and biology at the ocean interface.
COMMUNICATIONS IN COMPUTATIONAL PHYSICS
(2023)
Article
Chemistry, Physical
Mihir Durve, Sibilla Orsini, Adriano Tiribocchi, Andrea Montessori, Jean-Michel Tucny, Marco Lauricella, Andrea Camposeo, Dario Pisignano, Sauro Succi
Summary: Tracking droplets in microfluidics is a challenging task, and choosing a tool to analyze microfluidic videos is difficult. The YOLO and DeepSORT algorithms are used for droplet identification and tracking by training networks. Several YOLOv5 and YOLOv7 models and the DeepSORT network were trained for droplet tracking. Performance comparison between YOLOv5 and YOLOv7 in terms of training time and video analysis time was conducted. Real-time tracking was achieved with lighter YOLO models on RTX 3070 Ti GPU due to additional droplet tracking costs from the DeepSORT algorithm. This work serves as a benchmark study for YOLOv5 and YOLOv7 networks with DeepSORT for microfluidic droplet analysis.
EUROPEAN PHYSICAL JOURNAL E
(2023)
Article
Chemistry, Physical
Adriano Tiribocchi, Andrea Montessori, Giorgio Amati, Massimo Bernaschi, Fabio Bonaccorso, Sergio Orlandini, Sauro Succi, Marco Lauricella
Summary: A regularized version of the lattice Boltzmann method is proposed for efficient simulation of soft materials. It reconstructs the distribution functions from available hydrodynamic variables without storing the full set of discrete populations, leading to lower memory requirements and data access costs. Benchmark tests validate the method's effectiveness for simulating soft matter systems, particularly on future exascale computers.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Mechanics
A. Tiribocchi, M. Durve, M. Lauricella, A. Montessori, D. Marenduzzo, S. Succi
Summary: Active droplets are artificial microswimmers that exhibit self-propelled motion. The authors study the effect of activity on a droplet containing a contractile polar fluid confined within microfluidic channels of various sizes. They find a range of shapes and dynamic regimes, regulated by contractile stress, droplet elasticity, and microchannel width.
Article
Physics, Particles & Fields
Andrea Solfanelli, Stefano Ruffo, Sauro Succi, Nicolo Defenu
Summary: In this study, we investigate the asymptotic behavior of the entanglement entropy for Kitaev chains with long-range hopping and pairing couplings. We find that the system exhibits an extremely rich phenomenology due to its truly non-local nature. In the strong long-range regime, we observe logarithmic, fractal, or volume-law entanglement scaling depending on the values of the chemical potential and power law decay strength.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Astronomy & Astrophysics
Donato Bini, Stuart Kauffman, Pablo G. Tello, Sauro Succi
Summary: In this study, we compute the metric fluctuations induced by a turbulent energy-matter tensor within the first order post-Minkowskian approximation. We find that the turbulent energy cascade can interfere with the process of black hole formation and exhibit a potentially strong coupling between these two highly nonlinear phenomena. Furthermore, we discover that the power-law turbulent energy spectrum determines the scaling of metric fluctuations as xn-2, with x representing the four-dimensional spacelike distance in Minkowski spacetime and highlighting metric singularities when n < 2. Finally, we discuss the effect of metric fluctuations on the geodesic motion of test particles as a potential technique to extract information on the spectral characteristics of fluctuating spacetime.
Article
Mathematics
Mihir Durve, Andriano Tiribocchi, Andrea Montessori, Marco Lauricella, Sauro Succi
Summary: This work analyzes the trajectories obtained from YOLO and DeepSORT algorithms in dense emulsion systems simulated using lattice Boltzmann methods. The findings reveal that the direction of individual droplets is more influenced by those immediately behind rather than in front of them. The analysis also provides insights into the constraints of a dynamical model for dense emulsions in narrow channels.
COMMUNICATIONS IN APPLIED AND INDUSTRIAL MATHEMATICS
(2022)
Article
Physics, Fluids & Plasmas
Harald Schmid, Johannes Dieplinger, Andrea Solfanelli, Sauro Succi, Stefano Ruffo
Summary: In this study, we generalize the classical Hamiltonian mean-field model to fermionic particles and investigate the phase diagram and thermodynamic properties of the model under ferromagnetic interactions. The system exhibits different quantum phase transition behaviors at different temperatures and a tricritical point is observed in a quantum system with long-range couplings.
Article
Physics, Fluids & Plasmas
Wael Itani, Sauro Succi
Summary: We explore the Carleman linearization of the collision term in the lattice Boltzmann formulation, aiming to develop a quantum lattice Boltzmann algorithm. The impact of linearization on the accuracy of the algorithm and the number of variables is studied for the case of an incompressible fluid. The results show that the error arising from Carleman linearization improves exponentially with the order of linearization, which is promising for the development of a quantum computing algorithm based on the lattice Boltzmann equation.
