Article
Mathematics, Applied
Celestine Woodruff
Summary: In this work, we analyzed a numerical scheme for the infinite Prandtl number model for convection, aiming to estimate the scaling of the Nusselt number. We presented a semi-implicit scheme that can adequately capture the long time statistical properties of the model, with good stability and dissipative characteristics.
JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS
(2022)
Article
Mechanics
C. Jain, V. S. Solomatov
Summary: We investigate the onset of convection in internally heated fluids with strongly temperature-dependent viscosity. As the viscosity contrast increases, a high-viscosity stagnant lid develops at the upper surface and convection occurs in a sublayer beneath it. The results of this study can help improve our understanding of the conditions under which convection occurs in planetary interiors.
Article
Physics, Multidisciplinary
Felix Schindler, Sven Eckert, Till Zuerner, Joerg Schumacher, Tobias Vogt
Summary: In highly turbulent liquid metal convection experiments, the large-scale flow structure and the turbulent transfer of heat and momentum were directly measured. It was found that the aspect ratio has a significant impact on the scaling laws for heat and momentum transfer.
PHYSICAL REVIEW LETTERS
(2022)
Article
Mechanics
Megumi Akashi, Takatoshi Yanagisawa, Ataru Sakuraba, Felix Schindler, Susanne Horn, Tobias Vogt, Sven Eckert
Summary: The study examines the topology and temporal dynamics of turbulent Rayleigh-Benard convection in a liquid metal with a low Prandtl number inside a box with specific dimensions. Results show similarities to the jump rope vortex structure discovered in a different configuration, with the coexistence of multiple recirculating swirls. This complex flow behavior leads to variations in velocity and Nusselt number oscillations.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Thermodynamics
Sheng Chen, Wenhao Li, Hayder Mohammed
Summary: This study investigates the heat transfer characteristics of natural convection of large Prandtl number fluids in porous media using a novel lattice Boltzmann approach. It reveals significant differences between large and small Prandtl number fluids, with the former more easily transitioning from a convection-dominated process to a conduction-dominated one in porous media.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Mechanics
C. N. Onyeador, A. Hodge, W. Harris
Summary: This study examines the Lees-Dorodnitsyn (L-D) boundary layer equations for hypersonic boundary layer flows and develops a novel methodology for computing high-temperature hypersonic flows. The proposed methodology uses a computational tool called BuBL solver and considers the impact of high-temperature effects on hypersonic flows. The results show excellent agreement between the proposed methodology and other computational fluid dynamics and experimental results.
Article
Physics, Fluids & Plasmas
Nisar Ahmad, Ping Zhu, Ahmad Ali, Shiyong Zeng
Summary: The evolution of a highly unstable m = 1 resistive tearing mode, leading to plasmoid formation in a Harris sheet, is studied in this work using the Non-Ideal Magnetohydrodynamics with Rotation, Open Discussion simulation. Two distinctive viscous regimes are found for the plasmoid formation and saturation, with the plasmoid width increasing sharply with viscosity in the low viscosity regime and gradually decreasing with viscosity in the viscosity dominant regime. The role of viscosity in modulating the plasmoid formation process through its effects on the plasma flow and reconnection is quantified.
PLASMA SCIENCE & TECHNOLOGY
(2022)
Article
Geochemistry & Geophysics
Amy L. Ferrick, Jun Korenaga
Summary: Convection in planetary mantles is driven by heating from below and from within, making the parameterization of heat flux for mixed heated convection challenging. While scaling laws for internal and basal heating have been determined, their applicability to mixed heated convection has been questioned. This study presents a scaling approach that incorporates the physics of convection and successfully describes relationships between thermal boundary layer properties for mixed heated convection.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Thermodynamics
F. Alcantara-Avila, S. Hoyas
Summary: A new set of DNS experiments were conducted on a thermal channel flow, covering friction Reynolds and Prandtl numbers up to 2000 and 10, reaching a Prandtl number of 7 for water and introducing a new scale for the conductive sublayer thickness. The thermal field intensity does not increase with Reynolds number for highest Prandtl numbers, indicating good scaling near the wall. The Nusselt number shows a power function behavior with respect to Prandtl number in a certain range of the friction Peclet number, with turbulent Prandtl number increasing near the wall for highest Prandtl numbers due to reduction in thermal eddy diffusivity.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Nuclear Science & Technology
Boshen Bian, Walter Villanueva, Daniele Dovizio
Summary: This paper presents a Direct Numerical Simulation of an internally heated natural convection in a 3D semicircular slice molten pool using Nek5000. The simulation results are consistent with experimental observations. The velocity and temperature fields show different characteristics in different regions, and the heat flux distribution and Prandtl number affect the heat transfer.
NUCLEAR ENGINEERING AND DESIGN
(2022)
Article
Energy & Fuels
Asif Afzal, Rahul Kumar, R. D. Jilte, Mohammed Samee, Saboor Shaik, R. K. Abdul Razak, A. Muthu Manokar, C. Ahamed Saleel
Summary: This study analyzed a system of parallelly placed Li-ion batteries with different spacings and cooled by different coolants. The focus was on the effect of battery spacing on battery thermal performance. The study used numerical analysis and experimental validation to investigate the impact of coolant Prandtl number on heat transfer characteristics.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2022)
Article
Thermodynamics
Y. El Khchine, M. Sriti
Summary: A numerical analysis is conducted to investigate the forced convective fluid flow and heat transfer on an unconfined semicircular cylinder. The study reveals the effect of Reynolds number on heat transfer and presents a developed correlation between Nu and St numbers.
NUMERICAL HEAT TRANSFER PART A-APPLICATIONS
(2023)
Article
Thermodynamics
I. Rodriguez, A. Campo
Summary: The study investigates the effects of Prandtl number on forced convective heat transfer around a sphere, showing that at lower Prandtl numbers, diffusive effects become important, resulting in a lower decay ratio of temperature in the wake centerline and a larger wake spread compared to higher Prandtl numbers.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Engineering, Multidisciplinary
Haiying Zhang, Xiujun Nie, Dmitry Olegovich Bokov, Davood Toghraie, Omid Ali Akbari, Farnaz Montazerifar, Farzad Pourfattah, Yousof Esmaeili, Roohollah Khodaparast
Summary: In this study, laminar mixed convection of water/Ag nanofluid with different volume fractions of nanoparticles was simulated. The results show that adding a higher volume fraction of nanoparticles at lower Richardson numbers enhances heat transfer and Nusselt number. The streamlines in the cavity are influenced by lid-driven motion and fluid viscosity, which contribute to achieving uniform temperature distribution in the cavity.
ALEXANDRIA ENGINEERING JOURNAL
(2022)
Article
Engineering, Chemical
Saswat Kumar Nayak, Sourav Mondal
Summary: This study introduces a new viscosity correction in non-Newtonian fluid based on fundamental boundary layer analysis, validated with literature experimental data. Accurate estimation of viscosity correction is crucial for predicting heat transfer coefficient, affecting effective heat transfer area.
CHEMICAL ENGINEERING SCIENCE
(2021)
Article
Mechanics
Santiago Madruga, Jezabel Curbelo
Summary: This study investigates the effect of inclination on the transient heat transfer, flow, and melting dynamics of a phase change material within a square domain through two-dimensional simulations and analytic results. The tilt determines the stability threshold of the base state, leading to either laminar flow or turbulent states depending on the critical inclination. The turbulent regime exhibits higher dispersion in quantities related to heat transfer and flow dynamics on smaller domains.
Article
Mathematics, Applied
G. Garcia-Sanchez, A. M. Mancho, S. Wiggins
Summary: A new quantifier for forward time uncertainty of trajectories from data-generated models is developed, showing rich structure in phase space related to dynamical systems theory. Application to ocean data sets allows quantitative comparison of transport performance, providing avenues for effective use of various data sources.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2022)
Article
Geochemistry & Geophysics
Yanick Ricard, Thierry Alboussiere, Stephane Labrosse, Jezabel Curbelo, Fabien Dubuffet
Summary: Numerical simulations of convection inside the Earth's mantle or terrestrial planets are often based on approximate fluid dynamics equations. The Boussinesq approximation (BA) and anelastic approximation (AA) are commonly used, but they can lead to theoretical inconsistencies. This study shows that solving the fully compressible (FC) equations with a realistic equation of state (EoS) is not significantly more difficult than solving the approximate cases. It also highlights an inconsistency in the AA approximation when assuming constant heat capacities.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Mechanics
Thierry Alboussiere, Jezabel Curbelo, Fabien Dubuffet, Stephane Labrosse, Yanick Ricard
Summary: This study investigates the basic characteristics of compressible convection by considering a unique equation of state. Numerical simulations reveal that the vertical temperature profile changes and the strength of ascending plumes weakens within a certain range of parameters. Additionally, this framework is proposed for predicting the dissipation profile and the ratio of dissipation to convective heat flux.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Multidisciplinary Sciences
Guillermo Garcia-Sanchez, Ana M. Mancho, Antonio G. Ramos, Josep Coca, Stephen Wiggins
Summary: The chaotic nature of ocean motion hinders the discovery of material transport routes. Oil spills pose significant threats to the environment, and their origins are often unpredictable. The use of Lagrangian Coherent Structures helps find order within ocean chaos and provides insights for addressing similar issues.
SCIENTIFIC REPORTS
(2022)
Article
Mathematics, Interdisciplinary Applications
Matthaios Katsanikas, Makrina Agaoglou, Stephen Wiggins, Ana M. Mancho
Summary: This study applies the method of Lagrangian Descriptors to a symmetric Caldera-type potential energy surface, analyzing the phase space transport mechanism that explains the existence and nonexistence of dynamical matching phenomenon for this form of potential energy surface.
INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS
(2022)
Article
Mathematics, Applied
Jerome Daquin, Remi Pedenon-Orlanducci, Makrina Agaoglou, Guillermo Garcia-Sanchez, Ana Maria Mancho
Summary: This paper introduces a new global dynamics and chaos indicator suitable for discriminating ordered and deterministic chaotic motions in multidimensional systems. The indicator appears to be relevant for understanding phase space transport mediated by resonances in nearly-integrable systems.
PHYSICA D-NONLINEAR PHENOMENA
(2022)
Correction
Mathematics, Applied
Guillermo Garcia-Sanchez, Ana M. Mancho, Stephen Wiggins
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2023)
Article
Geosciences, Multidisciplinary
Renzo Bruera, Jezabel Curbelo, Guillermo Garcia-Sanchez, Ana M. Mancho
Summary: This study explores 3D conveyor routes associated with the Atlantic Meridional Overturning Circulation (AMOC), using Lagrangian Coherent Structures. The findings reveal the geometry of mixing structures in the upper and deep ocean layers and identify regions linked to vertical transport, characterizing transport time scales. The study focuses on the Flemish Cap region and the Irminger Sea, uncovering rapid upward ascension of deep waters and a previously unreported upwelling connection between very deep waters and the ocean surface.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Mathematics, Applied
Narjisse Amahjour, Guillermo Garcia-Sanchez, Makrina Agaoglou, Ana Maria Mancho
Summary: This research paper uses computational fluid dynamics (CFD) and Lagrangian Coherent Structures (LCS) to analyze the propagation of SARS-CoV-2 or similar pathogens in a hospital isolation room. The study examines the dispersion of airflow and droplets under air conditioning vent and sanitizer conditions. The CFD simulation results demonstrate the significant influence of the air conditioner and sanitizer systems on virus dispersion in the room. The use of LCS provides insights into the mechanisms of virus transmission by understanding the dispersion of suspended particles. The findings of this study can contribute to the improvement of isolation room design and operation strategies to minimize virus dissemination within hospitals.
PHYSICA D-NONLINEAR PHENOMENA
(2023)
Correction
Multidisciplinary Sciences
Guillermo Garcia-Sanchez, Ana M. Mancho, Antonio G. Ramos, Josep Coca, Stephen Wiggins
SCIENTIFIC REPORTS
(2023)
Correction
Environmental Sciences
Guillermo Garcia-Sanchez, Ana M. Mancho, Antonio G. Ramos, Josep Coca, Begona Perez-Gomez, Enrique Alvarez-Fanjul, Marcos G. Sotillo, Manuel Garcia-Leon, Victor J. Garcia-Garrido, Stephen Wiggins
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Mathematics, Applied
Guillermo Garcia-Sanchez, Ana Maria Mancho, Makrina Agaoglou, Stephen Wiggins
Summary: This paper proposes a new uncertainty measure that can be used to assess the performance of transport models in determining the origin or source of a given observation. The study reveals that the proposed measure of uncertainty is linked to the invariant dynamical structures of the model within the vicinity of the observation. The paper also demonstrates the application of this proposed method in evaluating the performance of ocean data sets during an actual oil spill event in the Eastern Mediterranean in 2021.
PHYSICA D-NONLINEAR PHENOMENA
(2023)
Article
Meteorology & Atmospheric Sciences
Aman Gupta, Marianna Linz, Jezabel Curbelo, Olivier Pauluis, Edwin P. Gerber, Douglas E. Kinnison
Summary: Wave-induced adiabatic mixing in the winter midlatitudes is a key process affecting stratospheric transport. This study proposes refinements to the vertical age gradient theory to quantify the mixing flux, taking into account meridional tracer gradients. The revised theory reveals an underestimation of the wave-driven mixing flux when ignoring these gradients.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Mathematics, Applied
Hao Liu, Yuzhe Li
Summary: This paper investigates the finite-time stealthy covert attack on reference tracking systems with unknown-but-bounded noises. It proposes a novel finite-time covert attack method that can steer the system state into a target set within a finite time interval while being undetectable.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)
Article
Mathematics, Applied
Nikolay A. Kudryashov, Aleksandr A. Kutukov, Sofia F. Lavrova
Summary: The Chavy-Waddy-Kolokolnikov model with dispersion is analyzed, and new properties of the model are studied. It is shown that dispersion can be used as a control mechanism for bacterial colonies.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)
Article
Mathematics, Applied
Qiang Ma, Jianxin Lv, Lin Bi
Summary: This paper introduces a linear stability equation based on the Boltzmann equation and establishes the relationship between small perturbations and macroscopic variables. The numerical solutions of the linear stability equations based on the Boltzmann equation and the Navier-Stokes equations are the same under the continuum assumption, providing a theoretical foundation for stability research.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)
Article
Mathematics, Applied
Samuel W. Akingbade, Marian Gidea, Matteo Manzi, Vahid Nateghi
Summary: This paper presents a heuristic argument for the capacity of Topological Data Analysis (TDA) to detect critical transitions in financial time series. The argument is based on the Log-Periodic Power Law Singularity (LPPLS) model, which characterizes financial bubbles as super-exponential growth (or decay) with increasing oscillations approaching a tipping point. The study shows that whenever the LPPLS model fits the data, TDA generates early warning signals. As an application, the approach is illustrated using positive and negative bubbles in the Bitcoin historical price.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)
Article
Mathematics, Applied
Xavier Antoine, Jeremie Gaidamour, Emmanuel Lorin
Summary: This paper is interested in computing the ground state of nonlinear Schrodinger/Gross-Pitaevskii equations using gradient flow type methods. The authors derived and analyzed Fractional Normalized Gradient Flow methods, which involve fractional derivatives and generalize the well-known Normalized Gradient Flow method proposed by Bao and Du in 2004. Several experiments are proposed to illustrate the convergence properties of the developed algorithms.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)
Article
Mathematics, Applied
Lianwen Wang, Xingyu Wang, Zhijun Liu, Yating Wang
Summary: This contribution presents a delayed diffusive SEIVS epidemic model that can predict and quantify the transmission dynamics of slowly progressive diseases. The model is applied to fit pulmonary tuberculosis case data in China and provides predictions of its spread trend and effectiveness of interventions.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)
Article
Mathematics, Applied
Shuangxi Huang, Feng-Fei Jin
Summary: This paper investigates the error feedback regulator problem for a 1-D wave equation with velocity recirculation. By introducing an invertible transformation and an adaptive error-based observer, an observer-based error feedback controller is constructed to regulate the tracking error to zero asymptotically and ensure bounded internal signals.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)
Article
Mathematics, Applied
Weimin Liu, Shiqi Gao, Feng Xu, Yandong Zhao, Yuanqing Xia, Jinkun Liu
Summary: This paper studies the modeling and consensus control of flexible wings with bending and torsion deformation, considering the vibration suppression as well. Unlike most existing multi-agent control theories, the agent system in this study is a distributed parameter system. By considering the mutual coupling between the wing's deformation and rotation angle, the dynamics model of each agent is expressed using sets of partial differential equations (PDEs) and ordinary differential equations (ODEs). Boundary control algorithms are designed to achieve control objectives, and it is proven that the closed-loop system is asymptotically stable. Numerical simulation is conducted to demonstrate the effectiveness of the proposed control scheme.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)
Article
Mathematics, Applied
Gourav Mandal, Lakshmi Narayan Guin, Santabrata Chakravarty
Summary: The ecological framework investigates the dynamical complexity of a system influenced by prey refuge and alternative food sources for predators. This study provides a thorough investigation of the stability-instability phenomena, system parameters sensitivity, and the occurrence of bifurcations. The bubbling phenomenon, which indicates a change in the amplitudes of successive cycles, is observed in the current two-dimensional continuous system. The controlling system parameter for the bubbling phenomena is found to be the most sensitive. The prediction and identification of bifurcations in the dynamical system are crucial for theoretical and field researchers.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)
Article
Mathematics, Applied
Damian Trofimowicz, Tomasz P. Stefanski, Jacek Gulgowski, Tomasz Talaska
Summary: This paper presents the application of control engineering methods in modeling and simulating signal propagation in time-fractional electrodynamics. By simulating signal propagation in electromagnetic media using Maxwell's equations with fractional-order constitutive relations in the time domain, the equations in time-fractional electrodynamics can be considered as a continuous-time system of state-space equations in control engineering. Analytical solutions are derived for electromagnetic-wave propagation in the time-fractional media based on state-transition matrices, and discrete time zero-order-hold equivalent models are developed and their analytical solutions are derived. The proposed models yield the same results as other reference methods, but are more flexible in terms of the number of simulation scenarios that can be tackled due to the application of the finite-difference scheme.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)
Article
Mathematics, Applied
Yuhao Zhao, Fanhao Guo, Deshui Xu
Summary: This study develops a vibration analysis model of a nonlinear coupling-layered soft-core beam system and finds that nonlinear coupling layers are responsible for the nonlinear phenomena in the system. By using reasonable parameters for the nonlinear coupling layers, vibrations in the resonance regions can be reduced and effective control of the vibration energy of the soft-core beam system can be achieved.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)
Article
Mathematics, Applied
S. Kumar, H. Roy, A. Mitra, K. Ganguly
Summary: This study investigates the nonlinear dynamic behavior of bidirectional functionally graded plates (BFG) and unidirectional functionally graded plates (UFG). Two different methods, namely the whole domain method and the finite element method, are used to formulate the dynamic problem. The results show that all three plates exhibit hardening type nonlinearity, with the effect of material gradation parameters being more pronounced in simply supported plates.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)
Article
Mathematics, Applied
Isaac A. Garcia, Susanna Maza
Summary: This paper analyzes the role of non-autonomous inverse Jacobi multipliers in the problem of nonexistence, existence, localization, and hyperbolic nature of periodic orbits of planar vector fields. It extends and generalizes previous results that focused only on the autonomous or periodic case, providing novel applications of inverse Jacobi multipliers.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)
Article
Mathematics, Applied
Yongjian Liu, Yasi Lu, Calogero Vetro
Summary: This paper introduces a new double phase elliptic inclusion problem (DPEI) involving a nonlinear and nonhomogeneous partial differential operator. It establishes the existence and extremality results to the elliptic inclusion problem and provides definitions for weak solutions, subsolutions, and supersolutions.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)
Article
Mathematics, Applied
Shangshuai Li, Da-jun Zhang
Summary: In this paper, the Cauchy matrix structure of the spin-1 Gross-Pitaevskii equations is investigated. A 2 x 2 matrix nonlinear Schrodinger equation is derived using the Cauchy matrix approach, serving as an unreduced model for the spin-1 BEC system with explicit solutions. Suitable constraints are provided to obtain reductions for the classical and nonlocal spin-1 GP equations and their solutions, including one-soliton solution, two-soliton solution, and double-pole solution.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2024)