Article
Physics, Fluids & Plasmas
Masato Itami, Yohei Nakayama, Naoko Nakagawa, Shin-ichi Sasa
Summary: We studied the fluctuating dynamics of a freely movable piston separating an infinite cylinder filled with ideal gas particles at different temperatures. By perturbatively calculating the large deviation function of the time-averaged velocity, we derived an infinite number of effective Langevin equations yielding the same large deviation function as in the original model. Finally, we provided two possibilities for uniquely determining the form of the effective model.
Article
Thermodynamics
Elena N. Vilchevskaya, Wolfgang H. Muller, Victor A. Eremeyev
Summary: In his work on generalized continuum mechanics, Eringen introduced the 3M theories of micromorphic, microstretch, and micropolar materials modeling, providing a comprehensive framework for studying continuum with different degrees of freedom. The extended micropolar theory further expands on this concept, allowing for a more flexible description of structural changes in material systems. By comparing these theories, the paper highlights their similarities and differences, showing the strengths and limitations of each approach.
CONTINUUM MECHANICS AND THERMODYNAMICS
(2022)
Article
Physics, Multidisciplinary
Eddy Collin, Ilya Golokolenov, Olivier Maillet, Laurent Saminadayar, Olivier Bourgeois
Summary: This study reports on the theoretical derivation of macroscopic thermal properties of an electrically insulating rod connected to two reservoirs. The theory predicts the temperature gradient and energy transport by linking motion amplitude cross-correlations between nearby mechanical modes. The theory relates the macroscopic clamping region where mixing occurs to the microscopic phonon mean-free-path.
NEW JOURNAL OF PHYSICS
(2023)
Article
Mathematics, Applied
Francisco J. Suarez-Grau
Summary: This study examines the flow of a micropolar fluid in a medium perforated by periodically distributed obstacles of size epsilon. A nonhomogeneous boundary condition for microrotation is considered, with microrotation assumed to be proportional to the rotation rate of the velocity on the boundary of the obstacles. The existence and uniqueness of solution are analyzed, and an analog of the classical micropolar Darcy's law in the theory of porous media is derived in the limit as epsilon tends to zero.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2021)
Article
Engineering, Aerospace
Hassan Waqas, Shan Ali Khan, Bagh Ali, Dong Liu, Taseer Muhammad, Enran Hou
Summary: The current article investigates the numerical study of the micropolar nanofluid flow through a 3D rotating surface. The effects of heat source/sink, Brownian motion, thermophoresis, Darcy-Forchheimer law, and activation energy are analyzed. The numerical analysis is simplified with the help of resemblance transformations and MATLAB software. The results show the impact of different physical factors on the flow profile and temperature gradient.
PROPULSION AND POWER RESEARCH
(2023)
Article
Mechanics
Vandana Mishra, Bali Ram Gupta
Summary: This study investigates the slow steady axisymmetric flow of an incompressible non-Newtonian micropolar fluid around and through a swarm of permeable spherical particles in a cell using a cell model technique. Analytical solutions for the flow fields are obtained using the stream function solutions of Stokes equation. The numerical results show the pressure distribution, microrotation components, drag force, flow rate, and wall correction factor, and their variations with different fluid parameters are presented and discussed. The drag force, flow rate, and wall correction factor are found to be greater in the Kuwabara model compared to the Kvashnin model.
ARCHIVE OF APPLIED MECHANICS
(2022)
Article
Materials Science, Multidisciplinary
Koh-hei Nitta
Summary: The plastic deformation of solid polymers can be effectively explained by the Eyring activated rate theory, which involves the movement of cooperative mobile elements over potential barriers. The current study demonstrates that the governing equations for the Eyring rate theory can be derived through the principle of microscopic reversibility in the context of non-equilibrium dynamics.
PHILOSOPHICAL MAGAZINE LETTERS
(2023)
Article
Chemistry, Physical
Massoud Hassanabadi, Thomas Berto, Shahid Akhtar, Ragnhild E. Aune
Summary: In this study, the physical and hydraulic characteristics of alumina-based ceramic foam filters (CFF) from three different suppliers were investigated. It was found that there were significant variations in morphological and hydraulic properties of CFFs with identical Grade and PPI numbers. A model equation was developed to calculate the pressure drop over CFFs using the Window Feret diameter.
Article
Physics, Multidisciplinary
Nahuel Freitas, Jean-Charles Delvenne, Massimiliano Esposito
Summary: A general theory of nonlinear electronic circuits subjected to thermal noise is provided, involving devices like tunnel junctions, diodes, and MOS transistors in subthreshold operation. The stochastic nonequilibrium thermodynamics of these circuits is established, with irreversible entropy production expressed in terms of thermodynamic potentials and forces, and its fluctuations satisfying fluctuation theorems. The theory is shown to be applicable in formulating a thermodynamics of computing with realistic architectures, where thermal fluctuations play an increasingly important role due to reduction in transistor size and operating voltages.
Article
Mathematics, Interdisciplinary Applications
Lucero Damian Adame, Claudia del Carmen Gutierrez-Torres, Bernardo Figueroa-Espinoza, Juan Gabriel Barbosa-Saldana, Jose Alfredo Jimenez-Bernal
Summary: The main goal of this manuscript is to generalize Darcy's law from conventional calculus to fractal calculus in order to quantify fluid flow in subterranean heterogeneous reservoirs. The fractal continuum Darcy's law is suggested based on the mapping of the fractal reservoir domain to the corresponding fractal continuum domain using local fractional differential operators. The equation captures the fractal heterogeneity and anisotropy and can be collapsed to the classical Darcy's law when a certain parameter is selected. The results show good agreement with experimental data and the model provides insights into the flow behavior in porous media.
FRACTAL AND FRACTIONAL
(2023)
Article
Mathematics, Applied
Patrick De Leenheer, John Musgrove, Tyler Schimleck
Summary: Bertrand's Theorem in Newtonian mechanics states that there are only two gravitational laws, Newtonian gravitation and Hookean gravitation, that have the property of all bounded orbits being closed. We provide a comprehensive proof of the theorem that can be understood by undergraduate students with knowledge of advanced calculus and differential equations.
Article
Mathematics, Interdisciplinary Applications
Roberto Palma, Jose L. Perez-Aparicio, Robert L. Taylor
Summary: The main aim of this work is to study the role of the Maxwell stress tensor in active materials. In the framework of generalised continuum mechanics, a modified total stress formulation is developed and implemented into a finite element research code. It is concluded that generalised mechanics allows for incorporating both symmetric and non-symmetric contributions of the Maxwell tensor, enabling the analysis of rotations generated by the electromagnetic field.
COMPUTATIONAL MECHANICS
(2023)
Article
Mechanics
Farui Shi, Nicholas Fantuzzi, Yong Li, Patrizia Trovalusci, Zuoan Wei
Summary: The purpose of this study is to investigate the dilatancy effect on the mechanical behavior of layered rock structures with rough interfaces. Using interfaces with various roughness, the dilatancy effect is evaluated and the contact density model is used to estimate the stiffness properties of rough surfaces. The problem is analyzed using finite element numerical codes to demonstrate the validity of the combination of dilatancy models and micropolar theory for layered rock structures.
MECHANICS RESEARCH COMMUNICATIONS
(2022)
Article
Energy & Fuels
Huifang Hu, Tian Shen, Naiyuan Zheng, Xinpu Shen, Jinbiao Yu
Summary: This paper presents a method for modeling natural fractures using continuum damage tensor and proposes a damage-dependent permeability tensor. The results indicate that the model can effectively simulate the fracture propagation phenomena during hydraulic fracturing.
Article
Mathematics, Applied
Eduard Marusic-Paloka, Igor Pazanin
Summary: The effects of roughness on the Darcy boundary condition for the Stokes system are investigated using rigorous asymptotic analysis and homogenization techniques. By considering a domain with a porous boundary that is periodically oscillating, the effective permeability as a function of roughness is determined.
ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND PHYSIK
(2023)