CLASSICAL FLUID DYNAMICS UNDER MOLECULAR SCALE CONFINEMENT

2009 ◽  
Vol 23 (28) ◽  
pp. 3311-3331
Author(s):  
J. K. PERCUS
Keyword(s):  
Fluid Dynamics ◽  
Preliminary Analysis ◽  
Particle Dynamics ◽  
Point Particle ◽  
Particle Diffusion ◽  
One Dimensional ◽  
Single File ◽  
Molecular Scale ◽  
Recent Developments ◽  
Heuristic Analysis

This is a review of some recent developments in the theory of classical nanoscale fluid dynamics, with tagged particle dynamics as the signature of transport properties. A heuristic analysis of the time asymptotic regime in strictly one-dimensional flow is followed by an exact treatment of the same system, with arbitrary non-interacting point particle dynamics. Stretched time and space coordinates allow us to obtain a universal form — the telegrapher's equation — for the self-dynamics after transients have died down. Attention then shifts to one-particle diffusion in a spatially modulated tubular enclosure, which is analyzed by increasingly sophisticated approximation methods. With this background, single-file fluid flow in modulated enclosures is studied, and preliminary analysis of the "passing region" carried out as well.

Ratchet Effect and Particle Diffusion in an Underdamped Inhomogeneous Periodic Potential System

2020 ◽  
Vol 7 (1) ◽  
pp. 01-11
Author(s):  
Shantu Saikia ◽  
◽  
Francis Iawphniaw
Keyword(s):  
Periodic Potential ◽  
Thermal Fluctuations ◽  
Particle Dynamics ◽  
Particle Diffusion ◽  
Biological Processes ◽  
Ratchet Effect ◽  
External Bias ◽  
Potential System ◽  
Constructive Work ◽  
Random Fluctuations

Thermal fluctuations or noise assisted particle dynamics in a driven underdamped inhomogeneous periodic potential system is studied. This forms an archetypal model to study different Physical and Biological processes in the microscopic domain. The particles are shown to exhibit directed transport aided by these fluctuations without the application of any external bias. This phenomenon, also known as ratchet effect, is a counterintuitive phenomenon in which systems in the microscopic domain harnesses the energy of the random fluctuations to do constructive work. Also in the presence of random thermal fluctuations or noise, the particles undergo diffusion, the amount of which can be controlled by controlling the different parameters of the system. This can have important technological applications.

scholarly journals A Short Remark on Vortex as Fluid Particle from Neutrosophic Logic perspective (Towards “fluidicle” or “vorticle” model of QED.)

2020 ◽  
pp. 38-46
Author(s):  
Victor Christianto ◽  
◽  
◽  
Florentin Smarandache
Keyword(s):  
Fluid Dynamics ◽  
Maxwell Equations ◽  
Particle Dynamics ◽  
Fluid Particle ◽  
Alternative Approach ◽  
Neutrosophic Logic

In a previous paper in this journal (IJNS), it is mentioned about a possible approach to re-describe QED without renormalization route. As it is known that in literature, there are some attempts to reconcile vortex-based fluid dynamics and particle dynamics. Some attempts are not quite as fruitful as others. As a follow up to previous paper, the present paper will discuss two theorems for developing unification theories, and then point out some new proposals including by Simula (2020) on how to derive Maxwell equations in superfluid dynamics setting; this could be a new alternative approach towards “fluidicle” or “vorticle” model of QED. Further research is recommended in this new direction.

THE HALDANE GAP IN ANTIFERROMAGNETIC HEISENBERG CHAINS

1994 ◽  
Vol 06 (05a) ◽  
pp. 887-899 ◽  
Author(s):  
IAN AFFLECK
Keyword(s):  
Bose Condensation ◽  
Local Order ◽  
Rigorous Results ◽  
One Dimensional ◽  
Haldane Gap ◽  
Local Order Parameter ◽  
Recent Developments ◽  
Heisenberg Chains ◽  
Non Local ◽  
And Behavior

Integer-spin Heisenberg antiferromagnetic chains are expected to have a singlet groundstate and a gap to the first excited state, as first argued by Haldane. We review rigorous results on this conjecture and discuss experimental realizations. Theoretical and experimental aspects of three recent developments in this field are then reviewed: chainend excitations and the non-local order parameter, a field theory mapping and behavior near zero wave-vector, high-field behavior and one-dimensional Bose condensation.

The Mechanics and Thermodynamics of Steady One-Dimensional Gas Flow

1947 ◽  
Vol 14 (4) ◽  
pp. A317-A336 ◽  
Author(s):  
Ascher H. Shapiro ◽  
W. R. Hawthorne
Keyword(s):  
Heat Transfer ◽  
Dimensional Analysis ◽  
High Speed ◽  
Gas Flow ◽  
Gas Injection ◽  
Wall Friction ◽  
Analytical Treatment ◽  
Area Change ◽  
One Dimensional ◽  
Recent Developments

Abstract Recent developments in the fields of propulsion, flow machinery, and high-speed flight have emphasized the need for an improved understanding of the characteristics of compressible flow. A one-dimensional analysis for flow without shocks is presented which takes into account the simultaneous effects of area change, wall friction, drag of internal bodies, external heat exchange, chemical reaction, change of phase, injection of gases, and changes in molecular weight and specific heat. The method of selecting independent and dependent variables, and the organization of the working equations, leads, it is believed, to a better understanding of the influence of the foregoing effects, and also simplifies greatly the analytical treatment of particular problems. Examples are given first of several simple types of flow, including (a) area change only; (b) heat transfer only; (c) wall friction only; and (d) gas injection only. In addition, examples of flow with combined effects are given, including (a) simultaneous friction and area change; (b) simultaneous friction and heat transfer; and (c) simultaneous liquid injection and evaporation. A one-dimensional analysis for flow through a discontinuity is presented, allowing for energy, shock, drag, and gas-injection effects, and for changes in gas properties. This analysis is applicable to such processes as: (a) the adiabatic normal shock; (b) combustion; (c) moisture condensation shocks; and (d) steady explosion waves.

A flow-dependent estimation of constriction size distribution in gap-graded soils: an integrated statistical approach

2022 ◽  
Vol 12 (1) ◽  
pp. 1-25
Author(s):  
S.M. Dassanayake ◽  
A. Mousa
Keyword(s):  
Fluid Dynamics ◽  
Size Distribution ◽  
Statistical Approach ◽  
One Dimensional ◽  
Loading Pattern ◽  
Wide Range ◽  
Hydraulic Gradients ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations ◽  
Estimate Flow

The clogging-unclogging process in gap-graded soils is a result of the migration of seepage-driven fines, which subsequently induces measurable changes in the local hydraulic gradients. This process can be temporally observed in the variations of Darcy's hydraulic conductivity (K). The current study proposes an integrated statistical Monte Carlo approach combining the discrete element method and 2D computational fluid dynamics simulations to estimate the flow-dependent constriction size distribution (CSD) for a gap-graded soil. The computational inferences were supported with experimental results using an internally stable soil, which was subjected to one-dimensional flow stimulating desired hydraulic loadings: a hydraulic gradient lower than the critical gradient applied as a multi-staged loading pattern. The 35th percentile size of the flow-dependent CSD (Dc35) for both internally stable and unstable gap-graded soils becomes approximately equal to Dc35 at steady-state. However, a greater variation of larger constrictions persists for the unstable soils. This pilot study has shown the applicability of the proposed method to estimate flow-dependent CSD for a wide range of experimentally observed K values.

scholarly journals Structural and hemodynamic properties of murine pulmonary arterial networks under hypoxia-induced pulmonary hypertension

2020 ◽  
Vol 234 (11) ◽  
pp. 1312-1329 ◽  
Author(s):  
Megan J Chambers ◽  
Mitchel J Colebank ◽  
M Umar Qureshi ◽  
Rachel Clipp ◽  
Mette S Olufsen
Keyword(s):  
Fluid Dynamics ◽  
Blood Pressure ◽  
Pulmonary Hypertension ◽  
Pulmonary Artery ◽  
Main Pulmonary Artery ◽  
Branching Ratio ◽  
Microcomputed Tomography ◽  
Imaging Data ◽  
One Dimensional ◽  
Computed Tomography Images

Detection and monitoring of patients with pulmonary hypertension, defined as a mean blood pressure in the main pulmonary artery above 25 mmHg, requires a combination of imaging and hemodynamic measurements. This study demonstrates how to combine imaging data from microcomputed tomography images with hemodynamic pressure and flow waveforms from control and hypertensive mice. Specific attention is devoted to developing a tool that processes computed tomography images, generating subject-specific arterial networks in which one-dimensional fluid dynamics modeling is used to predict blood pressure and flow. Each arterial network is modeled as a directed graph representing vessels along the principal pathway to ensure perfusion of all lobes. The one-dimensional model couples these networks with structured tree boundary conditions representing the small arteries and arterioles. Fluid dynamics equations are solved in this network and compared to measurements of pressure in the main pulmonary artery. Analysis of microcomputed tomography images reveals that the branching ratio is the same in the control and hypertensive animals, but that the vessel length-to-radius ratio is significantly lower in the hypertensive animals. Fluid dynamics predictions show that in addition to changed network geometry, vessel stiffness is higher in the hypertensive animal models than in the control models.

REACTION-FRONT DYNAMICS IN A+B→C WITH INITIALLY-SEPARATED REACTANTS

Fractals ◽  
1993 ◽  
Vol 01 (03) ◽  
pp. 405-415 ◽  
Author(s):  
S. HAVLIN ◽  
M. ARAUJO ◽  
H. LARRALDE ◽  
A. SHEHTER ◽  
H.E. STANLEY
Keyword(s):  
Reaction Front ◽  
Reaction Rate ◽  
Reaction System ◽  
Diffusion Reaction ◽  
Dimensional System ◽  
Scaling Exponent ◽  
One Dimensional ◽  
Recent Developments ◽  
The One ◽  
Front Dynamics

We review recent developments in the study of the diffusion reaction system of the type A+B→C in which the reactants are initially separated. We consider the case where the A and B particles are initially placed uniformly in Euclidean space at x>0 and x<0 respectively. We find that whereas for d≥2 a single scaling exponent characterizes the width of the reaction zone, a multiscaling approach is needed to describe the one-dimensional system. We also present analytical and numerical results for the reaction rate on fractals and percolation systems.

Sign in / Sign up

Export Citation Format

Share Document