Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Entropy

Entropy

Salt particles that have dissolved in water never spontaneously come back together in solution to reform solid particles. Moreover, a gas that has expanded in a vacuum remains dispersed and never spontaneously reassembles. The unidirectional nature of these phenomena is the result of a thermodynamic state function called entropy (S). Entropy is the measure of the extent to which the energy is dispersed throughout a system, or in other words, it is proportional to the degree of disorder of a...

Entropy

Entropy

The first law of thermodynamics is quantitatively formulated via an equation relating the internal energy of a system, the heat exchanged by it, and the work done on it. A quantitative formulation of the second law of thermodynamics leads to defining a state function, the entropy.
When an ideal gas expands isothermally, the disorder in the gas increases. From the molecular perspective, the gas molecules have more volume to move around in.
Consider an infinitesimal step in the expansion, which...

Entropy Change in Reversible Processes

Entropy Change in Reversible Processes

In the Carnot engine, which achieves the maximum efficiency between two reservoirs of fixed temperatures, the total change in entropy is zero. The observation can be generalized by considering any reversible cyclic process consisting of many Carnot cycles. Thus, it can be stated that the total entropy change of any ideal reversible cycle is zero.
The statement can be further generalized to prove that entropy is a state function. Take a cyclic process between any two points on a p-V diagram.

Entropy and the Second Law of Thermodynamics

Entropy and the Second Law of Thermodynamics

The second law of thermodynamics can be stated quantitatively using the concept of entropy. Entropy is the measure of disorder of the system.
The relation between entropy and disorder can be illustrated with the example of the phase change of ice to water. In ice, the molecules are located at specific sites giving a solid state, whereas, in a liquid form, these molecules are much freer to move. The molecular arrangement has therefore become more randomized. Although the change in average...

Entropy and the Second Law of Thermodynamics

Entropy and the Second Law of Thermodynamics

Consider an isolated system in which a hot object is placed in contact with a cold one. This is an irreversible process that eventually leads both objects to reach the same equilibrium temperature. It is crucial to note that the constituents of any substance exhibit increased disorder at higher temperatures. As a cold substance absorbs heat, its constituents become more disordered. The energy transfer from a hotter object to a cooler one increases the system's disorder or randomness. This...

Divergence and Curl of Magnetic Field

Divergence and Curl of Magnetic Field

The magnetic field due to a volume current distribution given by the Biot–Savart Law can be expressed as follows:

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Global research landscape, knowledge structure, and emerging trends in adverse childhood experiences and personality disorders: a bibliometric analysis.

Frontiers in psychiatry·2026

Same author

Stable and High-Throughput Single-Cell Sorting of Food Bacteria Using Spatiotemporal Video-Enhanced Raman Tweezers.

Foods (Basel, Switzerland)·2026

Same author

TDLAS-based distributed monitoring method for multi-component gas leakage in crude oil storage tanks.

Optics express·2026

Same author

Protocol for the "motor-brain development" trial: effects of motor-focused exercise training on brain function and gross motor skills in preschool children.

Frontiers in pediatrics·2026

Same author

Rapid single-cell identification of foodborne pathogens with limited data: A peak-aware Raman attention deep learning model.

Current research in food science·2026

Same author

Comprehensive strategies to defeat Candida auris - challenge and insight: A review.

Medicine·2025

Search research articles

Related Experiment Video

Updated: Mar 28, 2026

Experimental Investigation of Secondary Flow Structures Downstream of a Model Type IV Stent Failure in a 180° Curved Artery Test Section

Experimental Investigation of Secondary Flow Structures Downstream of a Model Type IV Stent Failure in a 180° Curved Artery Test Section

Published on: July 19, 2016

Braid Entropy of Two-Dimensional Turbulence.

Nicolas Francois¹, Hua Xia¹, Horst Punzmann¹

¹Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200, Australia.

Scientific Reports

|December 23, 2015

Summary

Researchers developed a new topological method to measure the entanglement of fluid lines in turbulent flows. This approach quantifies fluid line dynamics using topological length and braid topological entropy, offering insights into turbulence irreversibility.

More Related Videos

Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow

Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow

Published on: February 27, 2016

Magnetically Induced Rotating Rayleigh-Taylor Instability

Magnetically Induced Rotating Rayleigh-Taylor Instability

Published on: March 3, 2017

Related Experiment Videos

Last Updated: Mar 28, 2026

Experimental Investigation of Secondary Flow Structures Downstream of a Model Type IV Stent Failure in a 180° Curved Artery Test Section

Experimental Investigation of Secondary Flow Structures Downstream of a Model Type IV Stent Failure in a 180° Curved Artery Test Section

Published on: July 19, 2016

Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow

Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow

Published on: February 27, 2016

Magnetically Induced Rotating Rayleigh-Taylor Instability

Magnetically Induced Rotating Rayleigh-Taylor Instability

Published on: March 3, 2017

Area of Science:

Fluid dynamics
Turbulence research
Complex systems analysis

Background:

Predicting material transport and dissipation in industrial and natural processes relies on understanding fluid line dynamics.
Experimental measurement of fluid line deformation in turbulent flows is challenging due to reliance on inaccessible multi-particle data.

Purpose of the Study:

To introduce a novel topological approach for characterizing fluid line dynamics in turbulent flows.
To establish a method for quantifying material fluid line evolution using Lagrangian trajectory data.

Main Methods:

Laboratory measurements in two-dimensional turbulence.
Characterization of Lagrangian trajectory braids using entanglement measures.
Derivation of topological length (NE) and braid topological entropy (SBraid).

Main Results:

Topological length (NE) of material fluid lines grows exponentially over time.
Braid topological entropy (SBraid) increases with the square root of turbulent kinetic energy.
Probability distribution of NE exhibits positive skewness and exponential tails at long times.

Conclusions:

SBraid provides a measure of turbulence irreversibility based on minimal principles.
The topological approach offers an alternative to multi-particle data for studying fluid dynamics.
This method allows for quantitative analysis using sparse Lagrangian data.