Related Experiment Video
Updated: Mar 24, 2026

11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
9.1K
Variational principle for nonlinear wave propagation in dissipative systems
Hans Dierckx1, Henri Verschelde1
1Department of Mathematical Physics and Astronomy, Ghent University, 9000 Ghent, Belgium.
Physical Review. E
|March 18, 2016
Summary
Nonlinear wave fronts in natural systems can be described by a gradient system, simplifying their dynamics. This applies even when the original equations are not gradient systems, using volume and surface area as a potential.
Area of Science:
- Physics
- Applied Mathematics
- Complex Systems
Background:
- Many natural systems exhibit dynamics governed by nonlinear waves.
- Understanding wave front propagation is crucial in diverse scientific fields.
Purpose of the Study:
- To demonstrate that nonlinear wave front dynamics in extended systems with positive surface tension can be formulated as a gradient system.
- To identify the variational potential governing this asymptotic behavior.
Main Methods:
- Analysis of nonlinear wave front propagation in extended systems.
- Formulation of asymptotic dynamics as a gradient system.
- Identification of the variational potential based on geometric properties.
Main Results:
- The asymptotic dynamics of wave fronts with positive surface tension can be consistently described by a gradient system.
- The variational potential is a linear combination of the wave front's occupied volume and surface area.
- This potential changes monotonically over time, indicating a predictable evolution.
Conclusions:
- The gradient system formulation provides a powerful simplification for studying nonlinear wave front dynamics.
- This approach is applicable even when the underlying field equations lack a gradient structure.
- The identified variational potential offers insights into the fundamental drivers of wave front evolution.
More Related Videos
Related Concept Videos
Velocity and Acceleration of a Wave
5.1K
A wave propagates through a medium with a constant speed, known as a wave velocity. It is different from the speed of the particles of the medium, which is not constant. In addition, the velocity of the medium is perpendicular to the velocity of the wave. The variable speed of the particles of the medium implies that there must be acceleration associated with it.
The velocity of the particles can be obtained by taking the partial derivative of the position equation with respect to time....
The velocity of the particles can be obtained by taking the partial derivative of the position equation with respect to time....
5.1K
Linear Approximation in Frequency Domain
424
Linear systems are characterized by two main properties: superposition and homogeneity. Superposition allows the response to multiple inputs to be the sum of the responses to each individual input. Homogeneity ensures that scaling an input by a scalar results in the response being scaled by the same scalar.
In contrast, nonlinear systems do not inherently possess these properties. However, for small deviations around an operating point, a nonlinear system can often be approximated as linear....
In contrast, nonlinear systems do not inherently possess these properties. However, for small deviations around an operating point, a nonlinear system can often be approximated as linear....
424
Propagation of Waves
3.2K
When a wave propagates from one medium to another, part of it may get reflected in the first medium, and part of it may get transmitted to the second medium. In such a case, the interface of the two mediums can be considered as a boundary that is neither fixed nor free.
Consider a scenario where a wave propagates from a string of low linear mass density to a string of high linear mass density. In such a case, the reflected wave is out of phase with respect to the incident wave, however the...
Consider a scenario where a wave propagates from a string of low linear mass density to a string of high linear mass density. In such a case, the reflected wave is out of phase with respect to the incident wave, however the...
3.2K
Types of Damping
8.0K
If the amount of damping in a system is gradually increased, the period and frequency start to become affected because damping opposes, and hence slows, the back and forth motion (the net force is smaller in both directions). If there is a very large amount of damping, the system does not even oscillate; instead, it slowly moves toward equilibrium. In brief, an overdamped system moves slowly towards equilibrium, whereas an underdamped system moves quickly to equilibrium but will oscillate about...
8.0K
Damped Oscillations
7.5K
In the real world, oscillations seldom follow true simple harmonic motion. A system that continues its motion indefinitely without losing its amplitude is termed undamped. However, friction of some sort usually dampens the motion, so it fades away or needs more force to continue. For example, a guitar string stops oscillating a few seconds after being plucked. Similarly, one must continually push a swing to keep a child swinging on a playground.
Although friction and other non-conservative...
Although friction and other non-conservative...
7.5K
Traveling Waves: Lossless Lines
513
The provided content explores the behavior of traveling waves on single-phase lossless transmission lines. It begins with a single-phase two-wire lossless transmission line of length Δx, characterized by a loop inductance LH/m and a line-to-line capacitance C F/m. These parameters result in a series inductance LΔx and a shunt capacitance CΔx.
513

