Related Experiment Video
Updated: Jun 23, 2025
11:00
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
11.6K
Random walk model for dual cascades in wave turbulence
1Courant Institute of Mathematical Sciences, New York University, New York, New York 10012, USA.
Physical Review. E
|June 22, 2024
Summary
Hydrodynamic and wave turbulence exhibit distinct dual cascades. Wave turbulence shows large flux fluctuations, explained by a random walk model, suggesting chance rather than irreversible dynamics drives these spectral fluxes.
Area of Science:
- Physics
- Fluid Dynamics
- Nonlinear Systems
Background:
- Dual cascades, involving two conserved quadratic quantities, are observed in 2D hydrodynamic turbulence and wave turbulence.
- Wave turbulence examples include surface waves and nonlinear Schrödinger equations with cubic nonlinearity.
Purpose of the Study:
- To compare the physical nature of dual cascades in 2D hydrodynamic turbulence and 1D wave turbulence.
- To investigate the reasons behind the stark differences observed in their spectral fluxes and fluctuations.
Main Methods:
- Numerical simulations of forced-dissipative equilibrium for both 2D hydrodynamic turbulence and a 1D wave system.
- Comparison of energy spectra within the inertial range and analysis of temporal flux fluctuations.
- Formulation and testing of a random walk model for wave turbulence dual cascades.
Main Results:
- Significant differences were found in the spectra and temporal flux fluctuations between hydrodynamic and wave turbulence.
- Wave turbulence exhibited much larger flux fluctuations, including sign reversals, absent in hydrodynamic turbulence.
- A random walk model successfully replicated observed turbulent spectra and explained large flux fluctuations in wave turbulence.
Conclusions:
- The dual cascade in wave turbulence does not necessitate an irreversible dynamical mechanism.
- Observed spectral fluxes in wave turbulence can arise from random chance, as evidenced by the random walk model.
- Nonlinear diffusion models fail to explain the spectral shapes observed in wave turbulence.
More Related Videos
Related Concept Videos
01:24Rapidly Varying Flow
57
Rapidly varying flow (RVF) in open channels is characterized by abrupt changes in flow depth over a short distance, with the rate of depth change relative to distance often approaching unity. These flows are inherently complex due to their transient and multi-dimensional nature, making exact analysis difficult. However, approximate solutions using simplified models provide valuable insights into their behavior.Key Features of Rapidly Varying FlowRVF is commonly observed in scenarios involving...
57
01:30Typical Model Studies
354
Fluid mechanics model studies often utilize scaled-down systems to predict fluid behavior in full-scale environments, such as river flows, dam spillways, and structures interacting with open surfaces. Maintaining Froude number similarity in river models is crucial, as it replicates surface flow features like wave patterns and velocities.
354
01:21Design Example: Creating a Hydraulic Model of a Dam Spillway
158
Scaled hydraulic models of dam spillways provide a practical way to replicate and study the intricate flow dynamics of these structures. Often built to a 1:15 ratio, these models allow for observing critical water behavior, such as velocity distribution, flow patterns, and energy dissipation.
158
01:27Traveling Waves: Lossless Lines
136
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.
136
01:24Turbulent Flow
167
Turbulent flow is characterized by unpredictable fluctuations in velocity and pressure, which result in a chaotic fluid movement distinct from the orderly patterns of laminar flow. While laminar flow is governed by smooth, parallel layers with minimal mixing, turbulent flow exhibits highly irregular, three-dimensional patterns. This behavior arises due to instabilities in the fluid's velocity profile, and amplifies as the flow velocity increases. Minor disturbances, known as turbulent...
167
01:07Damped Oscillations
5.7K
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...
5.7K