Related Experiment Video
Updated: Jun 21, 2026
10:32
Image-based Lagrangian Particle Tracking in Bed-load Experiments
Published on: July 20, 2017
Subordinated Brownian motion model for sediment transport
Vamsi Ganti1, Arvind Singh, Paola Passalacqua
1Department of Civil Engineering, St. Anthony Falls Laboratory and National Center for Earth-Surface Dynamics, University of Minnesota, Minnesota, USA.
Summary
We introduce fractional Laplace motion, a new stochastic model for sediment transport. This model accurately reproduces the multiscale statistics of sediment transport rates observed in experiments.
Area of Science:
- Geosciences
- Physics
- Hydrology
Background:
- Stochastic models like Brownian motion are used for sediment transport.
- Existing models fail to reproduce non-Gaussian probability density functions (PDFs) of sediment transport rates.
- Observed PDFs depend on time scale, a factor not previously modeled.
Purpose of the Study:
- To propose a novel stochastic model for sediment transport.
- To account for the time-scale dependence of sediment transport statistics.
- To model the random nature of particle motion duration.
Main Methods:
- Extension of Brownian motion to fractional Laplace motion.
- Incorporation of random motion time into the model.
- Validation using large-scale laboratory experiments.
Main Results:
- The proposed fractional Laplace motion model reproduces observed multiscale statistics.
- The model accounts for the dependence of sediment transport PDFs on time scale.
- Demonstrated ability to capture complex sediment transport dynamics.
Conclusions:
- Fractional Laplace motion offers a more accurate representation of sediment transport.
- This model advances our understanding of non-Gaussian sediment transport dynamics.
- The findings have implications for hydrological and geoscientific modeling.
Related Concept Videos
01:09Theories of Dissolution: The Danckwerts' Model and Interfacial Barrier Model
Various dissolution theories provide insight into the factors that influence the dissolution rate. Danckwerts' Model suggests that turbulence, rather than a stagnant layer, characterizes the dissolution medium at the solid-liquid interface. In this model, the agitated solvent contains macroscopic packets that move to the interface via eddy currents, facilitating the absorption and delivery of the drug to the bulk solution. The regular replenishment of solvent packets maintains the concentration...
01:07Damped Oscillations
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...
01:18Boundary Layer Characteristics
When a fluid encounters a solid surface, a boundary layer forms due to the interaction between the fluid's motion and the stationary surface. This phenomenon is characterized by a thin region adjacent to the surface where viscous forces dominate, influencing the fluid's velocity profile. The development of the boundary layer begins at the leading edge of the surface and evolves as the fluid moves downstream.As the fluid flows over the surface, friction between the fluid and the wall slows down...
01:10First Law: Particles in One-dimensional Equilibrium
Newton's first law of motion states that a body at rest remains at rest, or if in motion, remains in motion at constant velocity, unless acted on by a net external force. It also states that there must be a cause for any change in velocity (a change in either magnitude or direction) to occur. This cause is a net external force. For example, consider what happens to an object sliding along a rough horizontal surface. The object quickly grinds to a halt, due to the net force of friction. If we...
01:30Typical Model Studies
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.
01:22Couette Flow
Couette flow represents the flow of fluid between two parallel plates, with one plate fixed and the other moving with a constant velocity. This configuration allows for a simplified analysis using the Navier-Stokes equations, which govern fluid motion under conditions of viscosity and incompressibility. For Couette flow, the assumptions include a steady, laminar, incompressible flow with a zero-pressure gradient in the flow direction. This flow type is beneficial for understanding shear-driven...