Related Experiment Video
Updated: Mar 19, 2026
08:19
Induction of Microstreaming by Nonspherical Bubble Oscillations in an Acoustic Levitation System
Published on: May 9, 2021
2.8K
River bedform inception by flow unsteadiness: A modal and nonmodal analysis
Alice Caruso1, Riccardo Vesipa1, Carlo Camporeale1
1Department of Environmental, Land and Infrastructure Engineering, Politecnico di Torino, Corso Duca Abruzzi 24, 10129 Turin, Italy.
Physical Review. E
|June 15, 2016
Summary
Flow unsteadiness significantly influences river bedform development, moving beyond constant flow assumptions. This study analyzes periodic flow effects on dune and antidune formation using a validated 1D model.
Area of Science:
- * Fluid Dynamics and Sediment Transport
- * Geomorphology and River Engineering
Background:
- * River bedforms like dunes and antidunes result from stream-sediment interface instabilities.
- * Understanding bedform dynamics is crucial for engineering and environmental applications.
- * Previous studies often assumed constant flow rates, neglecting natural flow variability.
Purpose of the Study:
- * To investigate the impact of periodic flow unsteadiness on river bedform inception.
- * To extend existing models by incorporating flow variability in bedform dynamics.
Main Methods:
- * Utilized a validated one-dimensional (1D) model.
- * Coupled Dressler's equations with a refined mechanistic sediment transport formulation.
- * Employed modal and nonmodal analyses to study asymptotic and transient dynamics.
Main Results:
- * Periodic flow unsteadiness affects the initiation and development of river bedforms.
- * Model analysis reveals insights into both short-term (transient) and long-term (asymptotic) bedform evolution under unsteady flow.
Conclusions:
- * Flow unsteadiness is a critical factor in river bedform formation, not just constant flow.
- * The 1D model provides a valuable tool for studying bedform dynamics under realistic, variable flow conditions.
Related Concept Videos
01:24Rapidly Varying Flow
613
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...
613
01:23Introduction to Types of Flows
2.1K
Fluid flows are categorized by dimensionality and behavior, with one-dimensional flow being the simplest form, where properties like velocity and pressure change only along a single axis. Water moving through straight pipes exemplifies this flow type, as variations in other directions are minimal. One-dimensional analysis helps simplify understanding such flows, focusing solely on changes along the pipe's length.
Two-dimensional flow involves changes in both length and height, as seen in...
Two-dimensional flow involves changes in both length and height, as seen in...
2.1K
01:30Typical Model Studies
677
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.
677
01:29Gradually Varying Flow
513
Gradually varying flow (GVF) in open channels describes situations where water depth changes slowly along the channel due to factors like non-uniform bed slope, channel shape variations, or obstructions. This flow type occurs when the depth adjusts gradually to balance gravitational forces, shear forces, and energy requirements, resulting in a low rate of depth change.Characteristics of Gradually Varying FlowGVF is commonly observed in natural streams, rivers, and canals, where flow depth...
513
01:23Plane Potential Flows
1.0K
Plane potential flows simplify fluid motion by assuming the fluid to be irrotational and incompressible. These characteristics allow these flows to be described by a velocity potential function, ϕ, representing the flow speed in a given direction, and a stream function, ψ, that visualizes the flow path, both governed by Laplace's equation. These parameters help in estimating flow patterns, velocity distributions, and pressure fields around various hydraulic structures.
Uniform...
Uniform...
1.0K
01:27Steady Flow of a Fluid Stream
830
Consider a control volume, such as a pipe with solid boundaries, through which fluid flows and changes direction due to the impulse exerted by the resulting force from the pipe walls. In steady flow, the mass of fluid entering the control volume at a given time, t, with velocity v1, is equal to the mass leaving after infinitesimal time dt, with velocity v2.
During this process, the momentum of the fluid within the control volume remains constant over the time interval dt. By applying the...
During this process, the momentum of the fluid within the control volume remains constant over the time interval dt. By applying the...
830