Related Experiment Video
Updated: Jun 14, 2026
11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Traveling shock front in quasi-two-dimensional granular flows
Guoqi Hu1, Yinchang Li, Meiying Hou
1Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing.
Summary
Granular shocks exhibit unique temperature profiles explained by kinetic theory. Unlike ordinary fluids, their shock width increases with inflow rate, a novel finding in granular physics.
Area of Science:
- Physics
- Granular Mechanics
- Fluid Dynamics
Background:
- Granular shock fronts share density profile similarities with supersonic fluids.
- However, their temperature profiles diverge significantly from conventional shock phenomena.
Purpose of the Study:
- To investigate the density and temperature profiles of traveling granular shocks.
- To develop a theoretical model for granular shock temperature.
- To explore the relationship between granular shock width and inflow rate.
Main Methods:
- Experimental generation of granular shocks using metal spheres in a quasi-two-dimensional channel.
- Analysis of density and temperature profiles within the shock front.
- Application of a simple kinetic theory focusing on energy transfer between flow directions.
Main Results:
- A kinetic theory successfully accounts for the granular shock temperature profile.
- Energy transfer from mean flow to transverse directions is key.
- Granular shock width was observed to increase with the inflow rate, contrary to expectations.
Conclusions:
- The study provides a theoretical framework for understanding granular shock temperature.
- The observed increase in shock width with inflow rate presents a new characteristic of granular shocks.
- Findings challenge previous assumptions based on ordinary fluid shocks.
More Related Videos
Related Concept Videos
01:16Shock Waves
While deriving the Doppler formula for the observed frequency of a sound wave, it is assumed that the speed of sound in the medium is greater than the source's speed through it. When this condition is breached, a shock wave occurs.
When the source's speed approaches the speed of sound, constructive interference between successive wavefronts emitted by the source occurs immediately behind it. Initially, scientists believed that this constructive interference would result in such high pressures...
When the source's speed approaches the speed of sound, constructive interference between successive wavefronts emitted by the source occurs immediately behind it. Initially, scientists believed that this constructive interference would result in such high pressures...
01:17Steady, Laminar Flow Between Parallel Plates
Understanding steady, laminar flow between parallel plates is essential for analyzing and designing flow in narrow rectangular channels, commonly found in various water conveyance and drainage systems. The Navier-Stokes equations govern fluid motion and are generally challenging to solve due to their nonlinearity. However, simplifications are possible in certain cases, like the steady laminar flow between parallel plates. For this scenario, we assume steady, incompressible, laminar flow.
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...
01:23Plane Potential Flows
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 Flow
Uniform flow...
Uniform Flow
Uniform flow...
01:07Laminar and Turbulent Flow
Fluid dynamics is the study of fluids in motion. Velocity vectors are often used to illustrate fluid motion in applications like meteorology. For example, wind—the fluid motion of air in the atmosphere—can be represented by vectors indicating the speed and direction of the wind at any given point on a map. Another method for representing fluid motion is a streamline. A streamline represents the path of a small volume of fluid as it flows. When the flow pattern changes with time, the streamlines...
01:24Turbulent Flow
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 spots,...