Related Experiment Video
Updated: Jul 19, 2026
10:53
Simultaneous Measurement of Turbulence and Particle Kinematics Using Flow Imaging Techniques
Published on: March 12, 2019
Periodic sedimentation in a Stokesian fluid
Sunghwan Jung1, S E Spagnolie, K Parikh
1Applied Mathematics Laboratory, Courant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New York, New York 10012, USA.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|October 10, 2006
Summary
Two nonspherical particles in fluid exhibit synchronized "tumbling orbits" during sedimentation. This motion involves in-phase rotation, modulated speeds, and changing distances, observed across various body shapes.
Area of Science:
- Fluid dynamics
- Non-Newtonian fluid mechanics
- Particle dynamics
Background:
- Sedimentation of particles in fluids is a fundamental phenomenon in fluid dynamics.
- The behavior of nonspherical particles can deviate significantly from spherical particles due to complex hydrodynamic interactions.
- Understanding particle-particle interactions is crucial for predicting macroscopic behaviors in suspensions and multiphase flows.
Purpose of the Study:
- To investigate the sedimentation dynamics of two identical, nonspherical particles in a Stokesian fluid.
- To identify and characterize novel orbital behaviors and their underlying mechanisms.
- To determine the influence of particle shape on these dynamic interactions.
Main Methods:
- Combined experimental and numerical simulation approaches were employed.
- Experiments utilized controlled setups to observe particle sedimentation.
- Numerical simulations were performed using Stokesian dynamics to model fluid-particle interactions.
Main Results:
- Periodic orbits, termed "tumbling orbits," were discovered for sedimenting nonspherical particles.
- These orbits are characterized by mutually induced in-phase rotational motion.
- The tumbling orbits exhibit periodic modulations in sedimentation speed and inter-particle separation distance.
- This phenomenon was observed across a broad range of investigated body shapes.
Conclusions:
- Nonspherical particle interactions in Stokesian fluids can lead to complex, synchronized dynamics beyond simple settling.
- "Tumbling orbits" represent a significant finding in the study of particle sedimentation, highlighting the role of shape.
- The observed phenomena have implications for understanding mixing, aggregation, and transport in various multiphase systems.
Related Concept Videos
01:20Stokes' Law
Viscous forces, like friction, are intermolecular forces that resist the relative motion of molecules over each other. When a solid body moves through a liquid, viscous forces drag it in the opposite direction. The force's magnitude depends on the solid's shape and size, as well as its speed and the liquid's coefficient of viscosity, density and temperature.
The expression for the force on a solid spherical object in a fluid is called Stokes' law. Stokes' law is valid only for low Reynolds...
The expression for the force on a solid spherical object in a fluid is called Stokes' law. Stokes' law is valid only for low Reynolds...
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.
01:28Navier–Stokes Equations
For incompressible Newtonian fluids, where density remains constant, stresses show a linear relationship with the deformation rate, defined by normal and shear stresses. Normal stresses depend on the pressure exerted on the fluid and the rate of deformation in specific directions, which determines how fluid flows under varying pressures. Shear stresses, on the other hand, act tangentially across fluid layers. They explain how adjacent fluid layers slide relative to one another, connecting...
01:18Newtonian Fluid: Problem Solving
Newtonian fluids exhibit a constant viscosity, meaning their shear stress and shear strain rate are directly proportional. This property ensures a predictable and stable response to applied forces, maintaining a linear relationship between force and flow. Examples include water, air, and light oils, consistently demonstrating this proportional behavior regardless of external conditions.
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
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...
01:23Steady, Laminar Flow in Circular Tubes
Hagen-Poiseuille flow describes a viscous fluid's steady, incompressible flow through a cylindrical tube with a constant radius R. This flow profile is often applied to understand fluid transport in narrow channels, such as capillaries. It serves as a foundational example of laminar flow. In this model, cylindrical coordinates (r,θ,z) are used to describe the radial (r), angular (θ), and axial (z) dimensions within the tube. For Hagen-Poiseuille flow, the velocity profile is purely axial,...