Related Experiment Video
Updated: Jun 23, 2025

Forming, Confining, and Observing Microtubule-Based Active Nematics
Published on: January 13, 2023
Extremely persistent dense active fluids
Grzegorz Szamel1, Elijah Flenner1
1Department of Chemistry, Colorado State University, Fort Collins, CO, USA. grzegorz.szamel@colostate.edu.
Abstract:
We study the dynamics of dense three-dimensional systems of active particles for large persistence times τp at constant average self-propulsion force f. These systems are fluid counterparts of previously investigated extremely persistent systems, which in the large persistence time limit relax only on the time scale of τp. We find that many dynamic properties of the systems we study, such as the mean-squared velocity, the self-intermediate scattering function, and the shear-stress correlation function, become τp-independent in the large persistence time limit. In addition, the large τp limits of many dynamic properties, such as the mean-square velocity and the relaxation times of the scattering function, and the shear-stress correlation function, depend on f as power laws with non-trivial exponents. We conjecture that these systems constitute a new class of extremely persistent active systems.
Related Concept Videos
Viscosity
The SI unit of viscosity is...
Types of Fluids
In contrast, non-Newtonian fluids do not follow Newton's law of viscosity, and...
Pleural Effusion I: Introduction
There are two main types of pleural effusion: transudative and exudative. They are differentiated using Light's...
Characteristics of Fluids
Fluids, which include both liquids and gases, are substances that deform continuously under shearing stress. For example, water and oil are liquids with molecules that can...
Surface Tension, Capillary Action, and Viscosity
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
Colloids and Suspensions

