Turbulence-Suppressing Polymers

Adding just a little polymer to a pipe flow speeds it up by reducing drag near the wall. But the effects on turbulence away from the wall have been harder to suss out. A new experiment shows that added polymers suppress eddy formation in the flow and reduce how much energy is lost to friction and, ultimately, heat. In particular, the researchers found that polymer stress helped stabilize shear layers in the flow and prevent them from destabilizing into more turbulent flow. (Image credit: S. Wilkinson; research credit: Y. Zhang et al.; via APS)

#dissipation #elasticTurbulence #fluidDynamics #instability #physics #polymerEffects #science #turbulence #viscoelasticity

Active nematic fluids borrow their ingredients from biology. Using long, rigid microtubules and kinesin motor proteins capable of cross-linking between and “walking” along tubules, researchers create these complex flow patterns. Here, a team took the system a step further by seeding the flow with a hydrogel that turns into a polymer when exposed to light. Then, by shining light patterns on the flow, the scientists can create rigid or flexible structures inside the active fluid. In this case, they show off some of the neat flow patterns they can create. (Video and image credit: G. Pau et al.)

https://fyfluiddynamics.com/2024/06/growing-hydrogels-in-an-active-fluid/

#2024gosm #activeMatter #activeNematicFluid #fluidDynamics #hydrogel #physics #polymerEffects #science