Veranstaltung
Inertial active suspensions: Stability and Turbulence| Titel der Veranstaltung | Inertial active suspensions: Stability and Turbulence |
| Reihe | LMP Seminar |
| Veranstalter | Physik lebender Materie |
| Referent/in | Dr. Navdeep Rana |
| Einrichtung Referent/in | Dept. of Living Matter Physics, MPI for Dynamics and Self-Organization, Göttingen |
| Veranstaltungsart | Seminar |
| Kategorie | Forschung |
| Anmeldung erforderlich | Nein |
| Beschreibung | Suspensions of self-propelled particles, for example, bacteria, show spectacular collective behaviour. The Reynolds number, which measures the relative strength of inertial and viscous forces, characterizes such suspensions. In the low Reynolds number limit, where viscosity dominates over inertia, a uniform aligned state of swimmers is unstable to small perturbations. This instability lies at the heart of widely observed active turbulence. In this seminar, I will talk about swimmer suspensions at Reynolds number of order unity, where viscous and inertial forces are comparable. I will show how the dimensionless number R, a combination of suspension inertia, swimmer motility, and active stress, determines the stability of orientational order against small perturbations in extensile suspensions. At small R, perturbations grow at a rate linear to the magnitude of their wavevector, q. The growth is slower for an intermediate range of R, with a rate proportional to q2. Finally, at large R, the flock becomes stable. Direct numerical simulations reveal that Malthusian suspensions show a transition from isotropic hedgehog-defect turbulence to phase turbulence as we increase R. On the other hand, Dense suspensions show a transition from vortex-defect turbulence to complete orientational order. |
| Zeit | Beginn: 08.02.2022, 14:00 Uhr Ende: 08.02.2022 , 15:30 Uhr |
| Ort |
Max-Planck-Institut für Dynamik und Selbstorganisation (MPIDS) (Am Faßberg 17) Video conference at www.zoom.us Meeting ID: 997 1155 2453 Passcode: 771001 |
| Kontakt |
Prof. Dr. Ramin Golestanian golestanian-office@ds.mpg.de |