MechE Colloquium: Vortex ring collisions and fluctuation forces in turbulence

Thumbnail

Event details

Date 01.04.2025
Hour 12:0013:00
Speaker Prof. Rodolfo OSTILLA MONICOMechanical Engineering and Industrial DesignUniversity of Cádiz
Location Online
Category Conferences - Seminars
Event Language English
Abstract: In the first half of the talk I will discuss numerical simulations of vortex ring collisions in an attempt to understand the rapid formation of very fine scale turbulence (or ’smoke’) from relatively smooth initial conditions. Different perturbations to the ring vortex are added, and their effect on the generation and amplification of turbulence is quantified. The underlying dynamics of the vortex core is analyzed. The presence of Crow and elliptic instabilities is used to explain the different dynamics: either turbulent reconnection or cloud formation. The asymptotic behaviour of the collision behaviour is analyzed, and a link to the turbulent energy cascade is revealed. In the second half of the talk I will discuss the discovery of a surprising fluctuation-induced force between two plates immersed in homogeneous isotropic turbulence using Direct Numerical Simulations. The force is a non-monotonic function of plate separation. The mechanism of force generation reveals an intriguing analogy with fluctuation-induced forces: energy in the fluid is localised in regions of high vorticity, or "worms", which have a characteristic length scale. The magnitude of the force depends on the packing of worms inside the plates, with the maximal force attained when the plate separation is comparable to the characteristic worm length. A key implication of our study is that the length scale-dependent partition of energy in an active or non-equilibrium system determines force generation.



Biography: Rodolfo Ostilla Mónico is an Emergia Researcher in Fluid Mechanics at the University of Cádiz. After graduating in Aerospace Engineering at the University of Seville in 2010, he obtained a doctoral degree at the Physics of Fluids group at the University of Twente in 2015. He then spent some years in the United States, first as a postdoctoral researcher at Harvard University and later as an assistant professor at the University of Houston, before joining the University of Cadiz in 2022. His research is mainly in the field of computational fluid mechanics, with particular interest in numerical simulations of convective flows, vortex ring collisions and more generally, of turbulent systems.

Practical information

  • General public
  • Free

Organizer

Tags

MechE Colloquium: Vortex ring collisions and fluctuation forces in turbulence

Share