Abstract
Many liquids in the modern world possess both elastic and viscous properties (e.g. paints, saliva and DNA suspensions among many others polymers). Understanding their behaviour is paramount in many industrial processes where turbulence is commonplace but may be highly undesirable (e.g. pharmaceutical, chemical, and plastic). Little is known about how and why this viscoelastic turbulence occurs, mainly due to the complexity and variety of the mathematical models used to describe it. In particular, it has only recently been realised that there may be three distinct types: a polymer-adjusted Newtonian turbulence (NT) which predominantly exists due to inertial effects, Elastic turbulence (ET) which exists in the absence of inertia and is entirely driven by the elasticity, and a third form called Elasto-inertial turbulence (EIT) which requires a balance of inertia and elasticity to exist. Many questions exist about these two forms of viscoelastic turbulence: in particular, whether they are dynamically connected, what triggers them and how EIT interacts with the presence of Newtonian turbulence at low levels of elasticity. In this talk, I will attempt to review recent work seeking some answers largely stimulated by a recently-discovered viscoelastic centre mode instability (Garg et al. Phys. Rev. Lett., 121, 024502, 2018) and a newly-discovered `polymer diffusive instability’ (Beneitez et al. Phys. Rev. Fluids 8, L101901, 2023).
About the Speaker
Miguel Beneitez is a Lecturer (Assist. Prof.) in the Department of Mechanical and Aerospace Engineering at the University of Manchester (UK), where he is also affiliated with the Manchester Centre for Nonlinear Dynamics. He received his PhD in Engineering Mechanics from KTH Royal Institute of Technology (Sweden) in 2021 for which he was awarded a “Da Vinci Competition” medal. Before joining Manchester, Miguel held a postdoctoral appointment at Department of Applied Mathematics and Theoretical Physics (DAMTP), University of Cambridge (UK), where he also was a Junior Research Fellow in Applied Mathematics at Christ’s College. He also held a brief postdoctoral appointment at KTH Royal Institute of Technology (Sweden). His research interests lie in the intersection between applied mathematics, fluid dynamics (encompassing both Newtonian and complex fluids), and machine learning. Miguel’s research is motivated by challenges in engineering, medicine and sustainability.
Host: Professor Ricardo Constante Amores