Abstract : This seminar will focus on the effects of viscoelasticity on passive fluid flows and active living system. It is well known that viscoelasticity affects the fluid flows significantly, in the turbulent flow they lead to dissipation reduction. In the first part of the seminar, the effects of polymer additives in two-dimensional homogeneous, isotropic turbulence will be discussed. This work focuses on studying the statistical properties using direct numerical simulations. The kinetics of the polymers is introduced using constitutive equations for viscoelastic fluids with finitely extensible non-linear elastic dumbbells with Peterlin's closure (FENE-P). Our study reveals that the polymers have a significant effect on multiple scales of the turbulent flow affecting some of the physical quantities and their intermittent properties. The second part will be focused on the mechanical regulation of shape deformation by matrix viscoelasticity in breast tissues. The shape change is one of the phenomena seen in cancerous tissue and the physical mechanism that allows this process to take place has not been clear. The synthetic extracellular matrix (ECM) are typically almost purely elastic. In contrast, the physiological ECM in various tissues, such as brain, liver, adipose tissue, and coagulated bone marrow, etc. are all viscoelastic. Most of the studies to date have focussed largely on elastic properties of ECM. Recently synthetic ECMs have been developed which closely mimic the natural viscoelastic ECMs. This study further looks into the role of such mechanical properties in inducing the malignant phenotype in normal mammary epithelium MCF10A cell line. Based on these experimental findings a mathematical model to capture the qualitative results have been proposed. This is the first mechanical model to capture the epithelial to mesenchymal transition by changing the viscoelastic properties of ECM.
Bio : Currently, Anupam Gupta is a postdoctoral fellow in the group of Prof. L. Mahadevan, working on mathematical modeling of complex system and collective behavior at School of Engineering and Science, Harvard University, USA. Before joining Mahadevan's group, he was in Toulouse, France and worked on elastic turbulence and inertial migration of particles in microchannel flow. He joined the University of Rome for his first postdoc and developed a hybrid Lattice-Boltzmann Code and finite difference code to work on the effects of viscoelasticity and thermocapillary in Droplet dynamics and breakup. He did his PhD with Prof. Rahul Pandit at IISc, Bangalore in 2014. In the first part of his PhD he developed a pseudo-spectral code to model viscoelastic fluids and in the second part of his PhD he developed Lagrangian tracking code to study the particle transport in turbulent flow.
This seminar is compulsory for students registered for course CL 702 or CL 704.