Research

The major algorithmic challenge to simulate incompressible fluid flows is the non-availability of a separate transport equation for pressure. To overcome this, we develop efficient methods to simulate single- and two-phase incompressible flows, based on the recently proposed artificial compressibility methods. The in-house solver is rigorously validated against laminar and DNS of turbulent flows. Incorporation of high-order accurate compact schemes and large eddy simulation (LES) are in progress. To enable simulations of large-scale turbulent flows, our solver is parallelized for multiCPU and multiGPU compute architectures. Our group members regularly attend NSM open hackathons to learn GPU computing and upgrade our solver.

Surface coatings in the form of roughness patterns, hairs, feathers and other filamentous structures are ubiquitous in nature. The superior performance of such complex multiscale surfaces, when compared to their smooth counterparts, has motivated the development of biomimetic passive flow control strategies. Due to the multiscale characteristics of such surfaces, conducting experiments or performing direct numerical simulations is highly challenging. In order to shed light on the fluid dynamic mechanisms underlying the interaction between these complex surfaces and the surrounding flow, we derive accurate homogenized models from first principles and develop robust computational frameworks. Our models developed for rough and porous surfaces are thoroughly validated with geometry-resolved simulations. Extension of our model to poroelastic coatings and incorporation of inertial effects are in progress.

Insect flight can't be explained by conventional steady state aerodynamics theories. They largely rely on unsteady aerodynamic principles to augment the lift forces generated on their rapidly flapping wings. Several CFD studies and experiments conducted over the dynamically scaled robotic models of small insects have significantly improved our understanding of insect flight. By employing in-house codes and commercial CFD packages, we investigate the spatiotemporal dynamics of vorticity associated with flapping rigid- and flexible-wings.