Indian Institute of Science
Aeroservoelasticity Laboratory
Research overview
We have worked on the following problems in the last few years.
Aeroelasticity
Vorticity and elastodynamics in flapping wing propulsion
We know that fluttering flags are associated with drag and a flexible flapping wing is associated with thrust. both these phenomena are problems in fluid-elasticity. the former is an instability while the latter is a fluid-elastic response to muscular or extraneous excitation. we seek to understand the interplay of fluid forces and elastic deformation---the creation and transport of vorticity as a function of elastic deformation---that differentiates one from the other. the numerical tools used are unsteady flow models of potential and incompressible viscous fluid coupled with a Bernoulli-Euler model of a linearly elastic foil.
Shock-boundary layer interactions in the transonic flutter of a wing
Transonic flutter is a concern in aircraft. the transonic dip in the flutter speed, relative to that of subsonic flutter, is a consequence of compressibility, the wake vortex, shock displacement, and shock-boundary layer interaction. we quantitatively characterize these effects and also examine the influence of aeroelastic parameters such as mass ratio, radius of gyration, offset of the center of mass relative to the elastic axis, and others, on transonic flutter. both Euler and Reynolds averaged Navier-Stokes 2D flow solvers are coupled to two-degree of freedom oscillator models of a wing section. 3D Euler solvers coupled to modal structural dynamic models of generic wing geometries investigate transonic flutter over a finite span wing.
Flutter prediction from flight test data
Flutter prediction is a necessity for clearance and certification of airworthiness of aircraft. flight fluttering testing is done away from the flutter boundary in the off-critical flight regime. predicting the flutter speed from the off-flutter measured parameters for each Mach number is what flutter prediction is all about. we are working with flutter margin, arma, and arma coupled with flutter margin based techniques for predicting flutter. the data used for flutter prediction are from flight testing of a flexible aircraft.
Mechanics of polymers
Molecular basis for stress, strain, and viscoelasticity in polymers
The stress developed in a polymer under time-dependent strain is a complex function of its structure and externally set parameters such as temperature, density, strain rate, and chain length. we are studying the correlation of the micro-structure of a polymer and the anisotropic stress developed in it under time-varying strain using molecular dynamic simulation. we also examine the role of bonded and non-bonded interactions to the uniaxial anisotropic stress. the influence of ferrite particles and magnetic field on the polymer behavior is also investigated.
Hemodynamic-vascular mechanics
Fluid-structure interactions in aneurysms
Fluid-structure interactions in abdominal aortic aneurysms and celebral aneurysms.