In this page you shall find links to movies I have found useful in my research. Most of them come with a short description and links to the relevant paper(s).
This is a simulation of rigid spheres in a plane Couette flow. The suspension is a non-Newtonian fluid, its viscosity increases with the imposed strain rate (it shear thickens). Here the novelty is that we confine the system in a thin channel, the channel width is twice the diameter of the spheres (top movie) and 2.5 times the diameter of the spheres. In the first case the spheres organize themselves in two lears one sliding on top of the other with very little movement across layers. In the second case the layering is almost absent. (For the best view, run the two movies simultaniously.) Consequently the effective viscosity of the top case (integer confinement) is less than the bottom one. The relevant paper is here. The movies were generated by Walter Fornari. This work was done in collaboration with, Luca Brandt, Walter Fornari, and Francesco Picano.
Motion of a deformable capsule through a microfluidic device we have proposed. The left is for Ca = 0.05 and the right is for Ca = 0.3; where the capillary number Ca = mu U /Gs. Here mu is the dynamic viscosity, U the typical flow velocity and Gs the shear modulus of the membrane of the capsule. Smaller capillary number implies stiffer capsules. The two capsules follow distinctly different trajectories after going past the half-moon obstacle. T The background is a pseudo-color plot of vertical component of velocity. The color on the surface of the capsule shows the variation of the major principal tension. Movie made using the software visit. Direct Numerical Simulations are done by a code, built on top of NEK5000 written by Lailai Zhu. The device and its operation is described in detail in this paper. The work is done in collaboration with Luca Brandt, Cecilia Rorai and Lailai Zhu.
Imagine you are driving in a storm. The circular object at the middle of the domain is your (spherical) car, the storm comes from the bottom of the picture. This is a visualization of such a flow using Direct numerical simulation (immersed boundary method) of the equations of incompressible fluids in two-dimensions. The black circle at the center of the domain is the circular object. The plot shows the vorticity as a contour plot. The values of vorticity inside the circular object are not physical, chosen to impose the correct boundary condition at the boundary of the circular object. Simulations are done with the pencil-code (https://code.google.com/p/pencil-code/). Please look at the high-definition version for best resolution.
A movie generated from spectral simulations of two-dimensional turbulence. The different colors show different values of vorticity. The black dot is a Lagrangian particle being advected by the flow. The number at the top of the box gives time in code units. The most interesting event happens at the later part of the movie when the particle gets trapped in a vortex. The vortex is not stationary in space but moves, but the trapped particle moves with it. A mathematical description of the phenomenon in terms of long-tailed probability distribution functions is given in this paper. The movie was created by Samriddhi Sankar Ray, the spectral code was written by Prasad Perlekar, Samriddhi Sankar Ray and myself.
A movie generated from simulations in spherical coordinates using the pencil-code to solve for the MHD equations in a bi-layer. The recurrect eruptions are models for Coronal Mass Ejections (CMEs). The movie was created by Joern. Warnecke. The relevant paper by Joern, Axel Brandenburg and myself contains further details.
Last modified: Thu Apr 26 12:20:55 CEST 2012