Research

General area of interest

My current interests include:

  • Vortex methods for 2D and 3D fluid flow simulations.
  • Smoothed particle hydrodynamics.
  • Application of vortex methods to challenging fluid flow problems.

There are two aspects of my research work:

  1. Building the necessary tools of interest using particle methods. Currently we have a powerful 2D vortex method code capable of simulating complex moving geometries. Our current work is focussed on building tools in 3D using both vortex methods and smoothed particle hydrodynamics.
  2. Application of the built tools to various problems: currently we are using the 2D vortex method code to simulate challenging and very interesting problems.

One of the major advantages of particle methods is that they are mesh-free and this allows for very interesting computations. In this context we are currently investigating a few problems of practical interest. One of these is the simulation of horizontal axis wind turbines to assess how well they perform. This is an ongoing project. Additionally, particle based methods tend to be very accurate and cost effective for a certain class of problems (unsteady, incompressible flows). Please take a look at the Publications page for some recent results.

Particle methods

SPH

Along with my students, I have been building a powerful framework for particle simulations called PySPH. PySPH is an open source framework for Smoothed Particle Hydrodynamics (SPH) simulations. The framework allows users to write SPH simulations in pure Python and generates high-performance code that can be run in serial or parallel via MPI. This framework has been under development at IIT Bombay by my students and myself. The latest development version is available at bitbucket.

Vortex methods

My primary research interest is in the computational simulation of fluid flows using particle based methods. I have been involved in the development and study of a high resolution random vortex method to simulate 2D incompressible, viscous fluid flows. The pictures you see in this page do not represent very high-resolution simulations but are pretty pictures used to show the power and utility of particle methods. If you want more details (technical or otherwise) on the vortex method please check my Publications page for more details. If you'd like to see more animations, drop by my office sometime (I have a whole bunch!).

Traditional computational fluid dynamics (CFD) requires the use of a computational grid. In contrast, particle methods avoid the use of a grid and track particles carrying fluid properties. The lack of a grid allows us to handle complex geometries relatively easily and minimizes numerical diffusion due to the grid. The difficulty with the method is that it is harder to implement. However, once implemented the method is very useful.

images/naca0012_f60_a0_w.gif

A NACA0012 airfoil at 0 degree angle of attack and with a split flap deflected by 60 degrees.

Below we have a pretty animation of a heaving ellipse and the vorticity it sheds. This is part of work done by Ranjan Das for his BTech. project on flapping wings.

images/flapping_ellipse_web.gif

An animation of a flapping ellipse.

Scientific data visualization

I am also interested in scientific data visualization but this is entirely from an applied perspective. This work is primarily centered around VTK and Mayavi. Mayavi is a 3D scientific data visualization tool written in Python by me and other collaborators. More information on it is available from my Software page and from the links there.