Biohydrodynamics MATLAB Toolbox

A. Munnier and B. Pinšon

Institut Elie Cartan (Nancy)
INRIA Lorraine
Projet CORIDA
Images/logovect.gif Images/logo-inria-.gif

Contents

Introduction Demos Some of BhT's features BhT documentation Easy experiment design Efficiency of locomotions strategies About BhT Downloads

Introduction

Biohydrodynamics Toolbox (BhT) is a collection of M-Files for the design, the simulation and the analysis of animal motions in fluids. Animals are modeled as systems of articulated rigid solids. More widely, BhT allows one to perform easily any kind of numerical simulation involving 2d motions of solids in an ideal fluid (simulations of so-called fluid-structure interaction systems).
An articulated fish An articulated bird
Images/fish1.jpg Images/fish2.jpg
Images/bird1.jpg Images/bird2.jpg

Demos

BhT includes tools to realize short videos. Click on the images below to play the related QuickTime movies.
Swimming fish (7.5 Mo)

  • Fish starting from rest.
  • Unbounded fluid domain.
  • Trajectory of the center of mass displayed.
  • Velocity vector of the center of mass displayed.
Images/fish_forward.jpg
Flapping bird (3.1 Mo)

  • Bird starting from rest.
  • Unbounded fluid domain.
  • Flapping optimized to minimize the torques of the joints.
  • Velocity vector of the center of mass displayed.
Images/flapping_bird.jpg
Ellipse-shaped solid in a box filled by a fluid (664 Ko)

  • Bounded fluid domain.
  • Buoyant force taken into account.
  • Collisions with the boundary managed.
Images/ellipse_in_a_box.jpg
Fall of two ellipse-shaped solids in a fluid (932 Ko)

  • Buoyant force taken into account.
  • Collisions between solids managed.


Images/fall_of_two_ellipses.jpg
Six ellipse-shaped solids in a fluid (1.8 Mo)

  • The blue solids have a larger density than the fluid's and the red ones, a smaller.
  • Buoyant force taken into account.
  • Collisions between solids managed.
Images/six_ellipses.jpg
More videos are available in the Demos Gallery page and here.

Some of BhT's features

BhT documentation

BhT contains a complete documentation involving examples and tutorials.

Easy experiment design

Simulations are fast and easy to make. Once you have decided what your simulation will be, all of its features are described in a unique text-file by means of intuitive fields.
Example of what a text-file describing an experiment looks like
max time = 90
time step = 0.1
mesh size = 0.2
fluid density = 1

fish = {
       initial position = [0;0;0]
       initial velocity = [0;0;0]
       colormap = autumn
    link = {
          label = head
          mfilename = bht_ellipse
          settings = [2,0.5,0,0,1]
          density = 1.2   }
    link = {
          label = second
          father = head
          mfilename = bht_ellipse
          settings = [2,0.5,0,0,1]
          hinge coord = [3;0]
          hinge local coord = [-3;0]
          density = 1.2   }
    link = {
          label = third
          father = second
          mfilename = bht_ellipse
          settings = [2,0.5,0,0,1]
          hinge coord = [3;0]
          hinge local coord = [-3;0]
                          }
        }

Efficiency of locomotions strategies

BhT provides tools to study and optimize swimming or flapping strategies in terms of energy, power and torques.
Example of what can be done using BhT as regards energy, power and torques.
Images/energy_bird_optim_efficiency.jpg

About BhT

Downloads