Biohydrodynamics Toolbox To BhT's home page  

Demos gallery

This page presents a collection of examples realized with the Biohydrodynamics Matlab Toolbox.
For each example, you can merely play the movie by clicking on the picture or copy-past the DAT-File together with all of the other required additional files and redo the complete experiment by your own.

January, 2009

Ellipse-shaped solid in a filled box

  • The DAT-File.
  • Comments: the solid's density is larger than the fluid's so it falls and collides with the bottom of the box. Since the overall energy is conserved, the solid goes on colliding after its first bounce.

Set of solids colliding

  • The DAT-File.
  • Comments: blue solids'  density is larger than the one of the fluid and red solids' is smaller. Red and blue collide half-way.

Two Star-shaped solids and an ellipse

  • The DAT-File.
  • The boundary M-File for rounded star description
  • Comments: two star-shaped solids collide first against a fixed ellipse then together (see Tutorial #2 in BhT's documentation).

A first simple fish


The bodies hydrodynamically decoupled hypothesis

  • The DAT-File.
  • Comments: how two distant ellipse-shaped solids reciprocally impact each other. Under the classical hydrodynamically decoupled hypothesis, both trajectories would have been straight lines!

Free fall of an ellipse

  • The DAT-File.
  • Comments: The blue ellipse is neutrally buoyant. The density of the red ellipse is greater than the fluid's. It falls and drags the blue one down.

Two fishes crossing

  • The DAT-File.
  • The controls M-File.
  • Comments: Two fishes swim one toward the other and cross. One more time, computations are done without the bodies hydrodynamically decoupled hypothesis.


March, 2009 

New: BhT version 1.5 (June, 2009) will support deformable bodies.

Model of swimming amoebae

  • The amoebae is neutrally buoyant. 
  • The colors give the density inside the amoebae: some areas of the amoebae's body are compressed while others are stretched.
  • The black spot is the position of its center of mass.
Amoeba following a squared trajectory

  • Same model as the preceeding one but the shape-changes cause the amoeba to move along a square.

Model of amoebae swimming along a circle

  • The amoeba can actually swim along a circle of any radius.
Real time control and simulation of the amoeba

Click here and copy-paste the m-File.
Run it and use the keys: 'P' and 'L' to modify the velocity, 'W' and 'X' to steer, and 'G' to enable or disable the grid.

May, 2009

Swimming with non zero mean thrust ?

Is a fish swimming in an ideal fluid able to generate a non zero mean thrust ? 
  • no when the fish is alone in the fluid (no obstacle neither other body) as in movie 1. The fish stops  dead as soon as it stops moving.
  • yes in the other cases (example here with two obstacles in movie 2). 
Movie 1
Movie 2

2008 - A. Munnier and B. Pincon (Insitut Elie Cartan and INRIA Lorraine, Projet CORIDA, Nancy, France).