IB2d!
Open Source FluidStructure Interaction software based on Peskin's Immersed Boundary Method
An easy to use immersed boundary method in 2D, with robust options for fiberstructure models with possible porosity and/or poroelasticity, advectiondiffusion, and/or artificial forcing.
The software has two full implementations  one in MATLAB and another in Python 3. The code can be found on my github site. It also contains over 60 examples that illustrate the breadth and functionality of the code.
If using the code for research purposes, please cite the following three papers:

N.A. Battista, A.J. Baird, L.A. Miller, A mathematical model and MATLAB code for musclefluidstructure simulations, Integ. Comp. Biol. 2015, LINK

N.A. Battista, W.C. Strickland, L.A. Miller, IB2d:a Python and MATLAB implementation of the immersed
boundary method,, Bioinspiration and Biomemetics 12(3): 036003, LINK 
N.A. Battista, W.C. Strickland, A. Barrett, L.A. Miller, IB2d Reloaded: a more powerful Python and MATLAB implementation of the immersed boundary method, in press Math. Method. Appl. Sci. 41:84558480 (2018) PREPRINT, LINK
IB2d Papers!
IB2d Video Tutorials!
Video Tutorials (rough drafts):

Tutorial 1: https://youtu.be/PJyQA0vwbgU

An introduction to the immersed boundary method, fiber models, open source IB software, IB2d, and some FSI examples!


Tutorial 2: https://youtu.be/jSwCKq0v84s

A tour of what comes with the IB2d software, how to download it, what Example subfolders contain and what input files are necessary to run a simulation


Tutorial 3: https://youtu.be/I3TLpyEBXfE

An overview of how to construct immersed boundary geometries and create the input files (.vertex, .spring, etc.) for an IB2d simulation to run using the oscillating rubberband example from Tutorial 2 as a guide.


Tutorial 4: https://youtu.be/4D4ruXbeCiQ

The basics of visualizing data using open source visualization software called VisIt (by Lawrence Livermore National Labs), visualizing the Lagrangian Points and Eulerian Data (colormaps for scalar data and vector fields for fluid velocity vectors)
