A computational model has been used to describe Barchan and transverse dunes.
My Diploma thesis about transverse and Barchan dunes: Thesis (pdf-file)
Further work has been done to describe the interactions between Barchan dunes and to understand how stabilizes an entire field.
The saltation sand flux can also be maintained by other forces than wind shear stress:
Here I've got some films of my work:
A smaller Barchan passes a bigger one
The same but with a smaller dune, two small Barchans leave the horns
A simulation of a field of transverse dunes with periodic boundary conditions
(These are very fast, better see in slow motion)
A small barchan dune calculating the wind only in one dimension Small Barchan
A small barchan dune calculating the wind in 2 dimensions Small Barchan
A mixture between barchan and transversal dune Mixture