Barchan dunes in two dimensions: experimental tests for minimal models.
A well-defined two-dimensional single barchan dune under the force of a shearing water flow is investigated experimentally. From an initially prepared triangular heap a rapid relaxation to a steady-state solution is observed with constant mass, shape, and velocity. This attractor exhibits all characteristic features of barchan dunes found in nature, namely a gently inclined windward side, crest, brink, and steep lee face. The relaxation time towards the steady state increases with mass. For small dunes we find significant deviations from a fixed height-length aspect ratio. As predicted by recent theoretical models, the migration velocity scales reciprocal to the length of the dune.
Groh
Christopher
C
Experimentalphysik V, Universität Bayreuth, D-95440 Bayreuth, Germany.
Wierschem
Andreas
A
Aksel
Nuri
N
Rehberg
Ingo
I
Kruelle
Christof A
CA