Stereo tracking method of granular motion and terrain evolution with small-scaled aeolian barchan dune

Driven forces have a significant influence on the morphodynamics of Barchan dunes. Barchan dunes landscape evolution is often studied by the subaqueous experiments for avoiding observation difficulties in wind-tunnel experiments. However, there are still some differences between the subaqueous and aeolian Barchan dunes. In order to explore the morphodynamics of aeolian Barchan dune, this study proposes new analysis techniques for small-scaled Barchan dunes in wind-tunnel experiments. The techniques feature a simultaneous measurement of morphology evolutions and three-dimensional velocity fields. This breakthrough is achieved by multi-view-angle imaging using two synced high-speed cameras and mirror facets. The stereo imaging improves the accuracy of particles positioning and increases the amount of captured particles. This improvement promotes the three-dimensional particle tracking velocimetry (3D-PTV) technique and thereby provided reliable 3D velocity fields. Also, multi-view-angle imaging can be applied to the photogrammetric of the digital terrain model. With the simultaneous measurement of terrains and 3D velocity fields, the relationship between the formation process and granular mechanism of Barchan dunes are discussed.