| Popis: |
Aeolian landforms result from the complex interplay of wind, windblown particles, and the surface. Using results from wind tunnel simulations, field studies (including remote sensing), and theoretical considerations, three landforms have been assessed to determine their aeolian characteristics: domical hills, yardangs, and craters. For both domical hills and raised-rim craters, a horseshoe vortex wraps around the obstruction and forms a distinctive zone of erosion and deposition. The formation of linear lee dunes in the wake of some hills and other topographic obstructions may be the consequence of this wind pattern under some conditions dependent upon sand supply and general wind speed. In the evolution of yardangs, hills are eventually sculpted to a 1:4 width-to-length ratio, which from aerodynamical condition is an optimal streamline form. Future work will involve modelling dynamic dunes (made possible with a new wind tunnel facility) and field studies using multiple arrays of field-portable anemometers to obtain concurrent wind velocity profiles around different landforms. |
