关键词: 金字塔沙丘, 流场结构, 发育模式

Abstract: Pyramid dunes are characterized by their large size,pyramidal morphology, and radiating sinuous arms. Based on the experiments for the wind-tunnel flow patterns of trihedral pyramid dune models,combined with field observations,we found that apart from the flow pattern like that existing at the surface on the bar can dunes,there are particular"E"flow pattern at the surface on the lee slope of the pyramid dune model.It is the complicated flow patterns which are resulted from multi-directional wind regime that makes the multi-angle pyramid dune with concave faces.On these grounds,a new model for pyramid dune formation by development of barcan dune(including their compound forms)has been advanced in this paper.

Key words: Pyramid dune, Wind tunnel, Wind regime