干旱区生态环境知识资源中心

Recent desertification has been one of serious environmental issues. It is important to elucidate mechanisms of the sand movement from sand dunes with considering the relations between the dune shape and the turbulent air flow. This relation can be applied to predict and prevent the desertification. In this study, the shape of the dune surface and the erosion rate are measured by the method of laser-sheet visualization. Laser-doppler velocimetry (LDV) has been used for turbulence measurement. Effects of an installed fence on the erosion rate are discussed with emphasis on influences of its position and height. The erosion has been either suppressed or enhanced by the fence. Since there exist two strong erosion areas due to the backflow and wake induced by the fence. In the present experimental conditions, the top of the dune is the most suitable position of the fence for preventing erosion.