The installation of obstacles around sand dune is one of the promising methods to suppress sand movement. We focus on the effect of a small fence installed on a sand dune to clarify the mechanism of the sand movement. 丹迪激光多普勒測速儀 Dantec LDA/LDV（Laser Doppler Anemometer） 丹迪激光多普勒測速儀 Dantec LDA/LDV 丹迪粒子圖像測速儀 Dantec PIV