The Wind-tunnel Experiment Study On Growing Mechanism Of Nebkhas In The Ebinur Lake Region,xinjiang

Nebkha is a common kind of biological wind deposition geomorphy in arid,semihumid desert and sandy coast. It has important significance in the aeolian geomorphology, monitoring and evaluating land desertification and regional environmental evolution and so on.In this paper, the typical nebkha is the research object in the Ebinur lake region in Xinjiang. According to Aeolian geomorphology, Aeolian physics, Phytoecology and other discipline theory. On the base of Aeolian geomorphology and Phytological investigation of the nebkha in wild, the wind-tunnel imitative experiment has been carried out in order to explain the growing mechanism of the nebkha. Through comprehensive analysis of the conclusion of the wind-tunnel imitative experiment of the nebkha flow pattern,the initial conclusions can be summarized as follows:1,The change of nebkha slope has acted remarkably on it's flow pattern. The difference of structural character which the change of nebkha slope has acted on it's flow pattern, appears the windward slope of flow speed-up and the leeward slope of eddy-flow.2,The change of Tamarix nebkha plant'closeness-degree has acted remarkab- ly on its flow pattern. In the leeward slope of the Tamarix nebkha, the flow pattern of weaker closeness-degree of the Tamarix nebkha grows stronger eddy-flow. But the flow pattern of stronger closeness-degree of the Tamarix nebkha grows weaker eddy-flow. However, the change of Tamarix nebkha plant'closeness-degree has acted weakly on its flow pattern in the windward slope of flow speed-up. When the wind speed changed slowly, its influence to the flow pattern become remarkable.3,The change of Nitratria nebkha plant'closeness-degree has not acted remarkably on its flow pattern. When the wind through the better closeness Nitratria nebkha, the small domain reflection eddy becomes in the windward slope of flow speed-up. In the leeward stronger eddy of the Nitratria nebkha, the better closeness Nitratria nebkha is smaller than the weaker closeness Nitratria nebkha in the central area of the leeward-eddy, from its thickness and width.4,The difference of structural character which the change of cover-degree has acted on nebkha flow pattern appears the windward slope of flow speed-up and the leeward slope of eddy-flow. As the cover degree of the Nitratria nebkha increases, the reflection-eddy of Nitratria nebkha windward becomed more remarkably and the influence scope of the reflection-eddy increased remarkably, in the windward slope of flow speed-up. As the cover degree of the Nitratria nebkha increases in the leeward slope of eddy-flow, the change of cover-degree has not acted remarkably on nebkha flow pattern from its thickness and width. But this change has acted remarkably on the inner wind intensity of the leeward-eddy.5,The significance difference exists in the flow pattern character of Tamarix nebkha and Nitratria nebkha. In the windward slope of flow speed-up, the flow pattern of Tamarix nebkha becomes upwind eddy speed-up scope, and the flow pattern of Nitratria nebkha becomes upwind speed-up scope. The coverage area is formed in the flow pattern of the Tamarix nebkha, but the Nitratria nebkha not. And the leeward-eddy scope of the Tamarix nebkha is far bigger than Nitratria nebkha's.