风洞实验方法在沙漠学研究中的应用

风沙运动和防治风沙、风雪流工程等的模拟实验研究表明,风洞实验技术应用于沙漠学研究中,进行半定量、定量的测量,可以提高研究水平,更好地解决生产实践任务。

EXPERIMENTAL METHODS OF WIND TUNNEL IN THE STUDY OF DESERTS

This paper introduced the large wind tunnel in our inslitite.According to the similarity theory of two phase flow,we expounded the applying range in geography and the limit in open field of the experiments of a wind tunnel,Ranolds number must be increased under the situation without sand-bearing wind.Only when Ranolds number is above 106,a model with angular turns (such as the ceiling of a vehicle and tree branches of a shelterbelt) may not be.affected by the model size and the change of wind velocity,and thus the experimental result can be applied to open field.If there is windborne sand,due to the limited scale of sand particles (sand particles of model being no smaller than 0.08 mm),the distribution of erosion and deposition areas can be estimated by the stream field distribution of experiments,we made experiments of large scale model to reduce error caused by uncompleted similarity.This paper also dealt with the main experimental results after our wind tunnel had been built,we also studied the lifting off mechanism of sand particles by using 2000 pps high Speed photography.It indicates that impact is very important for thd up lifting of sand.For communications and telecommunications,the phenomenon of sand-driving wind and barriers for derivating wind downward in order to prevent windborne sand and snow drift have been studied.We have also proposed several protecting measures,which have gained good results.