Abstract:

Wind drying is a crucial factor influencing the wind erosion and transport processes on wet sand surfaces. To explore the mechanisms of wind erosion dynamics on wet sand surfaces， a wind tunnel device was used to simulate the wind drying process on wet sand surfaces at low wind speeds. The experimental results indicate that： （1） The wind drying process on wet sand surfaces with high humidity （above 10%） exhibits an "S" shaped change characteristic with a triexponential distribution. Under constant wind speed， the rate of surface humidity decrease shows a fast-slow-fast pattern， with a turning point humidity value of 5.12%. This value is very close to the threshold humidity value of 4%-5% for wet sand initiation found in existing studies， fully demonstrating that the acceleration of the wind drying process on high-humidity sand surfaces is almost synchronous with the occurrence of wind erosion. （2） Under low humidity （below 5.12%）， the wind drying speed and wind erosion significantly accelerate synchronously at a humidity threshold of 0.829%， which is close to M_1.5. Therefore， wind erosion on wet sand surfaces may be closely related to the form of water presence between particles. Thus， it is inferred that there is a feedback relationship between the wind drying effect and the wind erosion process on wet sand surfaces. When the humidity drops to a certain threshold， wind erosion occurs， and the wind erosion process accelerates wind drying. The wind drying effect at this stage shows a linear change characteristic. Based on the wind drying effect model obtained from the experiment， equations were established for the threshold friction wind speed and wind erosion modulus of wet sand surfaces as functions of humidity. This helps researchers understand the changing characteristics of wind erosion parameters during the wind drying process on wet sand surfaces and improves the related research on the wind erosion dynamics of wet sand surfaces.

Key words: wind desiccation effect, wet sand, wind erosion dynamic process, threshold friction velocity, wind erosion modulus