# Wind Tunnel Test on Windblown Sand Two-Phase Flow Characteristics in Arid Desert Regions
###### Abstract
For this reason, [PERSON] et al. obtained the wind characteristics within 10 m height in typical desert regions through field measurement [33], which could provide a basis for turbulence simulation in wind tunnel tests. The field measurement is mainly used to analyze the wind regime and sand transport rate in arid desert regions, and it is difficult to analyze the influence of the sand concentration on the wind profile and turbulence characteristics in the windblown sand flow field. Through the wind tunnel tests, some researchers analyzed the sand transport rate models with different particle sizes [34; 35], and found that the parameters in the model are affected by the particle size and wind speed. Nevertheless, the actual wind field in desert regions is simulated as a uniform flow field in the wind tunnel, without taking into account the actual fluctuating characteristics, which will lead to the deviation between the test results and the measured results. Additionally, in the existing windblown sand tests, the influence of sand concentration on wind profile and turbulence intensity in windblown sand flow field had not been analyzed in detail. Some researchers also attempted to simulate fluctuating characteristics in the actual environment through the numerical simulation method and analyzed the sand particle's saltation and the evolution of windblown sand flow [31; 36]. However, the application of two-phase flow model and the differences of structure characteristics between simulated windblown sand flow field and actual environment affected the accuracy of the results. Hence, verification by field measurements and wind tunnel tests is necessary. The erosion and damage mechanism of various structures and materials in the windblown sand environment is closely related to the saltation movement of sand particles [37; 38]. As the most important research area of windblown sand flow, the energy and impact pressure distribution of saltating sand particles become the breakthrough point of wind erosion control, wear resistance, windblown sand mitigation and windblownsand resistance design of structures. However, there are few studies on the energy and impact pressure distribution models of sand particles in the windblown sand flow field. The research conducted by [PERSON] et al. showed that the variations in kinetic energy and total energy of sand particles with height accord with the pulse peak modified with power term law [PERSON] et al. (2018). It is also worth noting that the wind tunnel test conducted by [PERSON] et al. did not take the influence of the turbulence characteristics of the incoming flow on the sand transport into account [PERSON] et al. (2018). [PERSON] et al. simulated the sandstorm environment by having the sand fall from the top of the wind tunnel; the results showed that the critical height of the impact pressure profile is approximately 20 cm ([PERSON] et al., 2018). In other words, the impact pressure increases above 20 cm and decreases below 20 cm with increasing height. Furthermore, [PERSON] et al. investigated the influence of the fetch length of the sand tray on the sand transport flux profile through detailed wind tunnel tests ([PERSON] et al., 2018), which showed that when the length of sand tray is larger than the threshold length, the sand transport flux profile is no longer affected, and the threshold length is related to wind speed. Some research focused on a detailed assessment of the effectiveness of various windblown sand mitigation measures along roads, highways and railways in cold and arid regions ([PERSON] et al., 2018; [PERSON] et al., 2018; [PERSON] et al., 2018), while there are few studies on the windblown sand resistance design for infrastructures and civil structures ([PERSON] et al., 2018). All of the above studies need to be carried out based on an in-depth understanding of the characteristics of the windblown sand flow field.