# Wind Tunnel Test on Windblown Sand Two-Phase Flow Characteristics in Arid Desert Regions
###### Abstract  
Windblown sand two-phase flow characteristics become an essential factor in evaluating the windblown sand load on infrastructures and civil structures. Based on the measured wind characteristics in arid desert regions, windblown sand flow fields with three kinds of sand beds are simulated in the wind tunnel, respectively. The results indicate that the characteristic saltation height of sand particles increases with the wind speed and particle size in the windblown sand flow field. As the sand concentration increases, the wind speed decreases, and the turbulence intensity increases. The concentration, energy, and impact pressure of sand particles increase with increasing wind speed and decrease exponentially with increasing height. At the same wind speed, the concentration, energy, and impact pressure of the coarse sand, fine sand, and mixed sand increases, in turn. Moreover, the variation of kinetic energy with height is similar to that of total energy with height and the proportion of potential energy to total energy is quite small. windblown sand two-phase flow; wind profile; turbulence intensity; energy distribution; impact pressure; windblown sand tunnel test +
Footnote †: journal: Applied Sciences  
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Footnote 1: School of Civil Engineering and Architecture, Hainan University, Haikou 570228, China; [EMAIL_ADDRESS]  
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Footnote 2: Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education, Hunan University, Changsha 410082, China; zhn888263.net  
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[PERSON] pointed out that wind force plays an important role in the formation of the landforms and defined the characteristics of moving sand dust under wind force in the middle of the 19 th century [16], which means the windblown sand began to be noticed. After numerous expeditions in the Libyan desert [17] and wind tunnel tests [18; 19], [PERSON] published \"The Physics of Blown Sand and Desert Dunes\" in 1941 [20], which is known as the symbol of the birth of Aeolian Physics. Up to now, the theories on Aeolian Physics have further systematically developed, which covers aeolian processes, aeolian landforms, geomorphology, environmental impacts, and wind erosion. At the same time, researchers have used various methods in Aeolian Physics, including theoretical analysis, field observation, numerical simulation, wind tunnel tests, and the combination of wind tunnel tests and high-speed photography techniques, etc. [21; 22; 23; 24; 25]. In view of the above, we try to absorb the theory from Aeolian Physics into the research of structural wind engineering, which would provide a new research direction for the windblown sand resistance design of infrastructures and civil structures in arid desert regions. There are a lot of studies on the flow field characteristics that affect the structural wind effect, including the flow field characteristics of monsoon, typhoon, tornado, and other phenomena [26; 27; 28; 29]. However, there are few studies on the flow field characteristics of windblown sand that threaten structural safety. Existing research on windblown sand mainly focus on Aeolian Physics. The observation heights of windblown sand flow in most previous studies are generally less than 10 m; all measured results show that the sand amount decreases obviously with increasing height, and there is rarely collected sand at a height of 10 m [3; 30; 31]. Through long-term field measurement in the Tengger Desert, [PERSON] et al. found that the vertical and horizontal distribution of sand mass flux was expressed with exponential functions and power functions, respectively, [32]. Because the research intention of Aeolian Physics is different from that of structural wind engineering, there is little research on the turbulence characteristics in the field measurement of windblown sand. In fact, since the sampling frequency of the anemometer is lower than 1 Hz, it is also difficult to analyze the turbulence characteristics under the actual terrain conditions, although turbulence has an influence on the characteristics of sand transport.