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Erosion by wind is one of the most important factors in desert environment. Prevailing winds can shift sand dunes and affect their accumulation. Also, wind regime determines the direction of sand dune mobility. The aim of this research was to investigate sand drift potential using sand movement models. For this research, wind data between 1986 and 2005 from the meteorological station of Yazd were acquired to examine sand drift potential (DP), and erosive storm winds through different methods. The sand drift potential values show that the resultant drift direction (RDD) is from southwest-west towards northeast-east. The unidirectional index value is 0.47. The Yazd – Ardakan plain is under the influence of a low energy wind regime (DP< 200 VU). The DP index should be considered for planning and development projects and conservation work. Calculations show that under a low energy wind regime, the amount of sand drift flow is 15.74 m3 m-1 year-1. The angular direction of RDD is 77°, measured clockwise from the geographical north. The trend of sand movement is observed following a clockwise pattern. With regard to the monthly sand rose, it is seen that the resultant drift potential is low in September and October (1.91-2.1) while the highest resultant drift potential occurs in May. The results obtained from the analysis of wind rose data indicated that the direction of prevailing winds in the Yazd basin is generally from west to north-west, and the storm winds have been generally directed northwest, and the frequency of winds of a velocity less than 6 m s-1 (threshold velocity) is 93.79% as observed from Yazd meteorological station.

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Research on atmospheric boundary layers in wind farms is an important task. Especially, wind effect on wind turbines installed in mountainous area with complex terrain is complicated. In this research, the wake of a wind turbine and wind flow in complex terrain have studied with computational fluid dynamic (CFD) method in OpenFOAM software. Actuator-disk model with introducing forces, based on Blade Element Momentum Theory, on the disk are used. For simulation of wind turbine in wind farm, Reynolds averaged Navier Stokes equation with k-ɛ turbulence model has been used. Structured mesh was used for simulation domain. Also, main wind direction has been determined from North toward south considering wind rose of area. One of wind turbines is studied by detail. The numerical results show an extended wake effect around 5d (five times the rotor diameter). Wind speed deficit is 26% at this distance. Captured wind power from the simulation is close to real data. Also, wind regime has been studied and analyzed for different seasons. For November, December and January, the time period that wind blows in effective speed, is decreased less than %50 which is important in wind farm design and operation.