A horizontal axis wind turbine power generation depends upon the aerodynamic performance of its blades. Flow separation is one of the phenomena that causes power loss and consequently decreasing the wind turbine output generation. Since usually the local angle of attack in the inner and middle parts of a blade is much greater than the local angle of attack in the separation onset, the blade section encounters a highly separated flow. Hence, flow control methods are applied in order to reduce or weaken the negative effects of the separation. This paper investigates the effects of the passive flow control method for a horizontal axis wind turbine using validated three-dimensional DES (detached eddy simulation) on an S809 split airfoil. The split in the airfoil thickness causes the flow from the high-pressure zone under the lower surface is injected into the separated area over the upper surface, transporting external energy to the separated zone, hence weakening the separated area. As the result show, the overall performance of this method depends on parameters such as split locations on the airfoil pressure and suction surfaces, the direction of the jet flow with respect to the freestream wind and also the thickness of the split. In this research, two different split locations and four thickness values of 0.5, 1, 2 and 4 percent of chord length are simulated at a range of AOA from 0 to 25 degrees. Noticeably, the results demonstrate that for an appropriate split exit location, the thickness value of 2 and 4 percent of the chord are generated more lift force. The average increase of lift coefficient for these split airfoils at a high angle of attack (17, 20, 22 and 25) are 68.5 and 55.8 percent respectively.

-Introduction: Cites are affected by different forces. Changing Changes in the structure of the economy has caused different reactions from different groups of government, markets and people, that can be traced by its appearance in the city. One of the aspects of the impact of the economy on the city is physical interventions and urban construction, such as urban land use Changes changes, space utilization intensity, building congestion, and urban boundaries change. This study aims to explain the effect of economy on physical changes of the city. The researchers seeks the trace of capital flow in the city. The Research questions are as follows: 1- How is Tehran's exchange rate and construction are related? 2. What is the nature and orientation of capital flow in the city? 3- How is the relationship between land price and physical interventions in 22 district of Tehran?
-Methodology: This is an applied research and is one of among the causal and relational studies. The documentary and library-based methods is are used to collect and interpret data. First, the relationship between the exchange rate and the tendency to build in the city is examined using the index of building permits. In the second step, the level of intervention in the city is examined. In the third step, the district and regional effects of land price on the number of building permits were investigated through the spatial correlation between land price and building permits.
 The study area is 22 districts of Tehran. Tehran is the largest city and capital of Iran that has experienced rapid growth over the years. The area of Tehran has increased from 370 km 2  in 1975 to 751 km 2  in 2015.
-Results and discussion: Currency exchange is associated with economic power. The increase in the exchange rate indicates the depreciation of the currency and the weakening of the economic power of the country. The turbulence in exchange rate fluctuations can be interpreted as instability in the country's economic conditions. At the first, the exchange rate changes and the number of building licenses were studied in different years. Accordingly, 2012 was identified as a breakthrough in exchange rate changes in the country. The result of Wilcoxon test shows that the number of building permits in Tehran before and after the 216% exchange rate jump in 2012, has changed significantly. A comparison of the annual average of building permits shows that the intensity of construction in the city has declined with the dollar price hike since 2012. The results of Kruskal-Wallis test indicate a significant difference among the 22 districts of Tehran municipality in terms of number of building permits and land price.
Eventually, in conditions of economic stability, changes in the city are regular and it is subject to changes in land prices and market demand. But in conditions of economic instability and weakening, the common rules in physical interventions in the city and urban builders are disturbed. The demand elasticity and focus of the builders is limited to the high quality areas of Tehran (zones 1, 2, 3, 4 and 6) which create high value added. This exacerbates Class society.
-Conclusion: The exchange value causes the city to be used as a commodity, the property of power-holders and capital, and to create added value. The easiest way to get [r1] it, is to invest in housing and buildings
With the decline in economic power and the possibility for more power and capital intervention in the city, capital choose chooses one of the following ways.

The phenomenon of space production has two aspects. One is consumer value, which comes from production and use. Second, the exchange value, which is profitable, rentier, intermediary and speculative in nature. The deceptive dimension of power must then be sought in exchange value, . Where where people try to take advantage of it. By transforming the city into a commodity, development becomes a tool for exchange value. The stronger the economy, the less foreign exchange capital flows into the land and the capital flows to production and consumption rather than to the exchange and commodification of limited land resources.
Analyzes Analyses showed that the intensity of construction in Tehran has declined with the dollar jump since 2012.
Analysis of the situation of Tehran's 22 districts shows that there is a significant difference between the number of building permits and the price of land between Tehran municipality areas.