Investigating the Speed and Pressure of the Wind in the Central Part of Varmal Castle Settlement in Sistan, Using CFD Simulation Method

Applying wind energy in Sistan region has been taken into consideration during different historical periods, especially during Qajar period. Varmal castle settlement which is located in Varmal village-environs of Hamoun County-is a Qajar period structure that has used wind power for various applications that resulted in a unique design and architecture. Applying wind power wisely for cooling, natural air conditioning, windmills and other related purposes are among the most important distinguishing features of the design and architecture of the central part of this castle.

The central part of Varmal castle settlement has an irregular plan. Because of the castle’s historical importance and the castle settlement of Varmal, various historical sources have described it. Varmal castle settlement is one of the main Qajar period castles in Sistan area that, in terms of general structure, has been made of three parts including the central part which is the main part of the castle. The wind energy has been used well in this part, and adapting the architecture with the wind is applied on this part. The second part of the castle is located to the north and northwest of the castle and includes a number of buildings with various applications. It has two yards that, regarding the separate space of one of the yards and the architecture of its surrounding appears to be used for particular ceremonies. The third part is located to the south and southwest of the castle and includes buildings and yards. Regarding the good condition of the structures, it seems to be made more recently than other parts.

Based on precious experiences of Sistani people about using the wind energy, undoubtedly there are buildings in the ancient architecture of the region that, as an experienced model, can be combined with modern technology to provide progress in the application of ancient findings. The Wind of 120 Days, the Qous wind, the seventh or the bull-killer wind and Panjak wind are the most important winds of Sistan region among which the Wind of 120 Days is the most famous and the dominant wind which blows from early June to late September (4 months, about 120 days).

Considering “The Wind of 120 Days” in Sistan region that blows with various speeds, the main question of the present research was to match the architecture of this castle with this wind. Therefore, the research question was: how is the design and structure of the central part of Varmal castle settlement matched with the speed and pressure of “The Wind of 120 Days” in Sistan to benefit from various applications of wind energy?

Today, various tools have been applied for simulating scientific plans in different sciences that are quite profiting. One such technique is simulation with Computational Fluid Dynamics (CFD) that has provided researchers with many capabilities.

Global experiences indicate that, during recent decade conducting CFD scientific-computational activities in ancient sites have increased due to the progress of software and hardware systems. Such research in archeology is still in its early stages in Iran. Thus, the aim of the present research was to investigate the status of the design and architecture of the central part of Varmal castle settlement with the direction, speed and pressure of Sistan’s Wind of 120 Days, using CFD simulation methods. This research has adopted a descriptive-analytical methodology based on documents and library resources and field studies. In order to be matched with Qajar period, 52-year meteorological data were collected, and available architectural data of the years 2014 and 2015 were also gathered. The architecture mass was designed using Revit software, and UrbaWind-Meteodyn software was used for preparation. Using Ansys Fluent software, CFD was run for simulation in the buildings of the central part of Varmal castle settlements. The results of simulation outputs with various speeds and pressures (3, 6 and 15 m/s) and maximum 120 km/h from the earth’s surface up to 2 times the altitude in the above castle show that: the design and architecture of central part of Varmal castle settlement matches well with the speed and pressure of “The Wind of 120 Day” toward north and northwest in such a way that as a natural air conditioner, the central yard’s space causes tangible reduction in the speed and pressure of the wind in internal spaces, and principled design which suited the climate and architectural schemes during Qajar period has prevented from damage to the architecture of the central part of Varmal castle settlement when the wind blew with high speed.