ORIGINAL PAPER Atmospheric boundary layer simulation in a short wind tunnel S. M. N. Shojaee • O. Uzol • O ¨ . Kurc ¸ Received: 11 September 2011 / Revised: 21 November 2012 / Accepted: 27 April 2013 / Published online: 28 November 2013 Ó Islamic Azad University (IAU) 2013 Abstract This paper presents the design, computational analysis and experimental study of passive device config- urations which utilized in the Ankara Wind Tunnel to simulate the atmospheric boundary layer within the test section. The study here is part of a joint project between the Aerospace and Civil Engineering Departments at Middle East Technical University, which involves testing of high- rise building models in the Ankara Wind Tunnel. The design consists of spires and rows of cubical surface roughness elements at the inlet. The preliminary compu- tational analysis shows that the current design may provide the desired boundary layer thickness at about 4.0 m downstream of the test section inlet, which leaves enough room for the building models to be placed in the test sec- tion. This study also helps obtaining a preliminary under- standing of the boundary layer development and reducing the tunnel operation time and cost during the actual experimentation phase. At the end, experimental results show acceptable results of this study. Keywords Passive device  Spires  Exposure  Modeling  Short wind tunnel Introduction Wind tunnel testing is still the primary source of infor- mation in wind engineering applications. New facilities and new techniques are continuously being developed for the investigation of a variety of environmental and architec- tural aerodynamics-related issues (Abbaspour and Shojaee 2009; Bienkiewicz 1996; Cermak 1995). Determining the effects of wind on high-rise buildings, bridges and other architectural structures is of critical importance and is an integral part of the structural design process (American Society of Civil Engineers [ASCE] 2005). Also, wind profile simulation is very important in environmental pol- lution transportation modeling (Nagheeby and Kolahdoo- zan 2010; Abdullah et al. 2007; Freddy Kho et al. 2007). These wind tunnel tests are generally conducted in specialized tunnels known as ‘‘boundary layer wind tunnels (BLWT)’’ in the literature (Cermak 1982; Peishi et al. 2011), which usually have relatively long test sections (15–20 m) and are specifically designed to create a thick boundary layer velocity profile as well as appropriate tur- bulence levels to be able to simulate the atmospheric boundary layer (ABL) within the test section. When a BLWT is not available, wind tunnel tests may also be conducted in aeronautical tunnels, which have much shorter test sections in general compared to BLWTs. However, this requires a significant effort in terms of designing appropriate devices to be added at the entrance of the test section in order to create the desired boundary layer properties for the ABL simulation. These passive devices come in many shapes and forms but the most frequently used ones are grids, barriers, fences, spires and cubical roughness elements that are generally placed on the test section floor upstream of the test subject (Simiu and Scanlan 1986). During the past 70 years, many researchers S. M. N. Shojaee (&) Department of Aerospace Engineering, Faculty of Mechanical and Aerospace Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran e-mail: nimashojaee@srbiau.ac.ir O. Uzol Department of Aerospace Engineering, Middle East Technical University (METU), Ankara, Turkey O ¨ . Kurc ¸ Department of Civil Engineering, Middle East Technical University (METU), Ankara, Turkey 123 Int. J. Environ. Sci. Technol. (2014) 11:59–68 DOI 10.1007/s13762-013-0371-4