American Journal of Mechanical Engineering, 2017, Vol. 5, No. 3, 87-90 Available online at http://pubs.sciepub.com/ajme/5/3/3 ©Science and Education Publishing DOI:10.12691/ajme-5-3-3 A Review on the Study of Wind Loads on Multiple Cylinders with Effects of Turbulence and Surface Roughness Zawad Abedin * , Md. Quamrul Islam, Mousumi Rizia, H.M. Khairul Enam Military Institute of Science and Technology, Mirpur Cantonment, Dhaka, Bangladesh *Corresponding author: zawadabedin@me.mist.ac.bd Abstract In the past decades, there have been a great number of studies concerning the flow around circular cylinders. Depending on the researcher’s interests, these studies investigated various perspectives of the flow phenomenon, including the pressure distribution, force coefficients, vortex shedding, Strouhal numbers, flow patterns, etc. Most of these investigations were conducted by means of wind tunnel experiments, and only a few were carried out with full-scale measurements. These previous research work is reviewed in this paper. Since the mean drag and lift coefficients are of the most interest in these study, the data regarding these parameters constitutes the majority of the review work as well. Keywords: tandem cylinder, downstream wave, critical spacing, critical regime, drag coefficient, progressive transition Cite This Article: Zawad Abedin, Md. Quamrul Islam, Mousumi Rizia, and H.M. Khairul Enam, “A Review on the Study of Wind Loads on Multiple Cylinders with Effects of Turbulence and Surface Roughness.” American Journal of Mechanical Engineering, vol. 5, no. 3 (2017): 87-90. doi: 10.12691/ajme-5-3-3. 1. Introduction Wind-resistant design of industrial structures has been given growing attention due to the possible catastrophic effects in case of failure, especially in the areas where extreme wind events are likely to occur. It may not only cause a huge economic loss, but also be devastating to the environment in some cases. Pipe-rack structures are commonly found in petrochemical plants, chemical plants, power plants, etc. In many cases, the calculation of the wind loads on pipe rack structures is not specifically addressed in the current design codes. There have been a great number of studies concerning different perspectives of the flow around circular cylinders (also mentioned as “pipes”). Of primary interest, the mean drag and lift force coefficients C d and C l are required to calculate the wind loads. 2. Flow around a Single Cylinder The research about the flow around a single cylinder can be dated back to more than a century ago. For a smooth cylinder immersed in a disturbance-free flow, the characteristics of the flow are determined by many factors. The Reynolds number is usually singled out as the governing parameter, which is defined as: / Re Vd ρ µ = where, ρ, V and μ are the density, approaching velocity and dynamic viscosity of the flow respectively and d is the diameter of the cylinder. The Reynolds number essentially represents the ratio of inertial to viscous forces. Figure 1 shows the flow field around the single cylinder. Depending on Re, progressive transitions from laminar to turbulent flow take place in the wake behind the cylinder, the shear layer, the boundary layer and then become fully turbulent. The drag and lift coefficients are closely related to these transitions. The function of Cd vs. Re has been well established through a great amount of research. Several flow regimes can be defined based on these variations of Cd. It is also demonstrated that the variations of Cd vs. Re may have different behaviors with changes in free-stream turbulence and surface roughness. Figure 1. Flow Field around Circular Cylinder