Computational Fluid Dynamics study on the performance and mechanism of suction control over a high‐rise building

Abstract

In order to reduce the wind-induced drag and improve the wind-resistance performance of a high-rise building, active suction control was proposed to investigate its drag-reducing property through Computational Fluid Dynamics (CFD) method. The numerical method was validated by the experiment of suction control over a backward-facing step fl ow. Effects of the dimensionless suction fl ux, the suction angle and the slot size on drag reduction for a high-rise building model were analysed, and the detailed fl ow fi elds (including the time-averaged stream and vorticity fi elds), the boundary layer development and turbulence characteristics like turbulent kinetic energy for the suction models were presented to discuss the mechanism of suction control. The results indicate that suction is very effective in reducing the wind-load of a high-rise building model, and only the dimensionless suction fl ux is important, while the orifi ce geometrical parameters and the suction velocities show little infl uence on drag reduction. The mechanism of suction control is concluded that suction can bring more fl ows around the windward face, restrain the fl ow separation and decrease the width of the wake for the suction models. low-velocity fl uid from the boundary layer and to defl ect the high-momentum free-stream fl uid towards the surface of the body (Greenblatt and Wygnanski, 2000;Collis et al., 2004). Its aim is to restrain or avoid separation in the fl ow fi eld around the bluff or streamlined body, thereby improving the aerodynamic performance, such as increasing the lift and decreasing the drag. Suction, as originally proposed by Prandtl, was actually the fi rst method used for the separation control and dragreduction of a cylinder column (Schlichting and Gersten, 2000). In recent years, it has been widely used in many aspects, such as to improve the aerodynamic characteristics of the airfoils (Huang et al., 2004) or the compressor cascade (Song et al., 2005), to control the fl ow separation over the backward-facing step fl ow (Uruba et al., 2007), to control the vortex shedding of the square cylinder in the channel (Layek et al., 2008), and to reduce the wind loads on high-rise buildings (Zheng and Zhang, 2010).In our previous work (Zheng and Zhang, 2010), the Computational Fluid Dynamics (CFD) method was used to investigate suction control on wind-load reduction for a high-rise building, and the effects of slot position, suction angle, slot size and dimensionless suction fl ux on the drag reduction (DR) were also analysed. In this paper, we aim to further investigate the performance and mechanism of the suction control on the DR for the models, and examine the time-averaged stream and vorticity fi elds, boundary layer development, and turbulence characteristics like turbulent kinetic energy in the context of the suction-modifi ed fl ows. NUMERICAL METHOD Analytical model and computational domainThe analytical model was a high-rise building, with a height of 600 mm (H = 600 mm) and a width (depth) of 162 mm (B = D = 162 mm)...

Control of the flow around a finite square cylinder with a flexible plate attached at the free end

“…On the contrary, C p ̅̅̅ on the leeward face reduces (more negative) gradually with increasing z * , suggesting that the non-uniform C d ̅̅̅ along z direction (figure 5a) is largely associated with the non-uniform C p ̅̅̅ on the leeward face, similar to that found by Rastan and Alam (2021) using large eddy simulation (LES). If the finite square cylinder is fully immersed in a turbulent boundary layer, C p ̅̅̅ on the windward surface increases toward the free end, since U∞ enlarges with increasing z * within the turbulent boundary layer (Kikuchi et al 1997;Wang et al 2017;Zheng and Zhang, 2012). That is, the non-uniform C p ̅̅̅ on both windward and leeward surfaces contributes to the variation of C d ̅̅̅ along the z direction.…”

Current and emerging deep-learning methods for the simulation of fluid dynamics

“…Fluid dynamics is a scientific discipline of critical importance in several areas of science and engineering, such as aeronautics [16,17], civil engineering [18], biology and medicine [19,20], environmental science [21] and computer-generated imagery (CGI) [22]. The availability of fluiddynamics data has been increasing over the last decades owing to improved measurement devices and highly parallel computational simulations, which have enabled the recent application of DL techniques to fluid dynamics with different goals.…”

Effects of wall suction/blowing on two-dimensional flow past a confined square cylinder

“…Suction/blowing method, one of the most effective active flow-control methods, has been widely used in many aspects, such as bluff body (Mathelin and Maitre 2009 ; Weller et al 2009 ; Zheng and Zhang 2012 ; Shtendel and Seifert 2014 ; Chen et al 2013 ; Muralidharan et al 2013 ; Boujo and Gallaire 2014 ; Sohankar et al 2015 ; Layek et al 2008a ), backward-facing step (Kaiktsis and Monkewitz 2003 ), symmetric sudden expanded channel (Layek et al 2008b ), and plane Poiseuille flow (Gao and Lu 2006 ). In recent years, several researchers have studied the effect of suction/blowing on flow past the bluff body.…”

“…Weller et al ( 2009 ) applied a low-order model to determine a feedback control set by placing blowing and suction actuators on the square cylinder to reduce flow unsteadiness of the bluff body wake at Re = 150. Zheng and Zhang ( 2012 ) investigated the performance and mechanism of suction control on drag reduction for a high-rise building. Shtendel and Seifert ( 2014 ) conducted experiments on active flow control to control flow around a circular cylinder at transitional Reynolds number, for drag reduction and wake stabilization by applying the combined steady suction and pulsed blowing in close proximity.…”