Numerical Investigation of Multi-SDBD Plasma Actuators for Controlling Fluctuating Wind Load on Building Roofs

Zhang Zhang,Hu Hu,Li Li,Wang Wang,Zhao Zhao,Sun Sun

doi:10.3390/app9173493

Zhang Zhang, Hu Hu + Show 4 more

Open Access

https://doi.org/10.3390/app9173493

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Abstract

The present research aims to explore, by large-eddy simulation (LES), the potentiality and mechanism of multiple surface dielectric barrier discharge (multi-SDBD) plasma actuators to manipulate mean and fluctuating wind loads on a low-rise building. Three actuator configurations are located on the roof to induce directional wall jets in different directions. The effects of these configurations on flow structure and wind loads are studied in absence and presence of approaching flow. Results show that all subgrid-scale models can obtain accurate roof pressure, and for the diffusion and convection terms, the bounded central differencing scheme can provide more accurate predictions for the roof pressure. The control impact of active actuators gradually weakens with the increase of the approaching flow velocity. The direction of the wall jet can determine the position of the limited roof region with the reduced mean pressure coefficient. The multi-SDBD actuators continue to absorb the upstream flow and blow this flow downstream, meaning the wall jet exerts strong pressure on the local roof area at the end of the jet, which results in a significant reduction of the mean pressure coefficient. Furthermore, the counter-rotating vortices caused by the wall jet restrain the size and strength of the vortex shedding, thereby achieving the purpose of reducing the fluctuating pressure coefficient. Further analysis of the instantaneous vorticity fields indicates that the intensity and size of streamwise shedding vortices can be restrained by small-scale spanwise vortices induced by the plasma actuators. Under the action of the wall jet blowing from the trailing edge to the leading edge, the fluctuating lift and drag coefficients can be reduced by over 15% and the fluctuating pressure coefficient can be reduced by about 20% from the no actuation situation.

Highlights

Typhoons are some of the major natural disasters faced by human beings, which have brought great financial losses and casualties
Dong et al [10] proposed that the drag reduction of a scaled train model can be obtained by using a surface DBD (SDBD) plasma actuator to suppress the flow separation
In these figures and the subsequent similar figures, the upper and lower electrodes are illustrated by black rectangular regions, and the height of these regions is ten-times larger than the used electrode thickness to show the position of the actuators clearly

Summary

Introduction

Typhoons are some of the major natural disasters faced by human beings, which have brought great financial losses and casualties. Li et al [4] pointed out that roof spoilers close to the gable wall had a noticeable reduction effect on wind pressures on the roofs of low-rise, gable-roof buildings, and mean wind pressure can be reduced by 95% on the local roof area These passive methods had a limited operating range. Dong et al [10] proposed that the drag reduction of a scaled train model can be obtained by using a SDBD plasma actuator to suppress the flow separation. They found that the surface temperature of the dielectric and the induced flow velocity were increased as the applied voltage increased.

Conservation Equations

Reference Model and Computational Method

Verification and Validation

Plasma Actuators in Quiescent Air

Flow Control of Plasma Actuators in Flowing Air

Conclusions