Aerodynamic Drag Reduction and Optimization of MIRA Model Based on Plasma Actuator

Chenguang Lai,Hang Fu,Li Jiang,Bo Hu,Zhiwei Ling

doi:10.3390/act9030064

Abstract

Active flow control of surface dielectric barrier discharge (SDBD) plasma is a technology that converts electrical energy into kinetic energy to achieve flow control. Its main application areas are concentrated in the aviation field. Undoubtedly, few studies have applied it in the field of automobile flow control. Meanwhile, during high-speed driving, there is a serious airflow separation phenomenon at the rear of notch-back cars, which brings a large area of negative pressure to the back of the cars. Due to the huge pressure difference between the front and end of the cars, it will increase the driving drag and fuel cost of the car. In this context, we seek to discuss the control effect on the airflow separation at the rear of the notch-back by using the phenomenological numerical simulation method of plasma flow control. Firstly, the plasma actuator is arranged separately on the rear end of the roof, c-pillar, upper and side of the trunk to study the control effect of airflow separation. After that, the plasma actuators at each position are combined and actuated simultaneously. We try to observe the control effect of airflow separation and select the combination with the best drag reduction effect. In the third stage, an efficient global optimization (EGO) algorithm based on kriging response surface is applied to optimize the supply voltage of the best combination that has been obtained before and obtain the driving voltage parameter of each actuator optimized under this combination. The results show that when plasma actuation is applied at four locations, only the actuation applied to the side of the luggage compartment has a significant drag reduction effect, while in other cases, the drag coefficient will increase. Specifically, drag reduction is better when the actuation is applied at four positions simultaneously. The maximum drag reduction coefficient of the car is reduced by 13.17%.

Highlights

With the rapid development of the expressway, vehicle speed has been constantly improved, which puts forward higher requirements for vehicles’ handling stability and safety
This paper mainly talks about the application of plasma active flow control technology to improve the flow field structure of an automobile tail, so as to reduce drag
The actuation voltage is optimized by an efficient global optimization algorithm, and the drag reduction rate reaches 13.17%

Summary

Introduction

With the rapid development of the expressway, vehicle speed has been constantly improved, which puts forward higher requirements for vehicles’ handling stability and safety. Due to the intensifying energy crisis, improving the fuel economy of automobiles has become an important research direction [1]. The studies on the airflow separation of the rear of the notch-back vehicle generally indicate that the airflow tends to separate at a fixed location (edge of a roof, c-pillar, the edge of trunk lid) (see Figure 1), which mainly consists of two-dimensional and three-dimensional separation structures. Due to the three-dimensional effect of fluid flow, the separated vortexes are very adjacent, and tend to interact with each other, resulting in a more complex airflow structure at the rear of the vehicle [2,3].

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