Wake Flow Characteristics over an Articulated Lorry Model with/without AC-DBD Plasma Actuation

Kin-Hing Lo,Konstantinos Kontis,Rengarajan Sriram

doi:10.3390/app9122426

Kin-Hing Lo, Konstantinos Kontis + Show 1 more

Open Access

https://doi.org/10.3390/app9122426

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Abstract

The wake flow characteristics of a 1:20 scale articulated lorry model with a linear Alternate Current Dielectric Barrier Discharge (AC-DBD) plasma actuation implemented was experimentally investigated. Time-averaged velocity, turbulence, and vorticity information along the centreline of the model were constructed using a two-component particle image velocimetry technique. In addition, force balance was used to measure the time-average drag force acting on the model with and without the use of AC-DBD plasma actuation. In general, the AC-DBD plasma actuation showed negligible effect in changing the drag coefficient of the test model. Moreover, implementing the AC-DBD plasma actuation around the rear end of the trailer model could neither alter the size nor the reverse flow velocity in the wake region. In contrast, the AC-DBD plasma actuation increased the levels of fluctuation in the flow turbulence kinetic energy and vorticity but showed no observable effect to alter the frequency response of the flow in the wake region. It is deduced that the use of AC-DBD plasma actuation indeed generated no flow control effect at the rear end of an articulated lorry trailer.

Highlights

Flow separation at the rear end of a square-back trailer contributes to approximately 25% of the overall drag that is encountered by an articulated lorry [1]
From the data shown previously about the velocity field downstream of the trailer rear end, it could be seen that using the linear Alternate Current Dielectric Barrier Discharge (AC-DBD) plasma actuation at the rear end of a square-back trailer model shows no observable effects in altering the size and shape of the recirculating bubble
Force balance was used to measure the drag force acting on the articulated lorry model with and without the implementation of the plasma actuation

Summary

Introduction

Flow separation at the rear end of a square-back trailer contributes to approximately 25% of the overall drag that is encountered by an articulated lorry [1]. It is anticipated that significant drag reduction and fuel saving could be achieved if flow separation control could be effectively implemented to reduce the size and strength of the wake region downstream of the trailer rear end. Effective flow separation control over the rear end of square-back articulated lorries could be achieved by installing boat tails [3,4,5,6,7,8] or flaps [9] at the trailer rear end. Other than boat tails and flaps, flow separation control in articulated lorries using vortex generators have been investigated in several studies [11,12,13,14]. No obvious effects in altering the wake size and drag reduction could be achieved using this passive flow control device on the trailer of an articulated lorry.

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Discussion

Conclusion