title: Plasma flow control in an S-shaped intake: measurement and computation
Creators: name: Jiang, Fan
Publisher: name: University of Glasgow
Year: 2025

description: In modern aerospace engineering, flow control is an engineering technique that regulates fluid motion through active or passive methods to achieve specific performance objectives or optimise flow characteristics. The primary objectives typically include reducing drag, enhancing lift, suppressing flow separation, mitigating turbulence, and improving overall efficiency.

In recent years, a novel active flow control approach, known as dielectric barrier discharge (DBD) plasma flow control technology, has garnered significant attention. The DBD plasma actuator typically consists of two electrodes, with one electrode covered by a dielectric layer to limit current and prevent the occurrence of arc discharge. During operation, a high-frequency, high-voltage alternating current is applied between the two electrodes, ionising the surrounding air and generating plasma. In this process, charged particles within the plasma are accelerated under the influence of the electric field, colliding with neutral particles in the vicinity to produce a volumetric force (electrohydrodynamic force). This force enables control of the flow field. Due to its advantages, including the absence of mechanical components, rapid response, low energy consumption, and suitability for large-area deployment, DBD plasma flow control demonstrates immense potential for applications.

The relatively small magnitude of the volumetric force generated by dielectric barrier discharge significantly limits its practical applications in flow control. According to existing literature, there is a lack of theoretical foundation supporting DBD plasma actuator performance enhancement through a substantial increase in induced velocity. Therefore, this study aims to explore the potential of DBD plasma technology in broader application domains, building upon the currently known physical characteristics of DBD plasma.

Previous studies have been constrained by the limited magnitude of the volumetric force induced by DBD, leading to the selection of relatively small-scale models with simple geometries as experimental subjects. Moreover, the effectiveness of DBD actuators diminishes significantly with increasing freestream velocity, restricting their application primarily to low-speed environments. These limitations have resulted in a predominant focus on low-Reynolds-number scenarios in prior research. Under such conditions, the applicability of DBD plasma flow control in more complex flow fields remains unexplored mainly, leaving significant gaps in the existing body of research.

To address the challenges above, this study employs an S-duct model developed by NASA as the experimental subject. This duct features a complex geometric configuration and is relatively large. These characteristics enable the test model to achieve higher Reynolds numbers even in low-speed environments, providing more practical and challenging conditions for investigating the application of DBD plasma flow control in complex flow fields.

This study aims to optimise the internal flow field of an S-duct using DBD plasma flow control technology, thereby improving the airflow quality at the duct’s outlet. The research methodology integrates experimental investigations and numerical simulations. The results demonstrate that this approach offers a novel perspective for performance optimisation of S-ducts and provides valuable references for future studies on DBD plasma flow control and its applications in complex flow fields.