Swimming Cylinder Wake Control with Plasma Actuator

TL;DR

This study investigates the use of plasma actuators to control turbulent flow around a cylinder at high Reynolds number, demonstrating significant improvements in flow quality and aerodynamic coefficients, with optimal placement at 90 degrees.

Contribution

It introduces a novel electrostatic model for plasma actuation in turbulent flow control and compares actuator placement effects on flow and aerodynamic performance.

Findings

Flow quality downstream improved by 8% to 15%.

Lift coefficient variation reduced by 40% to 55%.

Drag coefficient reduced by 75% to 90%.

Abstract

In this research, the effect of utilizing a micro plasma actuator on controlling the flow through a two-dimensional cylinder is investigated using an advanced electrostatic model. Within this model, by solving two elliptic equations, the potential distribution and plasma distribution in the solution domain are determined, leading to the generation of a volumetric force. This force is added to the momentum equations as a source term. The Reynolds number of the flow is set at 20,000, and the plasma actuator operates in a steady manner. Due to the high Reynolds number, the flow is turbulent, and its time-dependent nature is modeled as unsteady. Plasma actuators are symmetrically mounted at 45 and 90 degrees with respect to the free stream, both above and below the cylinder surfaces. The influence of the actuator placement angle on the flow quality downstream of the cylinder is examined. The results indicate an enhancement of flow quality by 8% to 15% downstream of the cylinder. Moreover, improvements of 40% to 55% in the variation of the lift coefficient and 75% to 90% in the drag coefficient are reported. The findings reveal superior performance of the actuator positioned at 90 degrees compared to the 45-degree orientation. This can be attributed to the proximity of the 90-degree actuator position to the point of boundary layer separation initiation. Furthermore, using the actuator positioned at 90 degrees and applying three different voltages of 10, 13, and 16 kV, the impact of flow control on the first cylinder in a tandem arrangement on the downstream flow of the second cylinder is examined. The results demonstrate an enhancement in downstream flow quality of 20% to 26%.