Control of Boundary Layer Separation and the Wake of an Airfoil using ns-DBD Plasma Actuators

Ashcraft, Timothy

doi:10.2514/6.2016-0839

Cited by 7 publications

(1 citation statement)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Choosing an optimum value for excitation frequency has been a challenge in flow control applications. Generally, the frequency of natural vortex shedding is selected as the optimum excitation frequency for separation control (Chun and Sung, 1996; Darabi and Wygnanski, 2004; Corke et al , 2006; He et al , 2009; Clifford et al , 2014; Ashcraft et al , 2016). As a shear layer has the highest receptivity in the range of frequency of its natural vortex shedding, actuation in this range has the most impact on instabilities development.…”

Section: Introductionmentioning

confidence: 99%

Dual-position excitation technique in flow control over an airfoil at low speeds

Ebrahimi

Hajipour

Ghamkhar

2018

HFF

View full text Add to dashboard Cite

Purpose The purpose of this paper is to control flow separation over a NACA 4415 airfoil by applying unsteady forces to the separated shear layers using dielectric barrier discharge (DBD) plasma actuators. This novel flow control method is studied under conditions which the airfoil angle of attack is 18°, and Reynolds number based on chord length is 5.5 × 105. Design/methodology/approach Large eddy simulation of the turbulent flow is used to capture vortical structures through the airfoil wake. Power spectral density analysis of the baseline flow indicates dominant natural frequencies associated with “shear layer mode” and “wake mode.” The wake mode frequency is used simultaneously to excite separated shear layers at both the upper surface and the trailing edge of the airfoil (dual-position excitation), and it is also used singly to excite the upper surface shear layer (single-position excitation). Findings Based on the results, actuations manipulate the shear layers instabilities and change the wake patterns considerably. It is revealed that in the single-position excitation case, the vortices shed from the upper surface shear layer are more coherent than the dual-position excitation case. The maximum value of lift coefficient and lift-to-drag ratio is achieved, respectively, by single-position excitation as well as dual-position excitation. Originality/value The paper contributes to the understanding and progress of DBD plasma actuators for flow control applications. Further, this research could be a beneficial solution for the promising design of advanced low speed flying vehicles.

show abstract