Experimental Study on the Snowfall Flow Control of Backward-Facing Steps Using a High-Durability Designed Plasma Electrode

Abstract

Using a high-durability designed plasma electrode (PA), the plasma actuation effect on both a two-dimensional backward-facing step flow (standard model) and an arc-shaped three-dimensional backward-facing step flow (arc model) was investigated experimentally. First, we searched for plasma operation control conditions suitable for the two-dimensional backward-facing step flow by carrying out experiments using a medium-sized circulating wind tunnel. Next, using the natural-snow wind tunnel of the Hokkaido University of Science, we examined whether an AC-driven PA can control snowfall flow. It became clear for the first time that the amount of snow accumulation can be reduced by more than 20% when the PA is driven at a dimensionless frequency of fH/U = 0.32, where f is the pulsed modulation frequency, H is the step height, and U is the mainstream velocity, and the duty ratio D (the time ratio of PA_ON to the total time when controlled by the pulsed modulation frequency) is equal to 1.0%. It was also confirmed that by masking the arc-shaped electrode parallel to the mainstream and using only the part perpendicular to the mainstream of the PA electrode, the amount of accumulated snow could be reduced by up to 20%. It has become clear that high-durability designed plasma electrodes can control the snowfall flow and reduce the amount of accumulated snow.

Recent Developments on Dielectric Barrier Discharge (DBD) Plasma Actuators for Icing Mitigation

“…For improving the deicing effi-ciency of plasma actuators over an airfoil, Hu et al [192] performed an optimization study for the implementation of plasma actuators on a realistic configuration of the NACA0012 airfoil model and emphasized that the biggest advantage of the AC-SDBD plasma actuator is that it can be simultaneously used for flow control and ice mitigation using the same device, meaning that the actuators can be used for icing control in icing conditions and flow control in the non-icing environment. Recently, Tanaka et al [193] performed an experimental study about snowfall flow control using a high-durability designed plasma electrode, and Lilley et al [194] studied the effects of water adhesion from droplets directly sprayed onto a plasma actuator and its plasma glow recovery. Various forms of deicing and anti-icing actuation based on dielectric barrier discharge were presented and discussed.…”

Novel plasma actuator for mitigation of dynamic stall

“…Plasma actuators, specifically surface dielectric barrier discharge (SDBD) actuators, are surface-compliant electrical devices that can impart momentum into the neighboring fluid through ionization of the local medium inducing Lorentz body force [12]. Despite the small momentum input, plasma actuators have been proposed for a wide variety of uses ranging from aircraft stall control [13,14], deicing [15,16], noise reduction [17], drag reduction [18], tandem airfoil interaction [19], flow mixing enhancement [20], microbial sterilization [21,22] to food preservation [23]. Studies have shown that even though plasma actuators' performance degrade under certain environmental conditions such as excessive humidity [24][25][26], they can be designed to operate in icy [15,16] and wet conditions [27], although this are remains largely unexplored.…”

“…Despite the small momentum input, plasma actuators have been proposed for a wide variety of uses ranging from aircraft stall control [13,14], deicing [15,16], noise reduction [17], drag reduction [18], tandem airfoil interaction [19], flow mixing enhancement [20], microbial sterilization [21,22] to food preservation [23]. Studies have shown that even though plasma actuators' performance degrade under certain environmental conditions such as excessive humidity [24][25][26], they can be designed to operate in icy [15,16] and wet conditions [27], although this are remains largely unexplored. Real world implementation of plasma actuators may be single flight use due to their cheap and simple construction (2 copper electrodes and a dielectric).…”