Aircraft Carrier Burble Mitigation With Alternating Current Dielectric Barrier Discharge Plasma Actuators

Abstract

Vortices shedding off the edges of aircraft carriers produce turbulent airflow in the region aft of the carrier. The phenomenon, known as the burble, generates adverse conditions, including a velocity deficit and a large sudden downwash. Since aircraft on approach travel near stall speed and at high angles of attack, the burble further increases the likelihood of stall. Mitigating burble would make aircraft carrier landings safer for naval aviators. A computational and experimental study has been conducted to examine this phenomenon, and to explore its control. For this latter objective, alternating current dielectric barrier discharge (AC DBD) plasma actuators were used to leverage their known ability to add momentum to the flow and thus reduce shedding from bluff bodies. This project proposed that by reducing vortical shedding, the AC DBDs would attenuate the downwash in the burble. The project tested the effectiveness of DBDs in reducing the downwash for various forcing frequencies A transient solution was obtained in ANSYS Fluent for both the baseline and active flow control cases. Analysis of the experimental and computational data at various spanwise and streamwise locations aft of the aircraft carrier showed that the plasma actuators attenuated the downwash to some degree. The computational and experimental data exhibited similar trends in decreasing the downwash magnitude. Nomenclature B = magnetic field strength E = electric field strength F = body force Q = dynamic pressure Re = Reynolds number V = flow velocity e = charge of electron n = number density q = local charge v = velocity of charged particle α = downwash angle ε d = dielectric constant ε v = permittivity of fluid ρ = fluid density subscripts avg = average i = ion e = electron x = x-direction y = y-direction ∞ = freestream