  High-fidelity simulations are performed to study active flow control
techniques for alleviating deep dynamic stall of a SD7003 airfoil in plunging
motion. The flow Reynolds number is $Re=60{,}000$ and the freestream Mach
number is $M=0.1$. Numerical simulations are performed with a finite difference
based solver that incorporates high-order compact schemes for differentiation,
interpolation and filtering on a staggered grid. A mesh convergence study is
conducted and results show good agreement with available data in terms of
aerodynamic coefficients. Different spanwise arrangements of actuators are
implemented to simulate blowing and suction at the airfoil leading edge. We
observe that, for a specific frequency range of actuation, mean drag and drag
fluctuations are substantially reduced while mean lift is maintained almost
unaffected, especially for a 2D actuator setup. For this frequency range, 2D
flow actuation disrupts the formation of the dynamic stall vortex, what leads
to drag reduction due to a pressure increase along the airfoil suction side,
towards the trailing edge region. At the same time, pressure is reduced on the
suction side near the leading edge, increasing lift and further reducing drag.
