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This work presents ongoing experiments toward developing fundamental understanding of suction and oscillatory blowing (SaOB) flow control mechanisms along with development of accurate and practical CFD simulation methodologies for complex unsteady active flow control systems. Experimental and computational studies were conducted on SaOB actuators' internal flow and external interaction with two zero pressure gradient boundary layers. The experimental work incorporates detailed multi component hot-wire measurements of both laminar and turbulent boundary layers with steady suction and pulsed blowing for a single actuator and an array configuration. Large eddy simulation was employed for the computational model. Simulations were carried out on the actuator internal flow, and the resulting oscillatory blowing jet exit velocity profiles are characterized and fit with a functional form, in order to create simplified boundary conditions for future flow control simulations. Both experimental and computational results show that the suction hole geometry and configuration is an important factor in determining the structure and stability of the downstream laminar as well as turbulent boundary layer flow-fields. Measurements of oscillatory blowing jets interacting with a turbulent boundary layer demonstrate this flow control produces unsteady spanwise and streamwise vorticity components that can be interpreted as counter-rotating streamwise vortex patterns. NomenclatureA = area of suction holes A i = phase-locked coefficients C i = coefficients for functional fit jet velocity C f = skin friction coefficient d = suction hole diameter f = actuator oscillation frequency H = boundary layer shape factor 2 L FB = length of feedback tube L n = nozzle width P in = air supply pressure at actuator inlet P suc = static pressure in suction chamber Q = volume flow rate of suction Re x = Reynolds number based on streamwise distance Re L = Reynolds number based on nozzle width S ij = strain rate tensor s = suction hole spanwise spacing U e = local external velocity U j = jet velocity U r = reference supply jet velocity at converging nozzle U s = suction velocity U ∞ = freestream velocity u',v',w' = turbulent velocity fluctuations w , ṽ , ũ = coherent velocity fluctuations x, y, z = coordinates distance in turbulent boundary layer X, Y, Z = coordinates distance in laminar boundary layer  = linear phase-lock function δ = boundary layer thickness δ * = boundary layer displacement thickness  = non-dimensional spanwise nozzle coordinate θ = boundary layer momentum thickness λ 2 = second negative eigenvalue of the matrix S ij S ij + Ω ij Ω ij  = suction loss factor ρ = air density ν = kinematic viscosity  = phase angle ω x = streamwise vorticity component ω z = spanwise vorticity component Ω ij = vorticity tensor = denotes phase-averaging