Abstract: The systems and methods of the invention include systems and techniques for controlling a turbulent boundary layer flow with a transverse traveling wave, oscillating at certain selected frequencies, amplitudes and wavelengths, to provide substantial reductions of drag. To this end, the systems and processes can include a boundary layer control system having an object with at least one surface exposed to a medium flowing over the surface. A plurality of excitation elements may be arranged on the surface and these elements are capable of exciting a traveling wave force field in a span-wise direction that is substantially parallel to the surface and perpendicular to direction of the flow. A first component of the traveling wave force field in the span-wise direction is substantially greater than a second component of the traveling wave force field, that is substantially perpendicular to the span-wise direction.