An air flow control device for reducing turbulence on a rotating multi-disc stack. Air flow control device includes a first air dam having cavities formed by a series of alternating plate sections forming gaps therebetween adjacent plates. Gaps define cavities capable of receiving discs when disc stack is rotating. A method for writing data onto an annular writeable surface of a plurality of discs including the steps of mounting the plurality of discs into a coaxial stack, extending one or more dam plates each between a consecutive pair of the plurality of discs and adjacent at least a selected one of the writeable surfaces; and writing data onto the selected surface while a first one of the dam plates overlaps enough of the selected surface so that the first dam plate limits a windage-induced error in the written data.