An apparatus is provided in one example embodiment and includes a plate having a plurality of perforations configured in a pattern. The pattern includes the plurality of perforations arranged in concentric circles centered at a point. Each of the perforations is a closed shape comprising four edges, with rounded corners between adjacent edges, with two opposite edges of each of the perforations including non-parallel straight lines and two other opposite edges comprise concentric, offset curved lines. The non-parallel straight lines may form an angle with a vertex at the point, and the concentric curved lines may be centered at the point. The perforations in each concentric circle may be angularly spaced around the point. The apparatus may further include a substantially circular fan.