Seagate BARRACUDA 9 ST19171WD - Manual (Page 26)

24 Barracuda 9 Installation Guide, Rev. B
Figure 3 shows two design approaches with one or more fans
used to generate air flow. The air-flow patterns can be created
by the fans either pushing or drawing air. The overall flow pattern
can be directed from front to back, back to front, or side to side.