CAA of an Air-Cooling System for Electronic Devices

Table 1

Explanation of peaks in the acoustic spectra.

Frequency in Hz	Trigger	Annotation
215	Acoustic cavity eigenmode	Front panel slot; Figure 24(a)
278, 403	Acoustic cavity eigenmodes	Card slots; Figures 24(b) and 24(c)
416	Acoustic cavity eigenmode	Mainboard slot; Figure 24(d)
417, 833	Blade passing frequency	Including higher harmonics; Figure 25
333, 667, 1000, 1333	Rotor-stator interaction	Including higher harmonics; Figure 27
1666	Blade-stator interaction	—
2330	First structural eigenmode	At 2320 Hz; Figure 9(a)
2490	Second structural eigenmode	At 2484 Hz; Figure 9(b)