Flow Field Simulation and Noise Control of a Twin-Screw Engine-Driven Supercharger

Table 2

Spectrogram data summary sheet.

Supercharger speed (r/min)	Signal basic frequency (Hz)		Basic frequency sound pressure level (dB)		A-weighting total sound pressure level (dB)
	Original model	Improved model	Original model	Improved model	Original model	Improved model
3600	1258.9	1000	88.56	79.39	95	88
6600	1000	1000	94	89.5	98.5	94
8400	1258.9	1258.9	100.9	91	103	97
10,200	794.3	2511.8	101.4	92	104.5	99.8
12,000	1000	794.3	102.5	98.2	106	102