01 

Aerodynamic Noise 

• Unsteady flow phenomena including pressure fluctuation and vortex separation during gas flow excite vibration of air medium and generate noise. 

• It is widely found in pneumatic equipment such as industrial air compressors, large axial fans, turbochargers and electric fans.

02 

Structural Mechanical Noise 

• Metal parts such as gears, bearings and sheet metal vibrate under impact, friction and alternating loads, and the vibration propagates through air as noise. 

• It commonly occurs on machine tools, gear reducers, engines and transmission assemblies.

03 

Liquid-borne Flow Noise 

• Friction and impact between liquid and pipe wall trigger vibration of both fluid and pipe structure, which is categorized as flow-induced vibration noise. 

• Typical applications include industrial water pumps, hydraulic pipelines, control valve assemblies and municipal water supply networks.

04 

Electromagnetic Vibration Noise 

• Alternating electromagnetic force excites the vibration of iron cores and windings, producing noise also known as electromagnetic hum. 

• Main sources cover motors, transformers and variable frequency drives.

05 

Combustion-induced Noise 

• Fuel combustion leads to rapid change of gas temperature and pressure, generating turbulent pulsation and structural vibration.

•  This noise exists widely in combustion equipment like internal combustion engines, industrial boilers and gas turbines.