Case Study: VTT Technical Research Centre reduces exhaust noise with Hexagon’s Actran

VTT Technical Research Centre - Customer Case Study

VTT Technical Research Centre of Finland was engaged by Wärtsilä to address a specific noise complaint originating from a factory engine test. The challenge was a dominant, low-frequency exhaust noise at 94 Hz from a W6L32E engine, which persisted even though overall sound levels were technically within legal limits. This particular tonal noise was causing significant annoyance in a nearby residential area.

Using Hexagon's Actran software, VTT created a detailed vibro-acoustic model of the engine's exhaust silencer and duct system. The simulation from Hexagon identified that the problematic noise was caused by a resonance in the inlet ductwork. A simple modification was proposed to extend the silencer inlet by 1.4 meters. Once implemented, this solution dramatically reduced the problematic noise by 20 dB and cut the total exhaust noise by 10 dB, effectively resolving the issue.

VTT Technical Research Centre

Erin Komi

Research Scientist