Scania is always trying to diversify out noise reduction strategies and is currently looking at a way to manipulate the flow turbulence which could lead to an attenuation of the exhaust noise. This needs the development of simulation methods to facilitate the development of Scania’s next generation exhaust system. The target of this Master's Thesis project is to perform CFD simulations with the objective being the study of acoustic characteristics of flow. In particular the ability of the commercial software STAR-CCM+ to capture acoustic phenomena will be investigated by the validation of two simulation cases. Then the same methodology will be applied on real silencer geometries in order to study how flow generated noise could be attenuated by a proper manipulation of the flow..