EXPLICA · Exhaust Pipe noise radiation Modelling by Innovative Computational Aeroacoustics
FP7 — People (Marie Curie Actions)
- Duration
- 2009-07-01 → 2011-06-30
- EU contribution
- €158,423
- Participants
- 1
- Scheme
- MC-IEF
Lines connect the coordinator with its partners.
Results in brief
Exhaust Pipe noise radiation Modelling by Innovative Computational Aeroacoustics
As outlined in the Strategy Paper Research for a Quieter Europe in 2020, significant research investments are needed to further reduce the road traffic noise in Europe. A major contributor to the noise, especially in urban environments, is the vehicle exhaust system. The radiation of the generated sound to the environment is mainly originating from the tailpipe end of the exhaust pipe. The exhaust jet flow has a temperature higher than the ambient temperature. The non-uniform mean flow and temperature of the exhaust jet as well as the surrounding geometry, i.e. ground surface and automotive body, influence the noise radiated to the environment, yet to what extent is so far an both open question as it has not systematically been studied by numerical methods. The EXPLICA project has two main objectives: 1. Development of a Fourier pseudospectral (FPS) numerical code to predict noise propagation in the exhaust pipe and radiation from its termination including the effects of exhaust jet flow and surrounding geometry, as illustrated in Figure 1. This method will reduce the computation times compared to the state-of-the-art methods. 2. Investigation of the effects of the non-uniform mean flow and temperature of the exhaust jet as well as the geometry surrounding the exhaust pipe on the radiated exhaust pipe noise. The equations governing sound radiation from the exhaust pipe as in the configuration of Figure 1 are the linearized Euler equations (LEE). The non-uniform mean flow and temperature fields that arise in the LEE are solved separately by the Reynolds Averaged Navier-Stokes (RANS) equations prior to solving the LEE. The mean flow and temperature fields do refract the radiated sound waves. Also, acoustical energy is converted into vortices, which is also captured by the LEE. The Discontinuous Galerkin (DG) method is a state-of-the-art method to solve the LEE developed at the host institute and has further been adapted in EXPLICA to solve the LEE for the problem of Figure 1. The method is time consuming and has been used for validation of the developed FPS method. A previous FPS method has been further developed in EXPLICA and applied to solve the LEE for the problem of Figure 1. The FPS method has been validated for simpler cases by analytical results. The capabilities of the FPS have been expanded by a multi-domain methodology, with a coarse grid covering the complete spatial domain and fine grids acting as a subgrid resolution of the coarse grid near local fine scale effect, see Figure 2. This multi-domain methodology does not introduce significant errors compared to the single-domain method and leads to a large speed-up compared to the single-domain methodology.
Data: CORDIS, © European Union
Project objective
As outlined in the Strategy Paper ‘Research for a Quieter Europe in 2020’, written by the CALM network and funded by the European Commission Research Directorate-General, significant research investments are needed to further reduce the road traffic noise in Europe. A major contributor to the noise, especially in urban environments, is the vehicle exhaust system. Noise attenuation of vehicle combustion engines is achieved by incorporating efficient mufflers in the exhaust systems. However, these mufflers might become flow-excited noise generators, aero-acoustic noise sources, themselves. At the host institute, a state-of-the-art hybrid method to study this noise generation has recently been developed. The radiation of the generated sound to the environment is mainly originating from the tailpipe end of the exhaust pipe. The tailpipe end jet flow has a pulsating nature and a temperature different from the ambient temperature. These aspects influence the noise radiation to the environment, yet to what extent is so far an open question. In EXPLICA, the state-of-the-art method developed at the host institute will be used to compute this exhaust pipe noise radiation. The research Fellow already is an expert in applied acoustics and has a high interest in the field of fluid dynamics. EXPLICA provides the opportunity for the researcher to combine both domains and to be hosted at an internationally renowned research group in the field of aeroacoustics. Apart from a well established scientific training environment, the researcher will also be able to participate in a professional organisation of complementary skills training. Combination of the unique scientific perspective, the international experience and the opportunity to set up an own network of aeroacoustic experts, will provide the researcher with very good career perspectives with respect to building up his own academic career.
Original text from CORDIS.
Participants
- KATHOLIEKE UNIVERSITEIT LEUVEN · LeuvenCoordinatorBelgium
Links
Data: CORDIS, © European Union