Prediction of exterior noise propagation from powertrain and exhaust locations in a combine harvester.

Exterior noise regulations will also be affecting the development of agricultural equipment very soon, especially for "drive by" events. These events can be simulated in order to assist engineers to understand if the equipment will pass the regulations, or to evaluate noise control initiatives to ensure the compliance to this norm. In the case of combine harvesters, the size of the machine creates additional difficulties when using numerical methods such as finite element (FEA) or boundary elements (BEM). Therefore, other tools such as ray tracing can be used to perform these predictions. In this paper, numerical models are created to predict exterior transfer functions (P/Q) to be compared to experimental results. It was concluded that ray tracing provided an adequate method to predict interior to exterior transfer functions in an efficient way producing accurate results.