ACOUSPROPA, 3D ACOUSTIC NUMERICAL MODELING, FROM THE INSIDE OF INDUSTRIAL WORKSHOPS TO OUTSIDE AND LONG-DISTANCE RECEPTION POINTS, TAKING INTO ACCOUNT THE EFFECT OF UPWIND AND DOWNWIND CONDITIONS

摘要

Everyday needs of acoustics consultants are to be met by relevant, fast and user-friendly software. Relevant, because their responsibility is engaged; fast, because time is money; user-friendly for obvious reasons. AcousPropa is the result of thirty years of practice and experimentation carried out by Gamba Acoustique. The model is based on Lambert's law reflection hypothesis and the resolution of a visibility matrix for the calculation of reverberated noise levels. Initiated in the mid 1980s for occupational noise problems, it was then adapted to meet inside-to-outside calculation needs (and reverse); secondary noise sources can be automatically created, to represent the sound power level radiated through the walls, deriving from upstream noise field and sound reduction index of walls, doors, windows, ... In the early 2000s, wind farm projects began to be developed in France. We were not satisfied with the ISO 9613-2 calculation method for wind turbines, so after a few years of research and a lot of comparisons between calculation and measurements, we implemented a noise path calculation that takes into account the influence of wind and temperature gradient, allowing also upwind conditions assessment. This noise path calculation can be used for any kind of source, high position sources like chimneys for instance, or low position sources. Throughout examples, we will show how complex propagation issues in the real world can be modelled and calculated with a rather good accurracy.