Numerical Method for Impulse Noise Calculation with Diffuse Sound Reflection

Abstract

Among the noises occurring in industrial buildings, the impulsive noise affects the human body most detrimentally. Since the impulse noise is not constant in time, when choosing and designing means of reducing it, the changes of spatial-temporal characteristics of sound energy should be calculated after emission by a source of sound pulses. In order to assess the energy characteristics of impulse noise, the article proposed a calculation method based on the ideas of the diffuse character of sound reflection from fencing. Developing the method, a statistical energy model was used, which describes the distribution of reflected energy in closed air volumes in time and space. A direct difference method is proposed to implement the computational model. The principles of the construction of the calculation method are stated and its accuracy is estimated. The assessment of accuracy was carried out by comparative analysis of the calculated and experimental data obtained in the buildings of complex geometric shapes under the action of a pulsed noise source in them. It is established that the calculated decreases of sound pressure levels in time at the calculated points are in good agreement with the experimentally determined decreases, and the error in the calculation of the levels does not exceed 2-3 dB. The obtained accuracy of the calculations is sufficient for the design of building-acoustic means of impulse noise reducing. The method allows making calculations in rooms with any complex space-planning parameters.