METHOD FOR PREDICTING ROAD NOISE WHILE TAKING REFLECTED SOUND INTO ACCOUNT

摘要

PROBLEM TO BE SOLVED: To provide a predicting method for road noise which is applicable without any restriction and takes into account a reflected sound enabling road traffic noise to be predicted as an absolute quantity. SOLUTION: This method consists of a 1st step stage for finding a sound pressure level by a border element method and the energy sum of all frequency components by dividing the part between object frequency bands by specific frequency division widthΔf and then finding the insertion lossΔLP (dB) of a noise propagation model taking a structure as a sound reflecting surface into account on the basis of a direct propagation model omitting the mentioned structure at a noise prediction point and a 2nd step stage for finding a direct propagation noise level LF (dB) propagated from a road noise source directly to a noise prediction point while taking only distance attenuation into account and also finding the total noise level LR taking the reflected sound into account from the direct propagation noise level LF (dB) and insertion lossΔLP (dB).