Division: Aerodynamic noise - Commission Directive (EU) 2015/996 of 19 May 2015 establishing common noise assessment methods according to Directive 2002/49/EC of the European Parliament and of the Council (Text with EEA relevance)

Aerodynamic noise is only relevant at high speeds above 200 km/h and therefore it should first be verified whether it is actually necessary for application purposes. If the rolling noise roughness and transfer functions are known, it can be extrapolated to higher speeds and a comparison can be made with existing high-speed data to check whether higher levels are produced by aerodynamic noise. If train speeds on a network are above 200 km/h but limited to 250 km/h, in some cases it may not be necessary to include aerodynamic noise, depending on the vehicle design.

The aerodynamic noise contribution is given as a function of speed:

$L_{W,0, i} = L_{W,0,1, i} (v_{0}) + α_{1, i} \times \lg (\frac{v}{v_{0}})$	dB	For h = 1	(2.3.13)
$L_{W,0, i} = L_{W,0,2, i} (v_{0}) + α_{2, i} \times \lg (\frac{v}{v_{0}})$	dB	For h = 2	(2.3.14)

where

v ₀ is a speed at which aerodynamic noise is dominant and is fixed at 300 km/h
L_W,0,1,i is a reference sound power determined from two or more measurement points, for sources at known source heights, for example the first bogie
L_W,0,2,i is a reference sound power determined from two or more measurement points, for sources at known source heights, for example the pantograph recess heights
α_1,i is a coefficient determined from two or more measurement points, for sources at known source heights, for example the first bogie
α_2,i is a coefficient determined from two or more measurement points, for sources at known source heights, for example the pantograph recess heights.

Division Aerodynamic noise