Division: Source directivity - 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)

The horizontal directivity ΔL_W,dir,hor,i in dB is given in the horizontal plane and by default can be assumed to be a dipole for rolling, impact (rail joints etc.), squeal, braking, fans and aerodynamic effects, given for each i-th frequency band by:

ΔL_W,dir,hor,i = 10 × lg(0,01 + 0,99 · sin² φ)

(2.3.15)

The vertical directivity ΔL_W,dir,ver,i in dB is given in the vertical plane for source A (h = 1), as a function of the centre band frequency f_c,i of each i-th frequency band, and for – π/2 < ψ < π/2 by:

{ΔL}_{W,dir,ver,i} = (|\frac{40}{3} \times [\frac{2}{3} \times \sin (2 \times ψ) - \sin ψ] \times \lg [\frac{f_{c,i} + 600}{200}]|)

(2.3.16)

For source B (h = 2) for the aerodynamic effect:

ΔL_W,dir,ver,i = 10 × lg(cos² ψ)

for ψ < 0

(2.3.17)

ΔL_W,dir,ver,i = 0 elsewhere

Directivity ΔL_dir,ver,i is not considered for source B (h = 2) for other effects, as omni-directionality is assumed for these sources in this position.

Division Source directivity