Roads:

In a road case, we shall consider several points.  We shall consider a minimum number of 1000 vehicles per hour N with a 50km/h minimum velocity (100km/h is the maximum velocity). Then we have a 68 dB(A) noise level at 10m from a lineal road (infinity length). The noise level will be

Leq=68dB(A)+30Log(v/50)+10Log(N/1000)-10Log(r/10)

in the lineal (infinite) road case.

In the curved road case, the program considers a finite element method of calculation. Each small size of road contributes to the total noise level. Each contribution will be given by

Li=-10Log(a/180)

being a the angle of the small road size(degrees).  

To obtain the total noise level, we add the different L_i values following the equation

L_eq= 10.Log[S_i10^(L_i/10)]

In the railway case, we shall calculate the noise level in a similar way. For airports, we shall use the next equation

Leq=Leq(300m)-20Log(r/300) 

where Leq(300m) is the noise level at 300m from the airport.

This model performs satisfactorily for simple sound propagations with no ground interaction or attachment. The application will not consider sound reflections in the ground surface.

Noise map for two roads using noise isolines.

Noise map in the XZ plane for three sources using colour gradient.

Algorithms I - Algorithms II

Environmental software · environmental software solutions