Barrier

The calculation of the screening effect is based on the standard or guideline selected for each noise type (see Standards). The available calculation options consequently depend on this selection as well. Information on the handling of barriers by a standard or guideline can be found in the following chapters:

Industry: see Industrial Sources
Street: see Roads
Rail: see Railways

Reflections at the surfaces of a barrier are taken into account according to the image source method if

a order of reflection > 0 is selected (see Reflection Tab) and if
the barrier is defined as reflecting by entering a reflection loss or, alternatively, an absorption coefficient.

Note

Depending on the selected standard or guideline additional conditions may apply to generate a reflection at a barrier (or at any other possibly reflecting obstacle), for example a minimum size/dimension in relation to the wavelength.

Dialog options

Name, Memo-Window,ID, ObjectTree, Master

see Dialog Options Name, ID, INFO, ObjectTree, Master in the manual "Introduction to CadnaA"

option „No Reflection“

This is the default setting. In this case, no reflected rays are generated, even when a reflection order larger than zero is selected.

Reflection Loss/Absorption Coeff. Alpha

Either the reflection loss or the absorption coefficient Alpha can be entered, for each side separately. The specification „left“ or „right“ is based on the viewing direction from first to last polygon point.

Via the respective file selector symbols either a reflection type (see Chapter 3 - Obstacles, Reflection Properties) or an absorption spectrum from the local or the global (by SHIFT-clicking) library of absorptions can be selected.

Floating Barrier

see Floating Barrier

Crowning

see Barrier with special crowning