Cylinder

The cylinder is screening object raising vertically from the ground. The cylinder may have a reflective properties. When entering a cylinder using the mouse, first click to it’s center point and then define the radius.

Screening at a circular cylinder	Reflections at a circular cylinder

By default, cylinders - as with the object „Building“ (see Building) - are modeled without a roof plate, although this is displayed in the 3D-Special view (see 3D-Special View). For sources above roof level the ground attenuation results from the source height above ground and not above roof (as the roof is not a reflecting surface).

Internal Sources

see Building, Internal Sources

Note

When modeling the radiation by cylindrical buildings it is recommend to convert the cylinder first into the object „Building“ (see Convert to, manual „Introduction to CadnaA“) and then to apply the command/ action „Parallel Object“ (see Parallel Object, manual „Introduction to CadnaA“) is a vertical circumferential surface source.

Dialog options

Dialog Cylinder

Name, Memo-Window, ID, ObjectTree, Master

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

Reflection Loss/Absorption Coeff. Alpha

By default, cylinders are not reflecting sound (option „No Reflection“). Selecting one of the options „Reflection Loss“ or „Absorption Coefficient Alpha“ enables to specify via the respective file selector symbol either a reflection type (see Chapter 3 - Obstacles, Reflection Properties) or to address an absorption spectrum from the local or the global (by SHIFT-clicking) library of absorptions.

In this case, reflections from the cylinder’s surface are taken into account up to the first order of reflection applying the image source method, provided that on tab „Reflection“ (see Reflection Tab) in the configuration of calculation at least the first order of reflection is selected.

Button "Geometry"

Via the button „Geometry“ the cylinder’s height is specified (see Object’s Geometry).

Example

Path: Examples\Obstacles\Cylinder - abs Height - Input of Ground Height.cna

Note

When entering the absolute height and the ground height using a value above the actual ground level the same restrictions specified in Building, Button "Geometry" hold for cylinders as well.

Sources in Cylinders do not shield

The option „Sources in Buildings/Cylinders do not shield“ is available for industrial sources (see Industry Tab).