Olive Tree Lab Terrain

Overview

Olive Tree Lab Terrain is a noise prediction software which simulates and predicts Outdoor Sound Propagation and Noise Barrier efficiency, taking into account geometrical spreading, atmospheric absorption, atmospheric turbulence, spherical wave complex ground impedance, reflection and diffraction effects of natural or man-made objects. The results are displayed as level vs frequency or level vs spatial mapping.

Based on state of the art calculation methods and ray detection techniques, which demand computational power and time, Olive Tree Lab Terrain is aimed at small scale projects as opposed to large noise mapping software. It addresses mostly fixed noise sources within a small area where one has control over most of the acoustic parameters involved in the sound calculations. It is based on high frequency resolution calculations, as opposed to just 1/3 octave band analysis, which can also be seen in 1/3 and 1/1 octave bands after being appropriately averaged. OTL Terrain can be used for acoustics engineering, acoustics research and educational purposes. Olive Tree Lab Terrain can assist in designing acoustic solutions based on certain noise criteria in real time response, based on preliminary calculations during the design time.

Calculations

OTL Terrain is a calculations application based on the following methods and their limitations (Reference List):

• Hadden & Pierce Diffraction 3D model implemented with finite impedances faces using Salomons semi-analytical method including ground effects. Multiple barrier diffraction is calculated in a recursive way at any diffraction order. 
• In-house sound path detection methods.

• Ground effect using the One Parameter Theory of Chessell based on Delany and Bazley

• Reflections from finite surfaces based on Clay–Medwin’s work to include Fresnel zones contribution at any order level. 
• Atmospheric absorption based on ISO 9613 -1. 
• Turbulence coherence factor based on HARMONOISE WP3 

In this version no atmospheric refraction calculations are included.

Version 1.4 includes ISO 9613-2 calculation methods.

Terrain Use Cases

Even though Olive Tree Lab Terrain was initially intended to be used as a software application for noise barriers design, practice and daily experience of acoustic has revealed a number of other acoustics related areas that Terrain is remarkably useful. Olive Tree Lab Terrain has proven to be a reliable acoustics software application can be used for noise assessment in small and medium size project, wind turbine noise prediction and small to medium size noise mapping .

Small to Medium Sized Projects

In contrast with traditional noise mapping software applications which focus of city mapping and large areas assessment, Olive Tree Lab is well suited for small to medium projects like problems between neighboring premises, industrial noise and outdoor noise prediction.

Wind Turbine Noise

Acoustic engineers found that Terrain is very useful software application when it comes to deal with wind turbine noise. Wind turbine noise is an important issue that must be considered during the design and placement of wind turbines. Olive Tree Lab Terrain can assist in assessing and dealing with wind turbine noise.

Noise Mapping

Olive Tree Lab Terrain can be used for small and medium scale noise mapping. Terrain can be used for neighborhood noise mapping, industrial noise mapping and noise mapping between neighboring premises.