Olive Tree Lab Terrain® is an acoustics software application that can be used for noise barrier design and for noise mapping small to medium scale projects. Olive Tree Lab Terrain® covers the need of acoustic engineers for a noise barriers design tool, acoustic researchers and the academia. The application is focused on two main pillars, accuracy and ease of use.
Sound Path Explorer (SPE)
The Sound Path Explorer, is a module used by OTL-Terrain, an in-house developed algorithm to detect valid diffraction and reflection sound paths from source to receiver in a proper 3D environment. Other than being able to see the contribution of individual sound paths, a new feature is that a user selected individual paths can be calculated, allowing the analysis of their contribution.
Sound Propagation Calculation
Mediterranean Acoustics Research & Development, has created an acoustical calculation engine, the Olive Tree Lab- Acoustics Lib, which simulates sound propagation in a 3D environment. It utilises the principle of wave based geometrical acoustics using sound rays to detect sound paths. Currently a sound ray in OTL-Terrain, carries information on how to lose intensity with distance, how to interact with the atmosphere and how to reflect and diffract when it encounters objects preserving phase information. Eventually our sound ray will acquire sound transmission and refraction properties, thus the acoustical model would be able to analyse phenomena combining outdoor sound propagation, sound transmission and room acoustics at the same time.
OTL Terrain is mainly based on the following methods and their limitations (Please see 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
- Includes ISO 9613-2 calculation methods (equivalent to ANSI S12.62-201x standard, which will soon be adopted in the USA.)
- In this version no atmospheric refraction calculations are included yet.
Olive Tree Lab-Terrain other than providing astonishing noise-sound mapping demonstrating interference effects, it is the only atmopsheric acoustics software which calculates the Impulse Response of the space between source(s) and a receiver. Furthermore, it performs high frequency resolution calculations down to 0.001Hz within a ranges of 0.5 to 100,000Hz, which can also be seen in 1/3, 1/1 octave bands and dB(A).
Olive Tree Lab-Terrain can be used for acoustic engineering, acoustic research and academic purposes.
What's New in Terrain 2.1
- Impulse Response
- Auralisation in mono (for now)
- 3D/2D representation for multiple noise mapping areas, on horizontal, vertical and inclined planes.
- Isolines and calculation values in noise mapping
- User adjusted interpolation in mapping
- User adjusted legend steps in mapping
- Export of mapping results to clipboard
- Absorption coefficients for walls, grounds and barriers
- Flow resistivity values conversion to absorption coefficients
- High frequency resolution calculations down to 0.001Hz within a ranges of 0.5 to 100,000Hzwhich can also be seen in 1/3, 1/1 octave bands and dB(A)
- Up to 1000 reflection and 200 diffraction orders
- Calculation of selected paths contribution in the frequency and time domains
- Precise Graph - Level Before & After insertion of barrier, Noise Criteria, Barrier Insertion Loss, Excess Level above noise criteria
- Barrier Types - at a click of a mouse same barrier is transformed from one type to another, e.g. Γ to Δ barrier type, thin or thick barrier
- Coherent & Incoherent Source contribution
- New image source algorithm which offers reflection detection up to 50 times faster performance
- New diffraction calculation methodology which improves calculation results for multiple diffractions
- Enhanced Noise Sources database
- Other features