AULOS Version 3.2AULOS Version 3.2At the international Hydroinformatics 2006 conference in Nice, France, Dr Barnett introduced the concept of modelling real hydraulic problems in three space dimensions and time by using what he called "3D Lattice solutions" to reduce problem complexity to a manageable level while still working with time-varying solutions in 3D space.
The heart of 3D Lattice solutions is the introduction of flow elements where warped surfaces rather than planes are used to describe the free water surface. Cross-sections may then have the conventional horizontal surface, but need not be parallel for exact mathematical description of the connecting free surface. This allows modelling of curved channels, among other things.
The complete analysis of real hydraulic problems in three space dimensions and time will be beyond the capacity of computers for the foreseeable future, but the combination of CELL Integral theory and 3D Lattice solutions within AULOS now offers users accurate, fast 3D modelling of practical problems.
The development of this facility in AULOS is an on-going theme of the releases in Hydra's Version 3 project. AULOS version 2.5 provided a capacity for multi-layered network connections at 3D nodes. Version 3.1 located cross-sections using horizontal map coordinates as well as a vertical datum. Version 3.2 uses these facilities to generate a highly efficient 3D matrix structure for very fast computational solutions, and completes the mapping of solutions to and from 3D space.
Typically, tens of years of prototype time can now be run in minutes of computing time without any compromise of solution accuracy.
The results lend themselves well to computer-generated animation, as has been recognized by Animation Research Ltd, a specialist company well-known for their work on yacht racing simulation in America’s Cup coverage. ARL now offer post-processing of AULOS results into flood animations customized to client requirements.
In this module of AULOS, users set up the spatial parameters of their model. Cross-section positions introduced in Version 3.1 can now be plotted against a background map, and manipulated to fine-tune the correct position, while automatic monitoring immediately signals any intersection of successive cross-section lines which would cause illegal folding of the implied warped 3D connecting surface.
Once positioned, the cross-section may be regenerated at intervals down to 1m resolution if suitable terrain data is provided. Such data is increasingly available from Lidar survey or similar technology, and may readily be processed using packages such as Surfer from Golden Software (see www.goldensoftware.com).
AulosGrid is an optional separate package that processes the saved results of an AULOS model. It transforms the standard compact result format into map grid files compatible with mapping software such as Surfer, or GIS software. AulosGrid provides data for a series of inundation and flow vector maps at any user-specified 2D resolution down to 1m x 1m for all channels where cross-section map references are given.
AulosLay is an independent program that processes the files produced by AulosGrid, to allow you to select model results for particular moments (“snapshots”) and process them into maps using Surfer or similar mapping packages.
Maps may be prepared showing a choice of depth, water level, local flux vectors, or flow velocities at grid resolutions down to 1m x 1m. For example, depth and velocity vectors can be mapped by overlaying a gridded digital terrain model (e.g. a Lidar-based DTM). AulosLay may be downloaded at no charge from the AULOS web site, so that people concerned with presenting the results of models can access them without using a copy of the AULOS program.
AulosModel can now use high resolution grid data. We recommend the use of Surfer to transform terrain data from standard export formats into a suitable format.
Improvements have been made to improve the reliability of handling difficult weir geometries, such as irregular, almost linear stopbank crests.
AULOS now offers greater flexibility in pump settings, and in structure handling generally.
Initial inspection of result animations has been speeded up by an order of magnitude, taking full advantage of increasing processor power.
Time series handling of long period simulations has been expanded to take full advantage of the unique computation speed of the AULOS 3D Lattice solution.
Chainage along the channel may now be specified in either the upstream or downstream direction, either globally or branch by branch. This lets AULOS accept river data surveyed in either direction, and allows worked examples in textbooks, codes and standards to be reproduced exactly as presented.
The accuracy bias may now be set reach by reach or locally as well as globally, allowing locally difficult reaches to be managed without compromising the solution accuracy elsewhere.
The balance principle at network junctions may now be selected individually as well as globally. This allows the choice between energy balance, water level balance, or intermediate settings to be made according to local conditions.
Recent research has confirmed that the transition between an incised channel and flow over a floodplain is not modelled correctly by a simple Manning formula. An automatic correction is now made if the user has relied on an oversimplified channel description.
Until now, the standard file name extension for AULOS model definition (key) files has been .KEY. This extension is registered by many programs, including some in the Windows operating system, and this can give rise to time-wasting conflicts. AULOS 3.2 and later will save its key files with extension .AKY (Aulos KeY), although the .KEY files will still work.
These are important for use on modern computers. They are now supported as well as the existing parallel port dongles. New users can specify either type, and existing AULOS licence holders can trade in one type for the other.
AULOS now runs on Microsoft Windows Vista as well as on previous Windows releases.