ALOFT-FT Frequently Asked Questions
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What operating systems does ALOFT-FT support?
ALOFT-FT installs and runs with Windows 98/ME/NT4/2000/XP®. The graphics may not work on some Windows 95 computers. The program is a 32 bit application and will NOT run under Window 3.X with win32. There are no plans to support Windows 3.X, Macintosh® or UNIX at this time.
What is the difference between ALOFT, ALOFT-FT, ALOFT-CT and LES?
ALOFT is the general name for the family of programs which include ALOFT-FT™ (flat terrain) and ALOFT-CT™ (complex terrain). Presently only ALOFT-FT is available in a personal computer version. The ALOFT models are based on the large eddy simulation (LES) technique. This technique can also be applied to indoor fires. To avoid confusion, the LES model for outdoor fires was renamed ALOFT.
How do I remove the program from my computer?
You should use the Add/Remove Programs feature in the Control Panel. Deleting the folder with the program will not remove files in the system directory and update the registry. If the folder is with the program is deleted, it will remove the information required for the Add/Remove Programs feature to function properly.
Can I modify the program myself?
The practical answer is no, however, we are interested in your suggestions. Many of the features in the program were suggested by users. The program is rather large and is written in FORTRAN and Visual Basic. The program uses a number of third party controls or routines which can be used in the run-time mode without royalties. To use these routines in the development mode, the user would have to own copies of that software. NIST has filed a trademark application for the name ALOFT™ and variations such as ALOFT-FT™. The use of these names with a modified program would be considered a violation of the trademark. The program can be freely used and distributed since it is in the public domain and not subject to U.S. Copyright.
Can I run the computational portion of the program without the user interface?
While the program could be set up this way we have chosen not to. The user interface is a convenient way to enter the data and provides substantial error checking.
Can I edit the data files with a text editor such as Notepad?
It is possible to edit the data files with a text editor but it is not recommended. If changes are made to a data file that do not conform to the proper data file format, the program may be unable to properly interpret the data. Directly editing a data will not allow the user to bypass the limits set in the user interface. The data is always rechecked before running the computation.
How can I speed up the program?
There are two ways to speed up the program. The most obvious and costly is to use the fastest computer possible. The most important is to make a prudent selection for the downwind distance. ALOFT-FT computes the solution starting at the fire and works downwind. Thus, the greater the downwind distance, the greater the computation time. The computation time is not directly proportional to downwind distance since the program uses variable time stepping and some functions are independent of downwind distance.
Can I get a printed copy of the User Guide?
The user guide is included with the program in the Windows help file format. This saves publication cost and ensures the guide is always up to date. A windows help file cannot be viewed properly with a word processor. The help routine can be used to print some or all of the guide.
Where can I find the equations used in ALOFT-FT?
The principal technical reference for ALOFT-FT is available for download.
NISTIR 5958 Smoke Plume Trajectory From In Situ Burning of Crude Oil in Alaska: Field Experiments and Modeling of Complex Terrain. McGrattan, K. B.; Baum, H. R.; Walton, W. D.; Trelles, J. J.
NISTIR 5958 includes the equations and comparison of model results with experiments for ALOFT-FT and ALOFT-CT. This is a comprehensive reference but it is a large file.
See ALOFT-FT Download for information on downloading this document.
Additional ALOFT references may be found in BFRL Publications Online and searching under the author name McGrattan.
What are the limitations for using ALOFT-FT?