DEWEY McMILLIN & ASSOCIATES LTD

AirBlast ^™

PROGRAM DESCRIPTION
AirBlast describes the physical properties of blast waves in air. It allows the user to define an explosion and request that specific physical properties of the resulting blast wave be displayed on screen in a numerical or graphical format. It instantly retrieves and displays data from databases of experimental results made self-consistent by numerical reconstruction and scalable to the user-defined explosion and environmental conditions. AirBlast uses time-tested, robust algorithms beneath a new, improved graphical user interface. It is a 32-bit program which runs under Windows 95/98/NT4. It has only modest hardware requirements. AirBlast is a friendly expert system.

EVENT OPTIONS
Explosive: Several high-explosive materials may be selected, including TNT, ANFO and Pentolite. Gaseous and nuclear explosions are also available. The most comprehensive option allows the user to define a new explosive material. Specific explosives will be added at the particular user's request.
Charge size: Charge size can be specified in SI or British units by mass (weight), or volume in the case of a gaseous explosion, or TNT equivalence (kt) in the case of a nuclear explosion. The user can also define arbitrary units for charge size measurement, 'drums' of user-defined explosive, for example.
Height of burst: Free air, Surface burst and Finite height. In the last case, the charge height above the ground is specified by the user, between 0 and 150 m for 1000 kg TNT, for example. Blast wave properties are provided at distances along the ground surface in both the regular and Mach reflection regions.
Ambient atmosphere: Standard sea-level, Altitude-dependent and User-defined. In the second option, the user specifies the site altitude and can optionally adjust the default, altitude-dependent air temperature. In the third option, the user completely specifies the ambient atmosphere using atmospheric pressure, temperature and relative humidity.

DATA OPTIONS
Type: Complete local data (summary of blast properties at a user-specified distance); shock trajectories (positions vs time); times of shock arrival (vs distance); shock speeds (vs distance); hydrostatic, dynamic and total (stagnation) pressures; flow velocities; air densities; temperatures; sound speeds; entropy changes; energy densities and fluxes, and work (available energy) densities and fluxes. Times of positive phase duration and pressure impulses can be obtained using interpolation and integration options. These data and how they are calculated are described in on-line Help and, in greater detail, the AirBlast User's Guide.
Format: Time histories at user-specified distances from the charge, Peak profiles (peak values vs distance) and Wave profiles (values vs distance at user-specified times). Complete local data are presented in a non-graphical 'report' format.
Units: User data may be input, and results displayed, in either SI (metric) or Imperial (British) units. The units system may be changed at any time.
Normalization: Results may be displayed in 'absolute' units or normalized to ambient atmospheric values. For example, with Normalization 'Off', blast pressures will be displayed in units of either or 'kPa' (SI) or 'psi' (Imperial); with Normalization 'On', those pressures will be divided by the ambient atmospheric pressure and the ratios displayed in 'atmospheres'. Normalization may be switched On and Off at any time.

VIEW OPTIONS
AirBlast installs with an ActiveX component which manages the graphical display of results. Options include linear and logarithmic plots, zooming and colour control, for example. Graphical displays may be printed or saved to disk for inclusion in documents. Using the Numerical View option, data can be exported as text to other applications. Of special interest are the Interpolation and Integration options: The first allows the user to obtain exact data values at specified times and distances and obtain the times and distances at which the data have specific values. The integration option allows the user to obtain information such as pressure impulses and total energies.

FILE OPTIONS
Defined explosive events and data requests can be saved to disk files for later recall. The user can easily write and use Macro command files for tasks containing repetitive actions with small alterations. In addition to Event, Data and Macro files, the user can create a Log file.

SPECIAL OPTIONS
Licensed owners of the EBlast system can also access that program's damage and injury data using the AirBlast interface. A line-mode interface, AirLine, is available by special arrangement for non-Windows systems and resource-restricted systems such as older laptops.