Explosions & Combustion

Many terrorist attacks involve the use of explosives. Fluid flow simulation can be used to design barriers and blast deflectors that will mitigate the effect of an explosion. Given the size of a bomb, CFD can predict the path and strength of the blast wave and its reflections, thereby providing the load on the surrounding structures. In the aftermath of an attack, flow simulation can predict the spreading of the debris cloud to yield the local concentrations of harmful particulates. The spreading of the cloud will be affected by the wind and by air currents that arise due to local temperature differences, including local fires. Flow simulation can be used to account for all such factors, and can be used to determine optimum evacuation routes.

FLUENT has a well established reputation for its diverse and reliable combustion models. More recently, FLUENT has the added capability of tracking and resolving traveling blast waves and shocks by means of dynamic adaption. In combination, these tools make it possible to model the initial combustion, and its associated blast wave, to subsequently track that wave, and to determine the pressure load history on nearby objects. This makes it possible to estimate the damage that will result from an explosion, and to devise mechanisms for mitigating the blast damage.

Blast wave resolved using dynamic adaption (extra cells were used where the gradients are highest)
Courtesy of Dan Cler of Benet Laboratories

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Blast wave resulting from a pipe burst in the bleed system of a jetliner

Blast wave from a gun barrel
Courtesy of Dan Cler, Benet Laboratories; postprocessing done in EnSight