Recent Improvements in Dstl’s capacity for modelling UNDEX and associated structural response

The ever-increasing threat from underwater munitions has warranted the requirement for the ability to numerically simulate underwater explosions and the associated structural response. For many years Dstl has been using APOLLO Blastsimulator, a high-fidelity computational fluid dynamics (CFD) code developed for prediction of blast, for air blast simulations and has since worked to include functionality for underwater explosions, a capability that is still under development. To aid this, emphasis has been placed on attempting to understand the behaviour of non-ideal explosives typically used in this domain through experimental testing in various regimes. The cost implications of large-scale tests underwater, however, have meant that a combination of airblast and small-scale underwater tank tests have been carried out in order to validate modelling capability and provide confidence for upscaling; whilst models are showing promise the software is still under development.