Progress Toward a Multidimensional Representation of Mortar Interior Ballistics

Report No. ARL-TR-4839
Authors: John R. Schmidt; Michael J. Nusca
Date/Pages: June 2009; 38 pages
Abstract: Lumped-parameter interior ballistics (IB) codes have had limited success in simulating the IB of mortars due to the complex nature of the firing event. Only near the end of the firing event does the mortar conform to the conventional ballistics model for which lumped-parameter codes were designed.
Modified lumped-parameter models are capable of simulating some key mortar variables. There are significant pressure waves developed in mortars, which are due in part to the nonuniform discharge of combustion products from the flashtube. The mortar IB cycle is not only time dependant but is also very spatially complex. These pressure waves cannot be adequately represented in a one-dimensional IB model.
Plans to modify the Army's two- or three-dimensional IB code ARL-NGEN3 for mortar simulations are discussed. However, conventional NGEN modeling approaches cannot capture the nonuniform discharge of combustion products from the flashtube as shown in experiments. An improvement in gas generation tables and work on a two-phase turbulence model of a primer and black powder pellets with a velocity profile based on the one-dimensional turbulence modeling approach are presented. Plans for coupling this primer model to the ARL-NGEN3 code for mortars are discussed.
Distribution: Approved for public release
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Last Update / Reviewed: June 1, 2009