Simulation of the Effects of an Air Blast Wave - ELSA - Europa

parameters of the JWL-equation should represent this limitation (see Shin [21]). Shin shows theinfluence of the discretisation with a 1D model, where a finer mesh reproduces larger pressures.The results with the models explosive1 to explosive4 show the same dependency of the elementsizes (Figure 14). The Chapman-Jouguet-pressure seems to be the limit in the convergence study.2.40E+102.00E+10Pressure [Pa]1.60E+101.20E+108.00E+09t=7e-6t=1.4e-6Shin t=7e-6Shin t=1.4e-5Chapman-Jouguet-pressure4.00E+090.00E+000 200 400 600 800 1000 1200 1400 1600 1800 2000Number of elementsFigure 14: Maximum pressures in the explosive depending on the number of elementsThe rather unexpected behaviour of the models with 499 and 859 elements has to be clarified. Thereason could lie in the location of the detonation point in conjunction with the location of theintegration points.Figure 15 shows the pressure depending on the distance from the initiation point. The curve doesnot differ for models with fine discretisation. It is observed that the pressures behind the pressurepeak in the model explosive6 are definitely smaller than the results of Shin. Therefore, the areaunder the pressure-distance curve is also smaller. This area reaches only 67 % of the area of Shin.The reason could be the missing burn fraction (see chapter 4.1).26