Abstract Test duration in gun tunnels is on the order of several milliseconds, so its extension is crucial for easier and more accurate experimental measurement. However, there is a lack of reported work on the physical mechanisms governing the test time in gun tunnels. To address this issue, this paper explored the influence of the length of the driver section (L4), the driven section (L1), and the pressure ratio (P4/P1) between the driver and the driven section on the test time of gun tunnels through numerical simulations. It is found that the starting point of test time is related to the moment of the 4th shock wave arrival, and the end point corresponds to the event of piston or expansion wave arrival, depending on which one happens first. Furthermore, in order to obtain the maximum test time for a gun tunnel, the ratios of the length and the pressure between the driver and the driven section need to be adjusted so that the piston and the expansion waves can arrive at the end of the driven tube simultaneously. When L4/L1 and P4/P1 is larger than the optimal value, the piston reaches the end of the driven tube faster than the expansion waves. This is because the velocity of the piston is higher while that of the expansion waves is basically unchanged at larger P4/P1. In addition, the distance for the expansion waves to travel is longer at bigger L4. On the contrary, when L4/L1 and P4/P1 is smaller than the optimum, the expansion waves hit the end of the driven section before the piston.


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    Title :

    Physical mechanism for extending the test time in gun tunnels


    Contributors:
    Zeng, Wei (author) / Ma, Haiteng (author)


    Publication date :

    2024-01-23




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English




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