DID YOU KNOW? DTIC has over 3.5 million final reports on DoD funded research, development, test, and evaluation activities available to our registered users. Click HERE
to register or log in.
High Resolution WENO Simulation of 3D Detonation Waves
BROWN UNIV PROVIDENCE RI DIV OF APPLIED MATHEMATICS
Pagination or Media Count:
In this paper, we develop a three-dimensional parallel solver using the fifth order high-resolution weighted essentially non-oscillatory WENO finite difference scheme to perform extensive simulation for three-dimensional gaseous detonations. A careful study is conducted for the propagation modes of the three-dimensional gaseous detonation wave-front structure in a long square duct with different widths under different initial perturbations. The numerical results indicate that, with a transverse sinusoidal perturbation of the initial ZND profile, when the width of the duct is less than the cellular width 4.5xL12, unstable detonations can trigger a spinning motion in the duct. The detonation wave propagates in a single-headed spinning motion, with a distinctive ribbon displayed on the four walls. In this case, the measured pitch-to-diameter ratio is approximately 3.42, which is slightly larger than the theoretically predicted value 3.128 for a round duct. When the channel width is greater than the cellular width, detonation waves propagate in an out-of-phase rectangular mode. With a transverse cosine perturbation of the initial ZND profile, the front of the stable detonation has a rectangular structure, and regular cellular patterns and in-phase slapping waves can be observed clearly on the four walls. The width-to-length ratio of the cellular patterns is approximately 0.5. For a mildly unstable detonation, its front has an in-phase rectangular structure at the early stage, then the wave-front becomes flat. Over time, but it still maintains an in-phase rectangular structure after reigniting. For highly unstable detonations, the wave-front has a rectangular structure at the early stage. After a low pressure stage for a very long time, detonation occurs once again. At this time, the detonation front structure becomes very twisted, and the triple-lines become asymmetrical. Finally, a spinning detonation mode is triggered.
APPROVED FOR PUBLIC RELEASE