Tuesday, August 6, 2013

1308.0653 (Chuandong Lin et al.)

Polar coordinate lattice Boltzmann modeling of detonation phenomena    [PDF]

Chuandong Lin, Aiguo Xu, Guangcai Zhang, Yingjun Li
We present a polar coordinate lattice Boltzmann model for the detonation phenomena. In this model the fluid behavior is describe by a finite-difference lattice Boltzmann(FDLB) model in polar coordinates, and the chemical reaction is described by Cochran's rate function. The released chemical energy is naturally coupled with the flow behavior. We introduce an operator-splitting scheme to both the FDLB equation and Cochran's rate function. The temporal evolutions are calculated analytically and the convection terms are solved via the first-order upwind scheme. The model is validated and verified via comparing simulation results with analytical solution of steady detonation. We simulate the detonation phenomena in two cases: implosion and explosion. Finally, we study some non-equilibrium characteristics in the steady detonation procedure. Numerical results show that, the amplitudes of deviations from thermodynamic equilibrium in front of von-Neumann peak are much higher than those behind the peak. At the von Neumann peak, the system is nearly in its thermodynamic equilibrium. By comparing each component of the high-order moments and its value in equilibrium, we draw qualitative information on the actual distribution functions at the two sides of von-Neumann peak. Such observations are helpful for the physical modeling of detonation phenomena from the macroscopic level.
View original: http://arxiv.org/abs/1308.0653

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