Numerical simulations of the structure and propagation of self-sustained detonations

Two-dimensional time-dependent numerical simulations have been performed to determine a computational method of determining the natural cell size of a self-sustained detonation. The systematic approach developed involves simulating systems with tube heights both larger and smaller than the transverse cell spacing. This approach, tested on a mixture of hydrogen, oxygen and argon, provided us with an estimate of the cell size which is in excellent agreement with experimental observations. The simulations also provided insight into some aspects of the mechanism by which a self-sustained detonation propagates. The evolution of the curvature of the transverse wave appears to be the crucial feature. Depending on the curvature of the transverse wave at the time of its reflections from either a neighboring transverse wave or a wall, the cell is either flattened or pockets of unreacted gas can be formed.