Effect of Initial Disturbance on The Detonation Front Structure of a Narrow Duct

TL;DR

This study uses high-resolution 3D simulations to investigate how initial disturbances influence the structure and stability of detonation fronts in narrow ducts, revealing that spinning detonations are the most stable outcome.

Contribution

It demonstrates how different initial disturbances affect detonation front evolution, establishing spinning detonation as the most stable mode in narrow ducts.

Findings

Random disturbances lead to stable spinning detonations.

Symmetrical disturbances initially form diagonal patterns that break down.

Spinning detonation is the most stable mode in narrow ducts.

Abstract

The effect of an initial disturbance on the detonation front structure in a narrow duct is studied by three-dimensional numerical simulation. The numerical method used includes a high resolution fifth-order weighted essentially non-oscillatory scheme for spatial discretization, coupled with a third order total variation diminishing Runge-Kutta time stepping method. Two types of disturbances are used for the initial perturbation. One is a random disturbance which is imposed on the whole area of the detonation front, and the other is a symmetrical disturbance imposed within a band along the diagonal direction on the front. The results show that the two types of disturbances lead to different processes. For the random disturbance, the detonation front evolves into a stable spinning detonation. For the symmetrical diagonal disturbance, the detonation front displays a diagonal pattern at an early stage, but this pattern is unstable. It breaks down after a short while and it finally evolves into a spinning detonation. The spinning detonation structure ultimately formed due to the two types of disturbances is the same. This means that spinning detonation is the most stable mode for the simulated narrow duct. Therefore, in a narrow duct, triggering a spinning detonation can be an effective way to produce a stable detonation as well as to speed up the deflagration to detonation transition process.