English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

The problem of detonation attenuation in stoichiometric methane-oxygen andits re-establishment following its interaction with obstacles was investigatedusing high resolution numerical simulation. The main focus was on the role ofthe transverse detonation on the re-establishment of the detonation wave. Weapplied an efficient thermochemically derived four-step global combustion modelusing an Euler simulation framework to investigate the critical regimespresent. While past attempts at using one- or two- step models have failed tocapture transverse detonations, for this scenario, our simulations havedemonstrated that the four-step combustion model is able to capture thisfeature. We suggest that to correctly model detonation re-initiation incharacteristically unstable mixtures, an applied combustion model shouldcontain at least an adequate description to permit the correct ignition andstate variable response when changes in temperature and pressure occur. Oursimulations reveal that there is a relationship between the critical outcomespossible and the mixture cell size, and while pockets of unburned gas may existwhen a detonation re-initiates, it is not the direct rapid consumption of thesepockets that gives rise to transverse detonations. Instead, the transversedetonations are initiated through pressure amplification of reaction zones atburned/unburned gas interfaces whose combustion rates have been enhancedthrough Richmyer-Meshkov instabilities associated with the passing oftransverse shock waves, or by spontaneous ignition of hot spots, which can forminto detonations through the Zel'dovich gradient mechanism. In both situations,non-uniform ignition delay times are found to play a role. Finally, we foundthat the transverse detonations are in fact Chapman-Jouguet detonations, butwhose presence contributes to overdriving the re-initiated detonation along theMach stem.

On the role of transverse detonation waves in the re-establishment of attenuated detonations in methane-oxygen