Detonation initiation on the microsecond time scale: DDTs

Purely Gasdynamic Multidimensional Indirect Detonation Initiation Using Localized Acoustic Timescale Power Deposition

“…Before performing numerical simulations of "purely gasdynamic" acoustic timescale detonation initiation in two dimensions and analyzing the solution sensitivity to numerical resolution, it is helpful to first look at the numerical sensitivity of a previously performed one-dimensional simulation. 10,11 In this work, Case 1 in Ref. 11 is performed at multiple levels of resolution.…”

“…Obviously, the creation of additional longitudinal compression waves through transverse wave refraction inside the reacted fluid medium is a mechanism not present in the previous 1-D work. 10,11,23 The transverse waves compress and heat previously unreacted fuel pockets, which ignite and help produce additional longitudinal waves, as well as sustaining the transverse waves the reverberate off the top and bottom walls. Kelvin-Helmholtz roll-up instabilities are clearly visible in frames t = [10,12,14] at the burnt-unburnt gas interface with a fairly high level of detail.…”

“…10,11,23 The transverse waves compress and heat previously unreacted fuel pockets, which ignite and help produce additional longitudinal waves, as well as sustaining the transverse waves the reverberate off the top and bottom walls. Kelvin-Helmholtz roll-up instabilities are clearly visible in frames t = [10,12,14] at the burnt-unburnt gas interface with a fairly high level of detail. The existence of such a detailed interface serves as an indicator that any numerical diffusion present in the algorithm has been minimized to the point that these features are possible to capture.…”

“…Previous work in this area has focused on 1-D simulations of the reactive Euler equations. 8,9,10,11 The simulations begin with a reactive mixture initially at rest and spatially resolved thermal power addition is imparted to the fluid over a timescale t h ∼ t a . Shock waves are created from the initial power deposition, but unlike direct detonation initiation, the reaction front becomes fully decoupled from the initial shock wave.…”

“…8,9 Heat was later added directly to a fluid volume. 10 Recently the work was extended to higher activation energies 11 and demonstrated a multiple hot-spot behavior typical of high activation energy mixtures.…”