Effects of high activation energies on acoustic timescale detonation initiation

Regele, Jonathan D.; Kassoy, D. R.; Vasilyev, Oleg V.

doi:10.1080/13647830.2011.647090

Cited by 20 publications

(21 citation statements)

References 33 publications

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“…This process is similar to that described by a localized thermal power deposition used by Kassoy et al (2008), Kassoy (2010) and Regele, Kassoy & Vasilyev (2012). The weaker the inertial confinement of the initial reaction wave, the longer the initial detonation takes to form.…”

Section: Physical Parametersmentioning

confidence: 83%

Verified and validated calculation of unsteady dynamics of viscous hydrogen–air detonations

2015

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The dynamics of one-dimensional, piston-driven hydrogen-air detonations are predicted in the presence of physical mass, momentum and energy diffusion. The calculations are automatically verified by the use of an adaptive wavelet-based computational method which correlates a user-specified error tolerance to the error in the calculations. The predicted frequency of 0.97 MHz for an overdriven pulsating detonation agrees well with the 1.04 MHz frequency observed by Lehr in a shock-induced combustion experiment around a spherical projectile, thus giving a limited validation for the model. A study is performed in which the supporting piston velocity is varied, and the long time behaviour is examined for an initially stoichiometric mixture at 293.15 K and 1 atm. Several distinct propagation behaviours are predicted: a stable detonation, a high-frequency pulsating detonation, a pulsating detonation with two competing modes, a low-frequency pulsating detonation and a propagating detonation with many active frequencies. In the low-frequency pulsating mode, the long time behaviour undergoes a phenomenon similar to period-doubling. Harmonic analysis is used to examine how the frequency of the pulsations evolves as the supporting piston velocity is varied. It is found that the addition of viscosity shifts the neutral stability boundary by about 2 % with respect to the supporting piston velocity. As the supporting piston velocity is lowered, the intrinsic instability grows in strength, and the effect of viscosity is weakened such that the results are indistinguishable from the inviscid predictions.

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Section: Physical Parametersmentioning

confidence: 83%

Verified and validated calculation of unsteady dynamics of viscous hydrogen–air detonations

2015

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“…Adaptive Wavelet Collocation Method (AWCM) is such a technique, which has been developed and thoroughly investigated for parabolic [1,2], hyperbolic [3], and elliptic [4] partial differential equations. It was successfully applied to a wide spectrum of problems including incompressible [5], compressible subsonic [6] and supersonic [3] flows, wavelet-based Adaptive Large Eddy Simulation [7,8,9,10,11,12,13], thermoacoustic wave propagation [14], Rayleigh-Taylor instability [15], ocean modeling [16], combustion [17], fluid-structure interactions [18,19], viscoelastic and poroviscoelastic flows [20,21,22].…”

Section: Introductionmentioning

confidence: 99%

Parallel adaptive wavelet collocation method for PDEs

Nejadmalayeri¹,

Vezolainen

Brown-Dymkoski

et al. 2015

Journal of Computational Physics

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Please cite this article in press as: A. Nejadmalayeri et al., Parallel adaptive wavelet collocation method for PDEs, J. Comput. Phys. (2015), http://dx. AbstractA parallel adaptive wavelet collocation method for solving a large class of Partial Differential Equations is presented. The parallelization is achieved by developing an asynchronous parallel wavelet transform, which allows one to perform parallel wavelet transform and derivative calculations with only one data synchronization at the highest level of resolution. The data are stored using tree-like structure with tree roots starting at a priori defined level of resolution. Both static and dynamic domain partitioning approaches are developed. For the dynamic domain partitioning, trees are considered to be the minimum quanta of data to be migrated between the processes. This allows fully automated and efficient handling of non-simply connected partitioning of a computational domain. Dynamic load balancing is achieved via domain repartitioning during the grid adaptation step and reassigning trees to the appropriate processes to ensure approximately the same number of grid points on each process. The parallel efficiency of the approach is discussed based on parallel adaptive wavelet-based Coherent Vortex Simulations of homogenous turbulence with linear forcing at effective non-adaptive resolutions up to 2048 3 using as many as 2048 CPU cores.

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“…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.…”

Section: Introductionmentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Regele

Kassoy

Vezolainen

et al. 2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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A "purely gasdynamic" indirect detonation initiation process is presented that can be independent of diffusion, viscosity and turbulence, and does not require direct initiation. In this process, energy is deposited into a finite volume of fluid in an amount of time that is similar to the acoustic timescale of the fluid volume. Highly resolved two-dimensional simulations show that the artificial diffusion implicit in the numerical method is demonstrated to accelerate detonation formation. It is shown that given sufficient resolution, the detonation formation time becomes dependent only on large-scale gasdynamics and is independent of the small scale structures.

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Effects of high activation energies on acoustic timescale detonation initiation

Cited by 20 publications

References 33 publications

Verified and validated calculation of unsteady dynamics of viscous hydrogen–air detonations

Verified and validated calculation of unsteady dynamics of viscous hydrogen–air detonations

Parallel adaptive wavelet collocation method for PDEs

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

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