IIMAS - FENOMEC
UNAM
Viscous hyperstabilization of detonation waves
Resumen:
It has long been a standard practice to neglect diffusive effects in stability analyses of detonation waves. In this talk, I will describe recent work aimed at quantifying the impact of these oft-neglected effects on the stability characteristics of such waves. In particular, I will discuss the use of numerical Evans-function techniques to study the (spectral) stability of viscous strong detonation waves---particular traveling-wave solutions of the Navier--Stokes equations modeling a mixture of reacting gases. Remarkably, the results show a surprising synergy between the high-activation-energy limit typically studied in stability analyses of detonation waves and the presence of small but nonzero diffusive effects. While the calculations do show a modest delay in the onset of instability in agreement with recently reported calculations by direct numerical simulation of the physical equations, the Evans-function approach also provides additional spectral information. In particular, for each of the families of detonation waves in our computational domain, the computations show a completely unexpected kind of hysteresis in the limit of increasing activation energy; that is, the computations suggest that, whenever diffusive effects are present, there is a return to stability as unstable eigenvalues return to the stable complex half plane. This is joint work with Blake Barker (Indiana), Jeffrey Humpherys (Brigham Young), and Kevin Zumbrun (Indiana).
Informes: coloquiomym@gmail.com, o al 5622-3564.