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Bibliographic Details
Main Authors: Luk, Jonathan, Speck, Jared
Format: Preprint
Published: 2021
Subjects:
Online Access:https://arxiv.org/abs/2107.03426
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Table of Contents:
  • Consider a $1$D simple small-amplitude solution $(ρ_{(bkg)}, v^1_{(bkg)})$ to the isentropic compressible Euler equations which has smooth initial data, coincides with a constant state outside a compact set, and forms a shock in finite time. Viewing $(ρ_{(bkg)}, v^1_{(bkg)})$ as a plane-symmetric solution to the full compressible Euler equations in $3$D, we prove that the shock-formation mechanism for the solution $(ρ_{(bkg)}, v^1_{(bkg)})$ is stable against all sufficiently small and compactly supported perturbations. In particular, these perturbations are allowed to break the symmetry and have non-trivial vorticity and variable entropy. Our approach reveals the full structure of the set of blowup-points at the first singular time: within the constant-time hypersurface of first blowup, the solution's first-order Cartesian coordinate partial derivatives blow up precisely on the zero level set of a function that measures the inverse foliation density of a family of characteristic hypersurfaces. Moreover, relative to a set of geometric coordinates constructed out of an acoustic eikonal function, the fluid solution and the inverse foliation density function remain smooth up to the shock; the blowup of the solution's Cartesian coordinate partial derivatives is caused by a degeneracy between the geometric and Cartesian coordinates, signified by the vanishing of the inverse foliation density (i.e., the intersection of the characteristics).