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Niveau: Supérieur, Doctorat, Bac+8

Metastability of solitary roll wave solutions of the St. Venant equations with viscosity Blake Barker? Mathew A. Johnson† L.Miguel Rodrigues‡ Kevin Zumbrun March 9, 2011 Keywords: solitary waves; St. Venant equations; convective instability. 2000 MR Subject Classification: 35B35. Abstract We study by a combination of numerical and analytical Evans function techniques the stability of solitary wave solutions of the St. Venant equations for viscous shallow- water flow down an incline, and related models. Our main result is to exhibit examples of metastable solitary waves for the St. Venant equations, with stable point spectrum indicating coherence of the wave profile but unstable essential spectrum indicating os- cillatory convective instabilities shed in its wake. We propose a mechanism based on “dynamic spectrum” of the wave profile, by which a wave train of solitary pulses can stabilize each other by de-amplification of convective instabilities as they pass through successive waves. We present numerical time evolution studies supporting these con- clusions, which bear also on the possibility of stable periodic solutions close to the homoclinic. For the closely related viscous Jin-Xin model, by contrast, for which the essential spectrum is stable, we show using the stability index of Gardner–Zumbrun that solitary wave pulses are always exponentially unstable, possessing point spectra with positive real part. 1 Introduction Roll waves are a well-known phenomenon occurring in shallow water flow down an inclined ramp, generated by competition between gravitational force and friction along the bottom.

Metastability of solitary roll wave solutions of the St. Venant equations with viscosity Blake Barker? Mathew A. Johnson† L.Miguel Rodrigues‡ Kevin Zumbrun March 9, 2011 Keywords: solitary waves; St. Venant equations; convective instability. 2000 MR Subject Classification: 35B35. Abstract We study by a combination of numerical and analytical Evans function techniques the stability of solitary wave solutions of the St. Venant equations for viscous shallow- water flow down an incline, and related models. Our main result is to exhibit examples of metastable solitary waves for the St. Venant equations, with stable point spectrum indicating coherence of the wave profile but unstable essential spectrum indicating os- cillatory convective instabilities shed in its wake. We propose a mechanism based on “dynamic spectrum” of the wave profile, by which a wave train of solitary pulses can stabilize each other by de-amplification of convective instabilities as they pass through successive waves. We present numerical time evolution studies supporting these con- clusions, which bear also on the possibility of stable periodic solutions close to the homoclinic. For the closely related viscous Jin-Xin model, by contrast, for which the essential spectrum is stable, we show using the stability index of Gardner–Zumbrun that solitary wave pulses are always exponentially unstable, possessing point spectra with positive real part. 1 Introduction Roll waves are a well-known phenomenon occurring in shallow water flow down an inclined ramp, generated by competition between gravitational force and friction along the bottom.

- essential spectrum
- limiting constant
- wave
- waves
- boundary navier–stokes
- solitary
- order scalar
- wave solution
- surfaces tension

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Published by | mijec |

Reads | 31 |

Language | English |

Document size | 4 MB |

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