Hexagons and spiral defect chaos in non-Boussinesq convection at low Prandtl numbers

Madruga Sánchez, Santiago y Riecke, Hermann (2007). Hexagons and spiral defect chaos in non-Boussinesq convection at low Prandtl numbers. "Physical Review e", v. 75 ; pp.. ISSN 1539-3755. https://doi.org/10.1103/PhysRevE.75.026210.

Descripción

Título: Hexagons and spiral defect chaos in non-Boussinesq convection at low Prandtl numbers
Autor/es:
  • Madruga Sánchez, Santiago
  • Riecke, Hermann
Tipo de Documento: Artículo
Título de Revista/Publicación: Physical Review e
Fecha: 2007
Volumen: 75
Materias:
Escuela: E.T.S.I. Aeronáuticos (UPM) [antigua denominación]
Departamento: Fundamentos Matemáticos de la Tecnología Aeronáutica [hasta 2014]
Licencias Creative Commons: Reconocimiento - Sin obra derivada - No comercial

Texto completo

[img]
Vista Previa
PDF (Document Portable Format) - Se necesita un visor de ficheros PDF, como GSview, Xpdf o Adobe Acrobat Reader
Descargar (1MB) | Vista Previa

Resumen

We study the stability and dynamics of non-Boussinesq convection in pure gases ?CO2 and SF6? with Prandtl numbers near Pr? 1 and in a H2-Xe mixture with Pr= 0.17. Focusing on the strongly nonlinear regime we employ Galerkin stability analyses and direct numerical simulations of the Navier-Stokes equations. For Pr ? 1 and intermediate non-Boussinesq effects we find reentrance of stable hexagons as the Rayleigh number is increased. For stronger non-Boussinesq effects the usual, transverse side-band instability is superseded by a longitudinal side-band instability. Moreover, the hexagons do not exhibit any amplitude instability to rolls. Seemingly, this result contradicts the experimentally observed transition from hexagons to rolls. We resolve this discrepancy by including the effect of the lateral walls. Non-Boussinesq effects modify the spiral defect chaos observed for larger Rayleigh numbers. For convection in SF6 we find that non-Boussinesq effects strongly increase the number of small, compact convection cells and with it enhance the cellular character of the patterns. In H2-Xe, closer to threshold, we find instead an enhanced tendency toward roll-like structures. In both cases the number of spirals and of targetlike components is reduced. We quantify these effects using recently developed diagnostics of the geometric properties of the patterns.

Más información

ID de Registro: 21708
Identificador DC: http://oa.upm.es/21708/
Identificador OAI: oai:oa.upm.es:21708
Identificador DOI: 10.1103/PhysRevE.75.026210
Depositado por: Memoria Investigacion
Depositado el: 11 Mar 2014 16:33
Ultima Modificación: 21 Abr 2016 12:26
  • Open Access
  • Open Access
  • Sherpa-Romeo
    Compruebe si la revista anglosajona en la que ha publicado un artículo permite también su publicación en abierto.
  • Dulcinea
    Compruebe si la revista española en la que ha publicado un artículo permite también su publicación en abierto.
  • Recolecta
  • e-ciencia
  • Observatorio I+D+i UPM
  • OpenCourseWare UPM