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Studies of transition in taylor-couette flow using hot wire anemometry and on-line computation / S. Benmansour 

Public ISBD Titre : Studies of transition in taylor-couette flow using hot wire anemometry and on-line computation Type de document : texte imprimé Auteurs : S. Benmansour, Auteur ; F. R. Mobbs, Directeur de thèse Editeur : University of Leeds Année de publication : 1984 Importance : 330 f. Présentation : ill. Format : 30 cm. Note générale : Thèse de Doctorat : Mechanical Engineering : Royaume-Uni, University of Leeds : 1984 Bibliogr. f. 331 - 342 . Annexe f. 343 - 379 Langues : Anglais (eng) Index. décimale : D003584 Résumé : The phenomenon of Taylor vortex flow is particularly suitable for the study of hydrodynamic stability and its relationship to transition to turbulence. It is of considerable academic interest as well as occurring in practical engineering situations. Various techniques have been used to investigate the instability and subsequent behaviour of the flow between rotating concentric cylinders. Hot wire anemometry, in conjunction with on-line computation, was employed in the present work to determine the frequencies and wave numbers associated with wavy Taylor vortex flow using spectral analysis, for the case of a stationary outer cylinder and rotating inner cylinder. As the speed of the inner cylinder was gradually increased, the flow was seen to exhibit various complex transitions in the range of Taylor number covered, which was up to 600 Tc. A literature survey showed extensive research into Taylor vortex flow using many different methods of investigation. The results reveal discrepancies in some cases due partly to the many parameters involved and to the different geometry of the rigs used. In the present work, we have assessed the influence of the aspect ratio and radius ratio on the transitions and compared the results with other workers' findings. The experiments were conducted at three positions in the gap, namely 0.18 d, mid.gap and 0.81 d from the inner cylinder. The aspect ratio was varied from 35 to 20 for the two values of radius ratio considered (i.e. n = 0.713 and 0.497). The general trends of the results revealed similar behaviour in terms of frequency bands for the three probe positions in the gap and for all the aspect ratios considered, but wave number changes were the most outstanding feature of the flow which were reflected in relative wave speed changes. The axial wave length was also seen to play an important role in determining the onset of waviness and the value of the wave frequencies. Studies of transition in taylor-couette flow using hot wire anemometry and on-line computation [texte imprimé] / S. Benmansour, Auteur ; F. R. Mobbs, Directeur de thèse . - [S.l.] : University of Leeds, 1984 . - 330 f. : ill. ; 30 cm. Thèse de Doctorat : Mechanical Engineering : Royaume-Uni, University of Leeds : 1984 Bibliogr. f. 331 - 342 . Annexe f. 343 - 379 Langues : Anglais (eng) Index. décimale : D003584 Résumé : The phenomenon of Taylor vortex flow is particularly suitable for the study of hydrodynamic stability and its relationship to transition to turbulence. It is of considerable academic interest as well as occurring in practical engineering situations. Various techniques have been used to investigate the instability and subsequent behaviour of the flow between rotating concentric cylinders. Hot wire anemometry, in conjunction with on-line computation, was employed in the present work to determine the frequencies and wave numbers associated with wavy Taylor vortex flow using spectral analysis, for the case of a stationary outer cylinder and rotating inner cylinder. As the speed of the inner cylinder was gradually increased, the flow was seen to exhibit various complex transitions in the range of Taylor number covered, which was up to 600 Tc. A literature survey showed extensive research into Taylor vortex flow using many different methods of investigation. The results reveal discrepancies in some cases due partly to the many parameters involved and to the different geometry of the rigs used. In the present work, we have assessed the influence of the aspect ratio and radius ratio on the transitions and compared the results with other workers' findings. The experiments were conducted at three positions in the gap, namely 0.18 d, mid.gap and 0.81 d from the inner cylinder. The aspect ratio was varied from 35 to 20 for the two values of radius ratio considered (i.e. n = 0.713 and 0.497). The general trends of the results revealed similar behaviour in terms of frequency bands for the three probe positions in the gap and for all the aspect ratios considered, but wave number changes were the most outstanding feature of the flow which were reflected in relative wave speed changes. The axial wave length was also seen to play an important role in determining the onset of waviness and the value of the wave frequencies.

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