Fatma Yahi - Academia.edu (original) (raw)
Teacher -researcher at M'Hamed Bougara University Boumerdes-Algeriaspecelized in the hydrodynamic rotating systems (cones - cylinders and sphers), Interested also by the magnetohydrodynamic.
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Papers by Fatma Yahi
Journal of Applied Fluid Mechanics, Nov 1, 2016
The aim of this work is to highlight the critical thresholds corresponding to the onset of differ... more The aim of this work is to highlight the critical thresholds corresponding to the onset of different instabilities considered in the flow between two vertical coaxial cones with and without free surface. The inner cone is rotating and the outer one is maintained at rest. Both cones have the same apex angle Φ =12° giving a constant annular gap δ =d/R1max. The height of the fluid column is H=155mm and It can be progressively decreased for each studied case of the flow system. Two kinds of configurations are studied, small and large gap. The working fluid is assumed as Newtonian and having constant properties like density and viscosity within the range of the required experimental conditions. By means of visualization technique of the flow we have been able to show the different transition modes occurring in the conical flow system according to the aspect ratio and then the induced action of the free surface which introduces a delay in the onset of different instability modes. The obtained results in term of features and stability of the flow are compared to those of Wimmer and Noui-Mehidi.
EPJ Web of Conferences
The present work is intended to experimentally study the Taylor-Couette flow between coaxial cone... more The present work is intended to experimentally study the Taylor-Couette flow between coaxial cones. The inner cone is rotated and the outer cone is maintained fixed. Both cones have the same apex angle ĭ =12°, giving a constant annular gap į =0.12. The height of the fluid column is H=155 mm. The working fluid is assumed as Newtonian and has constant properties (as density and viscosity) within the range of the required experimental conditions. By means of visualization techniques, the critical thresholds related to the onset of various instabilities have been obtained and the corresponding flow modes have been identified. Using images processing, spatio-temporal diagrams have also been calculated, showing the characteristics (wavelength, drift velocity) of the downward helical motion. The results obtained for these transition regimes are compared to those of Wimmer et al. [1-3].
Journal of Applied Fluid Mechanics, Nov 1, 2016
The aim of this work is to highlight the critical thresholds corresponding to the onset of differ... more The aim of this work is to highlight the critical thresholds corresponding to the onset of different instabilities considered in the flow between two vertical coaxial cones with and without free surface. The inner cone is rotating and the outer one is maintained at rest. Both cones have the same apex angle Φ =12° giving a constant annular gap δ =d/R1max. The height of the fluid column is H=155mm and It can be progressively decreased for each studied case of the flow system. Two kinds of configurations are studied, small and large gap. The working fluid is assumed as Newtonian and having constant properties like density and viscosity within the range of the required experimental conditions. By means of visualization technique of the flow we have been able to show the different transition modes occurring in the conical flow system according to the aspect ratio and then the induced action of the free surface which introduces a delay in the onset of different instability modes. The obtained results in term of features and stability of the flow are compared to those of Wimmer and Noui-Mehidi.
EPJ Web of Conferences
The present work is intended to experimentally study the Taylor-Couette flow between coaxial cone... more The present work is intended to experimentally study the Taylor-Couette flow between coaxial cones. The inner cone is rotated and the outer cone is maintained fixed. Both cones have the same apex angle ĭ =12°, giving a constant annular gap į =0.12. The height of the fluid column is H=155 mm. The working fluid is assumed as Newtonian and has constant properties (as density and viscosity) within the range of the required experimental conditions. By means of visualization techniques, the critical thresholds related to the onset of various instabilities have been obtained and the corresponding flow modes have been identified. Using images processing, spatio-temporal diagrams have also been calculated, showing the characteristics (wavelength, drift velocity) of the downward helical motion. The results obtained for these transition regimes are compared to those of Wimmer et al. [1-3].