Viscosity Measurement Using Optical Tracking of Free Fall in Newtonian Fluid |

N. Kheloufi
^{a,b} and M. Lounis^{b,c}^{a}Laboratoire de Géodésie Spatiale, Centre des Techniques Spatiales, BP 13 rue de Palestine Arzew 31200 Oran, Algeria
^{b}Laboratoire LAAR - Faculté de Physique, Département de Technologie des Materiaux, Université des Sciences et de la Technologie d'Oran USTO-MB, BP 1505, El M'Naouer 31000 Oran, Algeria
^{c}Faculté des Sciences et de la Technologie, Université de Khemis Miliana - UKM, Route de Theniet El Had 44225 Khemis Miliana, Algeria |

Received: July 1, 2014; Revised version: April 6, 2015; In final form: May 6, 2015 |

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This paper presents a novel method in viscosity assessment using a tracking of the ball moving in Newtonian fluid. The movement of the ball is assimilated to a free fall within a tube containing liquid of whose we want to measure a viscosity. In classical measurement, height of fall is estimated directly by footage where accuracy is not really considered. Falling ball viscometers have shown, on the one hand, a limit in the ball falling height measuring, on the other hand, a limit in the accuracy estimation of velocity and therefore a weak precision on the viscosity calculation of the fluids. Our technique consist to measure the fall height by taking video sequences of the ball during its fall and thus estimate its terminal velocity which is an important parameter for cinematic velocity computing, using the Stokes formalism. The time of fall is estimated by cumulating time laps between successive video sequences which mean that we can finally estimate the cinematic viscosity of the studied fluid. |

DOI: 10.12693/APhysPolA.128.123 PACS numbers: 83.85.Jn, 83.60.Fg |