Ferrofluid measurements of bottom velocities and shear stresses  

作　　者：MUSUMECI Rosaria E. MARLETTA Vincenzo ANDò Bruno BAGLIO Salvatore FOTI Enrico 

机构地区：[1]Department of Civil Engineering and Architecture, University of Catania [2]Department of Electric, Electronic and Computer Science Engineering, University of Catania

出　　处：《Journal of Hydrodynamics》2015年第1期150-158,共9页水动力学研究与进展B辑（英文版）

基　　金：funded by the EC project HYDRALAB IV (Contract No. 261520);by the PRIN 2010-2011 project HYDROCAR;by the PON 2007-2013 project SEAPORT funded by MIUR (Italy)

摘　　要：A novel direct measurement strategy of bottom velocities and shear stresses based on the use of ferrofluids is presented. Such a strategy overcomes some of the limits of state-of-the-art instruments. A preliminary experimental campaign has been carried out in the presence of currents in steady flow conditions in order to test the effects of ferrofluid quantity and of the controlling permanent magnetic force. An alternating current （AC） circuit and a direct current （DC） conditioning circuit have been tested. For velocities larger than 0.05 m/s, the near-bottom velocity-output voltage calibration curve has a monotone parabolic shape. The sensitivity of the instrument is increased by a factor of 30 when the DC circuit is used.A novel direct measurement strategy of bottom velocities and shear stresses based on the use of ferrofluids is presented. Such a strategy overcomes some of the limits of state-of-the-art instruments. A preliminary experimental campaign has been carried out in the presence of currents in steady flow conditions in order to test the effects of ferrofluid quantity and of the controlling permanent magnetic force. An alternating current （AC） circuit and a direct current （DC） conditioning circuit have been tested. For velocities larger than 0.05 m/s, the near-bottom velocity-output voltage calibration curve has a monotone parabolic shape. The sensitivity of the instrument is increased by a factor of 30 when the DC circuit is used.

关 键 词：magnetofluids Rosensweig effect flow resistances bed shear stresses bottom velocities 

分 类 号：O361.3[理学—流体力学]