In the present work, the transient pressure driven shear flow of highly concentrated suspensions was investigated. The authors applied a novel Doppler-based ultrasound velocity profiler (Met-Flow SA)–pressure difference (UVP–PD) methodology (Ouriev B 2000 PhD Thesis Zurich ISBN: 3-905609-11-8, Ouriev B and Windhab E 2002 J. Exp. Fluids 32 204–11), for the investigation of concentrated suspensions in steady and transient flows. Model suspensions with two different solid phase concentrations and fluid matrixes were analysed in shear steady flow at different volumetric flow rates. Transient flow was initiated by abrupt flow interruption. Simultaneous recording of the pressure gradient (Windhab E 1986 Thesis VDI) and real time flow velocity profiles enables analyses of transient rheological flow properties. Both velocity and rheological information were simultaneously measured on-line and evaluated off-line. The rheological characteristics of the suspensions in transient flow are compared with those in steady flow and conclusions are drawn.
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