Optical investigation of dense suspensions with non-Newtonian matrix under pulsating pumping

Pressure-driven Poiseuille flow of a bidisperse, non-colloidal, dense granular suspension with non-Newtonian matrix under pulsatile pumping is studied experimentally. The flow properties are recorded using a transmitted light optical system. The setup allows to derive velocity profiles with a high spatial and temporal resolution. Statements can be made about the near-wall region, which are difficult to achieve experimentally in dense suspensions. The results are compared in detail with velocity profiles based on theoretical models from the field of suspension rheology and particle migration under the conditions present in the experiment. •Spatially and temporally resolved velocity profiles of a pulsating pipe flow.•Complete comparison of experimental data with rheological and particle migration models.•Determination of wall slip coefficients and comparison with predictions of theoretical models.•Evaluation of velocity profiles during acceleration and deceleration phases (pulsating pumping).•Investigation of different particle distributions with regard to the evolving velocity profiles and wall slip.