Since an impact of the flow conditions on the RTD was already observed, oscillating flow conditions were evaluated as a strategy to realize narrow residence time distributions by finetuning the stroke frequency and stroke amplitude. Oscillatory flow conditions can be described by a specific Reynolds number, the oscillatory Reynolds number Re0. This Reynolds number and the bulk flow Reynolds number ReN (equation 8 and 9) can be correlated by the velocity ratio Ψ (equation 10).