A hydrodynamic confined flow device is essentially a flow chamber, where a small volume of fluid is spatially confined within the other, significantly larger fluid volume.
The two miscible or immiscible liquids are physically in contact yet separated by means of a virtual boundary. Mixing between the two zones is largely defined by diffusion.
The experimental conditions necessary to achieve efficient confinement, while inhibiting diffusion across the virtual boundary, are characterized by low Reynolds and high Péclet numbers. The hydrodynamic flow is a continuous steady state flow with minor fluctuations due to the pressure pump feedback control loop that generates a stable and continuous pressure.