Fluid flow continuous physical or chemical processes using dean vortices

Method for carrying out a continuous physical or chemical process comprising the steps of:

• i) flowing a fluid through a channel comprising an inlet and an outlet for said fluid, wherein said channel is at least in part curved and comprises at least two curvatures,
• ii) allowing said process to occur at least in part in said fluid in the presence of Dean vortices in said fluid, while
• iii) reversing the direction of the flow of said fluid in said channel multiple times, wherein Dean vortices in the fluid in the channel are maintained while the flow is reversed, and
• repeating step iii) at least once in the continuous process,
• wherein during reversal,
• relaxation time as defined by Tν is greater than reversal time as defined by Tf, both measured in seconds, whereby (fd2/ν)>1,
• f=1/Tf where Tf is a period in seconds where the fluid has a volumetric flow rate of less than 25% of a mean volumetric flow rate of the fluid, and the mean volumetric flow rate is per time period between two reversals of the direction of the flow,
• d is the internal diameter of the channel measured in meters, and
• ν is the kinematic viscosity of the fluid in meters2/second.