Patent ID: 8481278

Claim:
A method of determining the ability of a fluid variable to modify flow of a fluid, comprising: (a) applying the fluid to a medium comprising converging flow paths, wherein the fluid flows into each of the converging flow paths; (b) measuring the point of convergence of the fluid fronts in the flow paths; and (c) determining a change in the fluid variable that corresponds to modification in the flow of the fluid in one of the flow paths based on a change in the point of convergence of said fluid fronts; wherein: (i) one of the flow paths has been modified such that flow of the fluid in the modified flow path changes in proportion to the change in the fluid variable; (ii) one of the flow paths has not been modified; and (iii) the point of convergence of the fluid fronts in the converging flow paths proportionally corresponds to the change in the fluid variable; and (iv) the fluid variable comprises 1) viscosity of the fluid.