Refractive-index-matched hydrogel materials for modeling flow-structure interactions

摘要

In imaging-based studies of flow around solid objects, it is useful to havematerials that are refractive-index-matched to the surrounding fluid. However,materials currently in use are usually rigid and matched to liquids that areeither expensive or highly viscous. This does not allow for measurements athigh Reynolds number, nor accurate modeling of flexible structures. This workexplores the use of two hydrogels (agarose and polyacrylamide) asrefractive-index-matched models in water. These hydrogels are inexpensive, canbe cast into desired shapes, and have flexibility that can be tuned to matchbiological materials. The use of water as the fluid phase allows this method tobe implemented immediately in many experimental facilities and permitsinvestigation of high Reynolds number phenomena. We explain fabrication methodsand present a summary of the physical and optical properties of both gels, andthen show measurements demonstrating the use of hydrogel models in quantitativeimaging.