About the Refractive Index Matched Facility (FoRMS Lab)
The FoRMS Lab enables high-resolution optical measurements with minimal distortion by matching the refractive index of the fluid to that of the transparent materials used to construct experimental models and the facility. This provides optical access to the flow around complex geometries while minimising refraction, shadowing and reflection effects.
The facilities use an aqueous sodium iodide (NaI) solution, with its refractive index controlled through temperature and concentration. The laboratory is equipped with degassing and temperature-control systems to maintain fluid clarity and provide precise control of the experimental conditions. The NaI solution is approximately twice as dense as water, enabling Reynolds numbers comparable to, or slightly higher than, those achievable in equivalent water-channel facilities.
The lab consists of two independent facilities, with different test-section sizes and flow capabilities to support a wide range of experimental investigations.
