In this paper, we detail a new experimental facility for Refractive Index Matching (RIM) applications based upon the use of low viscosity working fluids (comparable to water) and designed for a wide spectrum of complex flow applications. This facility represents the benchmark for the design of a larger channel for high-Reynolds-number applications. The use of an aqueous solution of sodium iodide (NaI) as the index-matching fluid is explored, with particular focus on the special design features of this model facility compared to standard water channels (corrosion-resistant components, oxygen removal, sloping test section, etc.) and previous RIM facilities. The criteria that guided the choice of the RI-matched solid-fluid combination are discussed together with facility design details and processing procedures for maintaining high quality NaI solution. A series of proof-of-concept experiments was undertaken to assess the quality of refractive index matching achievable, as well as the quality of velocity data attainable via particle image velocimetry. The facility was used to measure the flow around and through a permeable object immersed in a turbulent free-surface flow. The use of optical diagnostics for interrogation of the flow behavior in this configuration is normally not possible due to optical access restrictions but for which RIM produces excellent results.

Original languageEnglish (US)
StatePublished - 2012
Event50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition - Nashville, TN, United States
Duration: Jan 9 2012Jan 12 2012


Other50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition
Country/TerritoryUnited States
CityNashville, TN

ASJC Scopus subject areas

  • Aerospace Engineering


Dive into the research topics of 'A versatile refractive-index-matched flow facility for studies of complex flow systems across scientific disciplines'. Together they form a unique fingerprint.

Cite this