PROPERTIES OF THE IODINE MOLECULE RELEVANT TO LASER-INDUCED FLUORESCENCE EXPERIMENTS IN GAS-FLOWS

Laser-induced fluorescence of iodine seed molecules can be used for both flow visualization and accurate measurements of gasdynamic properties. This paper gives an introductory review of the use of iodine in experimental fluid mechanics, including basic formulas for saturated and non-saturated fluorescence (excited with narrowband or broadband lasers), line shape, line strength and quenching behavior. Techniques for the seeding of the molecules into the gas flow and the safe handling of the gas are discussed. Finally, a simple numerical example is given for the calculation of absorption and fluorescence signals with discussion of the measurement of gasdynamic properties. © 1990 Springer-Verlag.