The work to be undertaken in the area of atmospheric and spray icing of structures consists primarily of experimental studies conducted within the framework of parallel analytical studies. The main objective is to develop improved predictors of loading (icing weight, aerodynamic drag and lift) associated with icings, and formulation of collection efficiency, and freezing fractions, n. Two sets of experiments will be conducted using the Iowa Institute of Hydraulic Research (IIHR) Icing Wind Tunnel. The first set will consist of measurements of icing accretion rates, icing forms, and structural loadings due to major icing types (glaze, and hard and soft rime). The second set of experiments will focus attention on: the dynamics of droplet trajectory through, and deposition from the local flow field around a structural element undergoing icing; and the heat transfer processes associated with icing accretion. These measurements and the analysis of the obtained data will help in improving the understanding and formulation E and n. State-of-the-art force transducers and measurement, and flow- visualization instrumentation will he used in carrying out this work. The pioneering use of laser-sheet and holographic methods for image- processing will be an important contribution to droplet trajectories and deposition measurements. The P.I. is highly qualified to perform this research and the facilities at his disposal are among the best in the world. An award for two years is recommended with the proviso that a third year of support can be granted only upon the presentation of a satisfactory report on findings together with an updated workplan.
