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Scaling for icing wind tunnel tests andvalidation with numerical simulations

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2019
Özbek Yanmaz, Gizem.
Icing is one of the most dangerous hazards to be encountered by air vehicles in flight. Ice accretion, particularly on control surfaces, wings and flight data sensors usually degrades both performance and operational safety of air vehicles. Thus, it has become important in the design and certification phases of system development to evaluate performance degradation because of icing. Icing wind tunnel testing is the most convenient method considering feasibility, cost and safety. However, when full-size model is too large for a given facility or when the desired test conditions are out of the operating capability of the facility, a scaling method that produces scaled ice accretions over a wide range of test conditions and that can be applied to a variety of icing testing situations is needed. The scaling method shall be validated before the icing wind tunnel testing for reliability and validity of the tests. This work illustrates a scaling method for size scaling and test-condition scaling that is based on similitudes of geometry, flow field, droplet trajectory, water catch, energy balance and surface water dynamics. Icing analyses are performed for full-size and scaled conditions using an in-house icing code AEROMSICE-2D and a CFD tool ANSYS® Fluent 18.0 and in-flight icing code FENSAP-ICE. The ice accretions obtained by analyses are verified with experimental data available in the literature. Furthermore, the scaling method is tested for geometry scaling and velocity scaling at several icing conditions.