Airfoil performance degradation by coupling effects of supercooled raindrop icing and heavy rainfall

Icing and rainfall are the two critical meteorological factors that threaten the aircraft flight safety. A number of previous studies have shown their individual influences on aircraft aerodynamics; however, to date no studies on their coupling effects exist. In this paper, a numerical study is conducted to focus on the aerodynamic performance of a NACA 23012 airfoil exposed to heavy rain in the presence of an ice accretion by supercooled raindrop on the leading edge. An Eulerian–Lagrangian two-phase flow approach developed for rain simulation in our previous work is adopted here with some improvement in the turbulence model. A series of new phenomena about the aerodynamic performance and wake characteristics under the coupling effects of ice accretion and rainfall are found and discussed. These results do not seem to have been published previously and should be of significance to the aircraft industry for improved aircraft design and pilot training.