## 1 Introduction  
Ice accretion on the nacelle lip-skin surface which occur upon flying through clouds containing super cooled water droplets (SWD) can result in a reduction or a loss of aerodynamic performance due to the formation of non-aerodynamic profile [1; 2]. When this occurs, the fuel consumption increases due to the higher drag force, and the thrust reduces as a consequence of the restriction of airflow through the fan due to ice accumulated on the inner surface portion of the nacelle lip-skin [3]. The worst scenario occurs when broken ice particles are absorbed, the ingestion of which can critically damage the engine. For these reasons, protection against icing is required as it is a potential cause of aircraft crashes. A typical anti-icing system used for the nacelle is the piccolo tube anti-icing (PTAI), which is one of the most popular hot-bleed-air anti-icing devices utilized for wings, among others [4; 5; 6]. The parameters affecting the thermal performance of the PTAI include the hot air mass flow rate, jet spacing, the distance from the holes to the surface, the impingement angle, etc. [7]. This high-performance system is better than other ice protection systems with respect to efficiency and reliability; nevertheless, it has limitations in terms of performance losses, energy costs, complexity, weight, and hotspot issues [8]. Furthermore, the engine nacelle is mainly exposed to the icing environment with SWD during the takeoff and the initial climb phases of flight [1; 9]. According to the Federal Aviation Administration regulation, the anti-icing systems cannot be activated until the aircraft reaches \(400\) feet above the takeoff surface to avoid engine thrust reduction [10]. Therefore, the PTAI cannot protect the nacelle against ice accretion during these two flight phases. Therefore, it could be highly desirable, mainly in these two flight phases, to use a passive ice protection system (IPS) such as a superhydrophobic coating (SHC) which is able to reduce the droplets permanence on the surface nacelle lip-skin, thereby reducing de facto the accreted ice [11]. Additionally, during the whole flight, the passive SHC could be used in combination with the active PTAI to reduce the needed hot air mass flow, and consequently mitigate some limitations of the active PTAI system, such as the increased fuel consumption, the reduced overall thermal efficiency, and the performance losses. Several previous studies focused on the simulation study of the effect of PTAI on the lip-skin of the nacelle [3; 8; 9; 12; 13; 14], but very little can be found in the literature with regard to the experimental tests in icing wind tunnel (IWT). For example, [PERSON] [15] conducted icing tests in the NASA Glenn wind tunnel for a full-sized engine inlet and documented ice shapes on the leading edge under different icing conditions. [PERSON] et al. [16] conducted an experimental campaign to study the dynamic ice accretion on rotating aeroengine spinner and fan blades, with the aim to evaluate the icing-induced performance degradation to the fan rotor. With the perspective to reduce the energy cost of the PTAI system, in [17], the authors carried out an experimental study to quantify the dynamic ice accretion process on aeroengine inlet guide vanes in order to optimize the design paradigms to reduce the requirements of the bleed air. Finally, they also suggested as a novel anti-/ de-icing strategy to leverage hydrophobic/icephobic coatings to further reduce the requirements of the bleed air for the inlet guide vanes' anti-/ de-icing operation, thereby minimizing the performance penalties to the aeroengines. Studies on the effect of a superhydrophobic surface (SHS) and anti-icing coatings on rotating aeroengine fan blades were reported in [18], where the authors highlighted that both SHS and icephobic coatings have advantages in anti-icing.