Numerical Simulation of Aerodynamic Features with Ice Shapes via High-Fidelity CFD Method

In this chapter, the unsteady aerodynamic features of ice-contaminated flow are studied via a high-fidelity numerical method. A review of previous computational studies is first introduced with a particular focus on the classification of the flow features with different ice shapes. To obtain a high-fidelity database, a low-dissipation compressible Navier-Stokes solver is employed to model the unsteadiness with sufficient spatial and temporal resolution. Verification and validation are presented with different meshes, turbulence models, and numerical orders of accuracy. The studies compare the aerodynamic features of different ice shapes including horn ice and spanwise ridge ice, with which a more in-depth analysis of unsteady flow characteristics is mainly carried out around one of the ice types. The predictions with a set of instantaneous and statistical coefficients are evaluated at different angles of attack, Reynolds, and Mach conditions. The high-resolute phenomena of eddy dynamics such as vortex pairing, shedding, breaking down, and rolling up are further discussed. Proper orthogonal decomposition (POD) and dynamic modal decomposition (DMD) are then used to analyze the effect of vortex shedding and the evolution of dominant modes with varying input conditions and their instability frequencies. The effect of flow fluctuations from high to low frequency is then related to typical coherent structures.