Roughness implementation and convective heat transfer coefficient computation toward ice accretion simulation

In the simulation of icing, the calculation of the convective heat transfer coefficient for rough surfaces has significant importance. Our study investigates the extension of the γ-Reθt transition model for rough icing surfaces and aims to provide an alternative to the integral boundary layer method for facilitating the calculation of the heat transfer coefficient in three-dimensional icing simulations. Initially, the performance of the γ-Reθt transition model in predicting the transition characteristics and heat transfer for smooth surfaces is examined. Subsequently, to compensate for the deficiency of the γ-Reθt transition model in predicting the premature transition caused by roughness, an additional model equation Ar is introduced to simulate the influence of the surface roughness. Three test cases, including a clean cylinder, an iced cylinder, and a swept wing, are used to validate the applicability of the γ-Reθt-Ar transition model for heat transfer computations on rough surfaces. The results demonstrate that the γ-Reθt-Ar model is superior to other turbulence models in computing convective heat transfer for two-dimensional and three-dimensional icing rough surfaces and shows its potential for ice accretion simulation.