Investigation of Thermal Convection Over Realistic Ice Roughness Under Flow Acceleration using ELES

This study employs Embedded Large Eddy Simulation (ELES) to analyze favorable pressure gradient (FPG) effects on convective heat transfer from realistic roughness based on laser-scanned, unwrapped airfoil ice shapes. A progressively increasing pressure gradient is introduced by a systematic variation of the domain upper shape to mimic the effect of a wind-tunnel ceiling insert. Skin friction (cf) and Stanton number (St) trends are analyzed, as well as turbulent flow properties, to assess the effect of various FPG configurations on convection with reference to the zero-pressure gradient (ZPG) one. Flow acceleration shows a primary impact only on the pressure component of cf, while no visible effect on scaled St distribution is detected, suggesting that FPG might add-up to local pressure gradient introduced by roughness resulting in further breakdown of the Reynolds analogy. The analysis confirms that ELES accurately resolves the joint effects of ice roughness and pressure gradients on aerodynamic and thermal behavior, delivering insights into friction and heat transfer and exploring the usage of a simplified flat-plate configuration as a reliable surrogate for complex airfoil geometries.