Ice-Induced Separation Bubble on RG-15 Airfoil at Low Reynolds Number
Nay Oo, P. Richards, Rajnish N. Sharma
Abstract
Large-eddy simulation (LES) of an RG-15 airfoil in clean (that is, nonturbulent) flow is conducted at a Reynolds number of with and without the formation of ice on its leading edge. The characteristics of the ice-induced separation bubble (ISB) and its influence on the aerodynamic performance are studied at low angles of attack (, 3, and 6 deg). These are compared to the naturally developed laminar separation bubble (LSB) on the corresponding clean (that is, noniced) airfoil. As expected, the LSB on the clean airfoil contracts in size and travels toward the leading edge with an increase in AOA. In contrast, the ISB on the iced airfoil grows in size with an increase in AOA, albeit marginally, as the location of the reattachment moves downstream. The characteristics of the boundary-layer separation, transition, and turbulence after reattachment are similar for both the ISB and LSB. Furthermore, it is noted that the streamwise ice accretion increases the lift coefficient at a 0 deg AOA, whereas the drag remains almost unchanged.