Numerical Investigation of Discontinuous Ice Effects on Swept Wings

TL;DR

This study uses advanced simulations to analyze how discontinuous ice on swept wings affects aerodynamics, revealing more severe lift reduction and unique flow patterns compared to continuous ice.

Contribution

It introduces a detailed flow analysis of discontinuous ice effects on swept wings, highlighting differences from continuous ice and identifying characteristic vortex shedding patterns.

Findings

Discontinuous ice causes greater lift loss than continuous ice.

Flow over discontinuous ice features irregular shear layers and specific vortex shedding frequencies.

Lift and drag fluctuations are mainly linked to vortex shedding at St = 22.6.

Abstract

This study investigates the aerodynamic performance and flow structures of infinite swept wings with artificially simulated discontinuous ice using an enhanced delayed detached-eddy simulation. Comparisons are made among clean, continuous-ice, and discontinuous-ice configurations. Results show that discontinuous ice causes a more severe reduction in lift than continuous ice. While continuous ice forms a large separation bubble that helps maintain lift, discontinuous ice disrupts leading-edge vortex formation through gap jets, resulting in greater lift loss but a smaller drag penalty. Unlike the continuous-ice wing, the discontinuous-ice case does not exhibit a sudden stall-induced lift drop. The flow over the discontinuous-ice wing can be characterized by two canonical patterns: a separating shear layer and K\'arm\'an vortex shedding. However, the separating shear layer becomes irregular due to the interference of gap jets. Three characteristic chord-based Strouhal numbers (St)-11.3, 22.6, and 33.9-are identified. The lowest (St=11.3) corresponds to the shedding of vortex pairs; when nondimensionalized by the ice width, it yields St = 0.58, which is higher than that of a canonical cylinder wake. Furthermore, lift and drag fluctuations occur predominantly at St = 22.6, twice the shedding frequency, primarily induced by the gap jets-a phenomenon absent in the continuous-ice case.