Uncertainty Quantification of the Drag Reduction Effect of Superhydrophobic Structure Spacing through Direct Numerical Simulation with Nek5000/NekRS.*

The drag reduction technologies have been investigated and show promise for preventing global warming by reducing energy consumption. One representative technology is the superhydrophobic surface (SHS). SHS structures are classified into two types: ridge (longitudinal groove) type and post type^[1]. The hydrodynamic features of SHS vary depending on the type. Consequently, recent research has focused separately on ridge types^[2] and post types^[3]. In this study, the drag reduction effect of SHS was quantified irrespective of the SHS type. By utilizing uncertainty quantification (UQ) and direct numerical simulation (DNS), the effects of different SHS types were investigated. The streamwise and spanwise distances between the solid posts were treated as random input variables, assumed to follow a Gaussian distribution. The mean values(μ₁, μ₂) of each input variables were 20μm and the standard deviation(σ₁, σ₂) were 0.33μ.