MICROGEOMETRIC PARAMETERS OF SURFACES IN MODELING LARGE-SCALE AERODYNAMIC DIGITAL EXPERIMENTS

Abstract

This article explores the micro-geometric parameters of surfaces within the framework of modeling large-scale aerodynamic digital experiments in order to improve the accuracy of reproducing the interaction of air flows with solid surfaces. Special attention is paid to the role of roughness, formed by microscopic irregularities, as an object of micro-geometry research and its influence on the distribution of aerodynamic flows near the walls of the wind tunnel and the surface of the sub-model, as well as the resulting viscous stresses and wall friction. The article includes a comparative analysis of two approaches to defining flow conditions for the interaction with solid surfaces in CFD-modeling programs: the “no-slip” condition and the “free-slip” condition. Computer experiments show that the use of the “free-slip” condition for the airflow in the near-wall region provides more realistic results reflecting the occurrence of gradients, wave disturbances, and velocity decay patterns in the working region of a small-scale wind tunnel, compared to the “no-slip” condition. The findings of this study highlight the importance of selecting the correct boundary conditions and surface parameters for creating accurate digital twins of complex technical systems, including aerodynamic ones.