Performance Optimization of a Subsonic Wind Tunnel Using Multiple Screens in the Contraction Cone

This experimental study aims to optimize the airflow quality in a subsonic wind tunnel test section by systematically evaluating the effect of installing multiple fine-mesh screens at the contraction cone inlet. Four configurations were tested: a baseline setup with no screen, followed by arrangements with one, two, and three screens. The performance of each arrangement was analyzed using airflow velocity measurements to assess flow consistency and smoke flow visualization to qualitatively characterize turbulence structure and flow uniformity. Results showed a strong link between the number of screens and improved flow. The baseline setup had turbulent and uneven airflow but adding screens steadily enhanced stability. Using three screens gave the most uniform and parallel airflow, confirming this configuration best reduces turbulence for accurate aerodynamics experiments. The investigation reveals that turbulence intensity decreases progressively with increasing screen numbers, with the triple-screen configuration achieving optimal performance at 0.9% ± 0.07% - representing a 71.9% improvement over the baseline configuration. Flow visualization analyses confirm that additional screens effectively break down large-scale turbulent structures while promoting laminar-like flow characteristics with parallel streamlines.