Numerical Evaluation of the Flow Quality of a Large-Scale Low-Speed Wind Tunnel via Steady CFD Simulation

This study presents a full-scale steady CFD methodology for evaluating flow quality in a large-scale low-speed wind tunnel (8 m × 6 m test section, 130 m/s). The tunnel geometry is resolved at 1:1 scale, the damping screens and honeycomb are modeled as porous media, and results are validated against wind tunnel test data and the GJB 1179A-2012 acceptance criteria. The baseline configuration reproduces the axial static pressure gradient within the acceptance criterion but substantially overpredicts turbulence intensity, dynamic pressure coefficient, and both velocity direction deviation angles. Damping screens, modeled as porous jumps, provide the dominant correction, bringing all metrics within the acceptance limits. Adding honeycomb yields incremental improvement: porous zone modeling preserves or improves all metrics, whereas a porous jump representation pushes velocity direction deviations beyond the limit. Between RNG k-ε and SST k-ω, only turbulence intensity is closure-dependent, with RNG k-ε closer to experiment. At Ma ≈ 0.38, compressibility does not alter the flow quality assessment, confirming that incompressible assumption is sufficient. By replacing costly physical trials with a validated CFD workflow, these findings provide a practical, resource-efficient reference for the CFD-based evaluation, design, and retrofit of wind tunnel infrastructure that underpins renewable-energy and energy-efficiency research.