A validated design methodology for a closed-loop subsonic wind tunnel

A systematic investigation into the design and simulation of flow parameters in a closed-loop wind tunnel was carried out using Computational Fluid Dynamics (CFD). The analytical model for estimating pressure losses were directed as input boundary conditions. Full-scale model of the entire wind tunnel was considered instead of the conventional approach, in which only test section flow is simulated. This allowed for optimisation of flow quality not only in the test section but also the flow in the entire circuit. Analysis of the guide vane configurations showed that test section flow quality was more affected by flow conditions in upstream than downstream sections. Hence, special attention must be given while designing the vanes at upstream turns particularly corners in line with the test section. Validation of the test section with block model showed that CFD was able to replicate wind tunnel measurements of velocity, turbulence intensity and pressure coefficient with error below 10%.