Investigation of the Blockage Correction to Improve the Accuracy of Taylor's Low-Speed Wind Tunnel

Abstract

Placing a test model in the wind tunnel test section creates an interaction between the flow and the model and walls of the test section. This interaction affects the accuracy of data reading of the wind tunnel. One of the significant factors is the blockage which affects the drag and lift coefficients, causing inaccurate readings. This paper considered streamlined and blunted shapes of different sizes to investigate and assess the effect of the shape and size of the test model on the reading accuracy. Wind tunnel tests were conducted with the three different sizes for each shape to determine the aerodynamic coefficients of the models. Different correction methods were applied to find the correction coefficient. CFD simulations were performed using ANSYS Fluent software. A comparison of numerical and experimental results was carried out to determine the most suitable blockage correction method for the chosen models. It is found that a blockage ratio of less than 16% has the least blockage effect. The blockage correction of drag reduction for these models is very minimal, less than 1%. Correction coefficients for both shapes were derived to correct the blockage effect created by models with a blockage ratio of 16% or higher.