Tomographic Reconstruction of Hypersonic Aircraft Flowfields in Large-Scale Wind Tunnel Experiments

Abstract

Three-dimensional flowfield features around a hypersonic aircraft model were reconstructed using a computed tomography background-oriented schlieren technique. Datasets of projection images were acquired in hypersonic wind tunnel experiments conducted at the Japan Aerospace Exploration Agency’s 0.5m hypersonic wind tunnel facility, by rotating the test model with an increment of 2° azimuth. A telecentric optical configuration was applied to the background-oriented schlieren measurement at the large-scale hypersonic wind tunnel facility. A basic tomographic reconstruction method, such as filtered backprojection, was used to reconstruct the projection datasets with some combination of denoising calculations. Results showed that the reconstructed flowfield was first noisy without denoising. With the denoising considerations proposed in this study, the flow physics, such as oblique shock waves emanating from the vehicle nose tip and engine lip, were clearly visualized. Therefore, the telecentric optical setup and denoising processes proposed in this study can successfully reconstruct a complex three-dimensional flowfield obtained at a large-scale wind tunnel facility. This setup and denoising process can also apply to other applications in large-scale wind tunnel experiments.