Deflection tomographic reconstruction of a complex flow field from incomplete projection data

Tomographic techniques are used for the investigation of complex flow fields by means of deflectometric methods. In this experiment, a modified algebraic reconstruction technique (ART) was applied to moiré deflection tomography. The algorithm was derived from the basic deflection formula and the deflection angles were used directly in iteration, which is completely different from the conventional ARTs with integral calculation that are commonly used in deflection tomography. A smoothing scheme was employed to improve the reconstruction under ill-posed conditions. The reconstruction technique was tested using simulated data for incompleteness conditions similar to those found in the experimental data. The complex density field with an opaque object in a supersonic wind tunnel was reconstructed from limited view angle projections, and the experimental reconstruction was then compared with the result obtained from the computational fluid dynamic analysis. The following paper details the experiment and discusses some measurement errors that occurred in the process.