Three-dimensional schlieren measurements using inverse tomography

The ‘‘synthetic schlieren’’ method has been used to measure the amplitude of internal waves that are two-dimensional and axisymmetric. Here it is adapted to reconstruct fully three-dimensional perturbations. This non-intrusive technique, which uses inverse tomography methods, shows accurate results when a sufficient number of perspectives taken from the same experiment are provided to the inversion code. We demonstrate the effectiveness of the wavefield reconstruction from three idealized disturbances in the form of a Gaussian function, a Gaussian multiplied in amplitude by a sine function and a sinusoidal plane wave with an elliptical envelope. The consequences of noisy data input are also investigated.