## Abstract

The behavior of two unequal solitary waves during head-on collision was experimentally studied by optical and particle-tracer methods. Spatial surface profiles were measured using the particle mask correlation method and the image thresholding method, which detects the air-water boundary as a set of locally extreme luminance values. The measured surface displacement of the colliding wave was compared with the corresponding shape of a third-order perturbation approximation. In addition, to estimate the phase shift from the crest at an arbitrary point, the instantaneous surface variations were measured by two wave gauges. The kinetic features of the target and the oncoming and colliding waves were measured by a particle image velocimetry method. To solve the phase shift, we acquired the velocity fields of the colliding waves in a series of experiments and could show our technological advantage over others.## References

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