Before revision: In the context of flow visualization a triple decomposition of the velocity gradient  was proposed by Kolat in 2007 who demonstrated the technique in two dimensions, which was later realized in three dimensions by Nagata et al. in 2020.
After revision: In the context of flow visualization a triple decomposition of the velocity gradient was proposed by Kolat in 2007 V. Kolar, International journal of heat and fluid flow, 28, 638, (2007)