[EN] This paper is to present a detailed case study on how the nozzle flow dynamics influences the primary breakup in the spray formation process of diesel injection. The investigation was based on a 3-hole real-application nozzle with highly tapered injection holes using a URANS-LES (Large Eddy Simulation) hybrid approach in combination with the coupled Volume of Fluid (VOF) and Level Set method. High resolution LES was applied to simultaneously resolve the multi-scale nozzle flow dynamics downstream of the needle seat and the primary breakup process in the near-nozzle spray. Phase Contrast X-ray imaging (PCX) was applied to characterize the liquid-gas interfaces in the near-nozzle spray for validation purposes. The results provide detailed information on how the vortex shedding and vortex interactions in the injection hole drives the jet deformation, ligament and droplet formation in the primary breakup process. The FNR funding to the PhD project of Pablo Aguado Lopez (number 588638), the European Union Horizon-2020 Research and Innovation Programme funding to Eduardo Gomez Santos (No 675676), the ANSYS research license grant and the CPU hours grant from Gompute to this work are gratefully acknowledged. The x-ray investigation was carried out using the Advanced Photon Source of the Argonne National Laboratory of US Department of Energy. The kind assistance of the scientist of beam line #32, Dr. Kamel Fezzaa, is highly appreciated by the authors. Shi, J.; Aguado Lopez, P.; Gomez Santos, E.; Guerrassi, N.; Dober, G.; Bauer, W.; Lai, M.... (2017). Evidence of vortex driven primary breakup in high pressure fuel injection. En Ilass Europe. 28th european conference on Liquid Atomization and Spray Systems. Editorial Universitat Politècnica de València. 10-17. https://doi.org/10.4995/ILASS2017.2017.5707