Quasi-periodic large-scale vortex structure in bod bundle lattice with micro ribs

Quasi-periodic large-scale vortex structure (QLVS) is highly accounted for the local flow and heat transfer and turbulent mixing in rod bundles. The vortex structures between rod bundles with different rib heights are analyzed, and the morphology of QLVS is clarified. The mechanism of the QLVS is studied from the perspective of hydrodynamics, and the formation and development process of the QLVS are analyzed in detail. Combined with the criterion of QLVS, the rotation, deformation and velocity changes of small disturbance are analyzed. With the increase of the height of the micro-rib, QLVS is introduced and gradually enhanced. The velocity gradient be-tween different fluid layers is a key factor in the formation and development of QLVS structures. This research can provide theoretical support for the design and optimization of rod bundle lattices.