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Heat transport in rotating processes finds a wide range of application in which academic issues in the fluid mechanics and heat transfer areas are here reported. This paper discusses successive works from the seminal paper of Taylor (1923) to recent numerical results established from a broad range of methods such as DNS, LES, RANS or LB methods. The flow regimes identification is thus reported in Taylor–Couette geometry. The role of the axial flow rates in the apparition, stabilization and destruction of the large-scale of the turbulent structures is depicted in the case of Taylor–Couette–Poiseuille geometry. In a non-isothermal condition, a discussion is held on the various exponent values found in the scaling relationships relying on the Nusselt number as a function of the Rayleigh or Reynolds numbers according to the regimes of thermal convection. [ABSTRACT FROM AUTHOR]

With the increasing application of bidirectional axial pump, it is necessary to study the flow and cavitation characteristics of bidirectional pump. In this paper, the cavitation and flow characteristics of the tip clearance under different clearances and different cavitation numbers of the S-hydrofoil bidirectional axial flow pump were studied by combining experimental and numerical simulation methods under reverse operation conditions. The section of the bidirectional pump was experimentally studied by high-speed photography and pressure pulsation. Based on the method of RANS, the SST-CC turbulence model and ZGB cavitation model were used to simulate the clearance cavitation of the bidirectional pump, and the cavitation morphology, velocity distribution, clearance vortex structure and energy distribution of blade tip clearance were investigated. The study reveals the flow characteristics of the clearance flow field of the bidirectional pump, and provides reference for the design and operation of it. • Deep cavitation bidirectional pump gap tail will form reverse shear cavitation. • Special distribution of S-shaped hydrofoil gap velocity will form a variety of vortices. • More disorderly flow field at the tail of the bidirectional pump gap. [ABSTRACT FROM AUTHOR]

Studies on the tip leakage vortex (TLV) are extensive, while studies on the secondary tip leakage vortex (S-TLV) are rare. To advance the understanding of the formation mechanism of the S-TLV, turbulent cavitating flows were numerically investigated using the shear stress transport (SST) turbulence model and the Zwart–Gerber–Belamri cavitation model. The morphology and physical quantity distribution of the S-TLV under two cavitation conditions were compared, and its formation mechanism was analyzed. The results reveal that in the lower cavitation number case, there is a low-velocity zone of circumferential flow near the tip in the back half of the blade. The shear vortices formed by the leakage jet gradually accumulate and concentrate in the low-velocity area, which is one of the main sources of the S-TLV. Meanwhile, the radial jet pushes the vortices on the suction surface to the tip, which mixes with the S-TLV. The flow path formed by the radial jet and the leakage jet is in accordance with the rotation direction of the S-TLV, which promotes the S-TLV's further development. Under the conditions of a small cavitation number and low flow rate, the circumferential velocity and radial velocity of the fluid near the gap have altered significantly, which is conducive to the formation of the S-TLV. [ABSTRACT FROM AUTHOR]