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Chip Formation Mechanism of Inconel 718: A Review of Models and Approaches

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Chinese Journal of Mechanical Engineering 2021年第2期34卷 52-67页

作者： Chun Liu Min Wan Weihong Zhang Yun Yang School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China State IJR Center of Aerospace Design and Additive Manufacturing Northwestern Polytechnical UniversityXi’an 710072China

Inconel 718,a nickel,chrome and iron alloy,has special advantages,such as high-temperature strength,thermal resistance and corrosion resistance,which facilitate wide usage in the aerospace industry,especially in the hot sections of gas turbine ***,machining this alloy is correlated closely with the material’s inherent properties such as excellent combination of strength,hardness and toughness,low thermal conductivity and the tendency to adhere to cutting *** nickel alloy also contains inclusions of hard abrasive carbide particles that lead to work-hardening of the workpiece material and thus abrasive wear of the cutting *** is,the machining of Inconel 718 is always influenced by high mechanical and thermal *** article reviews the chip formation mechanism of Inconel *** of the main characteristics in machining of Inconel 718 is that it will produce serrated or segmented chips in a wide range of cutting speeds and *** studies show that the chip serration or segmentation by shear localization affects the machined surface integrity,and also contributes to the chip’s evacuation and the automation of machining ***,research conclusion indicates that the serrated or segmented chip phenomenon is desirable in reducing the level of cutting force,and detailed analysis of models and approaches to understand the chip formation mechanism of Inconel 718 is vital for machining this alloy effectively and ***,this article presents some summaries on the models and approaches on the chip formation in machining of Inconel 718.

关键词： Inconel 718 Chip formation mechanism shear instability Segmented chip

ESTABLISHMENT OF THE OCEAN DYNAMIC SYSTEM WITH FOUR SUB-SYSTEMS AND THE DERIVATION OF THEIR GOVERNING EQUATION SETS

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Journal of Hydrodynamics 2012年第2期24卷 153-168页

作者： YUAN Ye-li QIA0 Fang-li YIN Xun-qiang HAN Lei LU Ming The First Institute of Oceanography State Oceanic Administration of ChinaQingdao 266061China

Based on their differences in physical characteristics and time-space scales,the ocean motions have been divided into four types in the present paper：turbulence,wave-like motion,eddy-like motion and *** the three-fold Reynolds averages to the governing equations with Boussinesq approximation,with the averages defined on the former three sub-systems,we derive the governing equation sets of the four sub-systems and refer to their sum as ＂the ocean dynamic system＂.In these equation sets,the interactions among different motions appear in two forms：the first one includes advection transport and shear instability generation of larger scale motions,and the second one is the mixing induced by smaller scale motions in the form of transport flux *** governing equation sets are the basis of analytical/numerical descriptions of various ocean processes.

关键词： ocean dynamic system four sub-systems advection transport shear instability transport flux residue

The influence of background waves on internal solitary waves after the transit of Typhoon Neast in the northern South China Sea

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Acta Oceanologica Sinica 2014年第12期33卷 40-47页

作者： LIN Feilong HOU Yijun LIU Ze HU Po FANG Yong DUAN Yongliang Institute of Oceanology Chinese Academy of Sciences Key Laboratory of Ocean Circulation and Waves (KLOCAW) Chinese Academy of Sciences University of Chinese Academy of Sciences Center for Ocean and Climate Research First Institute of Oceanography State Oceanic Administration

On the basis of the time series observations from a temperature chain and an acoustic Doppler current profiler on the continental shelf of the northern South China Sea, a sequence of internal solitary waves （ISWs） and background waves （BWs, including internal tides and near-inertial waves） on the continental shelf were captured simultaneously after the transit of Typhoon Neast in October 2011. These measurementsprovided a unique opportunity to explore the influence of BWs on the ISWs. The BWs appeared a conversion on the current strength and vertical mode structure during the observational period. The BWs were dominated by weak and mode-one waves before October 2 and then turned to strong and high-mode waves after that time. Meanwhile, the ISWs displayed different wave structures before and after October 2, which was closely related to BWs＇ changes. According to the current profiles of BWs, the high-mode wave structure with strong current could significantly strengthen the vertical shear of ISWs in the near-surface layer and promote the breaking of ISWs, and thus it may play an important role in affecting the background current condition.

关键词： internal solitary wave shear instability near-inertial waves internal tides

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Linear Stability of Taylor-Couette Flows with Axial Heat Buoyancy

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Chinese Physics Letters 2006年第8期23卷 2135-2138页

作者：陈建国任玲符松 Center for Public Safety Research Tsinghua University Beijing 100084 Department of Engineering Physics Tsinghua University Beijing 100084 Department of Engineering Mechanics Tsinghua University Beijing 100084

The linear stability is studied of flows confined between two concentric cylinders, in which the radial temperature gradient and axial gravity are considered for an incompressible Newtonian fluid. Numerical method based on the Petrov-Galerkin scheme is developed to deal with the buoyancy term in momentum equations and an additional temperature perturbation equation. Computations of the neutral stability curves are performed for different rotation cases. It is found that the flow instability is influenced by both centrifugal and axial shear instabilities, and the two instability mechanisms interact with each other. The outer cylinder rotation plays dual roles of stabilizer and destabilizer under different rotating stages with the inner cylinder at rest. For the heat buoyancyinduced axial flow, spiral structures are found in the instability modes.

关键词： shear instability POISEUILLE FLOW CENTRIFUGAL COMPETITION