Micro morphological observation and mechanism analysis of boundary layer evolution in mixed powder lubrication

2017 ◽  
Vol 30 (3) ◽  
pp. 91-101
Author(s):  
Chao Wang ◽  
Wei Wang ◽  
Yong Liu ◽  
Kun Liu
Keyword(s):  
Boundary Layer ◽  
Morphological Observation ◽  
Mechanism Analysis ◽  
Mixed Powder ◽  
Powder Lubrication

Investigation of the Secondary Crossflow at the Rectangular Exit of a Low-Speed Sectioned Contractive Wind Tunnel

2020 ◽  
Author(s):  
Shuo Zhang ◽  
Fu Tian ◽  
Xiaofang Wang ◽  
Qiang Gao ◽  
Yongfeng Sui ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Flow Field ◽  
Secondary Flow ◽  
Static Pressure ◽  
Mechanism Analysis ◽  
Low Speed ◽  
Boundary Layer Suction ◽  
Aerodynamic Experiment ◽  
Numerical Approaches

Abstract The low-speed rectangular exit wind tunnel with sectioned contraction is widely used. The secondary flow vortices are found at contraction exit, which would lead to the non-uniform boundary layer and influence the aerodynamic experiment accuracy. In this paper, experimental and numerical approaches are adopted so as to clarify reasons for the formation of the secondary crossflow occurring at contraction exit and take measures to control it. The conclusions can be gotten as: the secondary crossflow is formed and developed in the second (rectangular-to-rectangular) contraction, and the first (circular-to-rectangular) contraction promote the secondary flow vortices to migrate to the middle of flow field to a certain extent; the formation of the secondary crossflow is related to the static pressure gradient in the contraction. Based on the mechanism analysis results, several methods aimed to control the secondary crossflow are proposed and verified, the results can be concluded as: in terms of the rectangular-to-rectangular contraction that contracts along one direction, it is difficult to effectively control the secondary crossflow just by optimizing contraction curves and contraction ratios, while adopting the boundary layer suction can significantly improve the boundary layer uniformity; if the rectangular-to-rectangular contraction contracts in two directions, such secondary crossflow can be well controlled.

Development of 200 kV Scanning-Transmission Electron Microscope

1974 ◽  
Vol 32 ◽  
pp. 410-411
Author(s):  
H. Koike ◽  
S. Sakurai ◽  
K. Ueno ◽  
M. Watanabe
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Transmission Electron Microscope ◽  
The Other ◽  
Morphological Observation ◽  
Magnetic Domains ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Backscattered Electron ◽  
Increasing Demand

In recent years, there has been increasing demand for higher voltage SEMs, in the field of surface observation, especially that of magnetic domains, dislocations, and electron channeling patterns by backscattered electron microscopy. On the other hand, the resolution of the CTEM has now reached 1 ∼ 2Å, and several reports have recently been made on the observation of atom images, indicating that the ultimate goal of morphological observation has beem nearly achieved.

Effects of continental boundary layer evolution, convection, turbulence and entrainment, on aerosol formation

Tellus B ◽  
2001 ◽  
Vol 53 (4) ◽  
pp. 441-461 ◽  
Author(s):  
E. D. NILSSON ◽  
Ü. RANNIK ◽  
M. KULMALA ◽  
G. BUZORIUS ◽  
C. D. O'DOWD
Keyword(s):  
Boundary Layer ◽  
Aerosol Formation

Characteristics of the Night and Day Time Atmospheric Boundary Layer at Dome C, Antarctica

2007 ◽  
Vol 25 ◽  
pp. 49-55 ◽  
Author(s):  
S. Argentini ◽  
I. Pietroni ◽  
G. Mastrantonio ◽  
A. Viola ◽  
S. Zilitinchevich
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Night And Day
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