A novel circular jet flow characteristics of an unconfined low-Reynolds-number binary-mixture

2011 ◽  
Author(s):  
An-Kuo Hsu ◽  
Kai-Long Hsiao
Keyword(s):  
Reynolds Number ◽  
Binary Mixture ◽  
Low Reynolds Number ◽  
Flow Characteristics ◽  
Jet Flow ◽  
Low Reynolds

Comparative Investigation of Laminar Separation Bubble on a Wing at Low Reynolds Number

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
M.P. Uthra ◽  
A. Daniel Antony
Keyword(s):  
Reynolds Number ◽  
Separation Bubble ◽  
Low Reynolds Number ◽  
Flow Characteristics ◽  
Suction Side ◽  
Aerodynamic Performance ◽  
Laminar Separation Bubble ◽  
Laminar Separation ◽  
Low Reynolds ◽  
Air Vehicles

Most admirable and least known features of low Reynolds number flyers are their aerodynamics. Due to the advancements in low Reynolds number applications such as Micro Air vehicles (MAV), Unmanned Air Vehicles (UAV) and wind turbines, researchers’ concentrates on Low Reynolds number aerodynamics and its effect on aerodynamic performance. The Laminar Separation Bubble (LSB) plays a deteriorating role in affecting the aerodynamic performance of the wings. The parametric study has been performed to analyse the flow around cambered, uncambered wings with different chord and Reynolds number in order to understand the better flow characteristics, LSB and three dimensional flow structures. The computational results are compared with experimental results to show the exact location of LSB. The presence of LSB in all cases is evident and it also affects the aerodynamic characteristics of the wing. There is a strong formation of vortex in the suction side of the wing which impacts the LSB and transition. The vortex structures impact on the LSB is more and it also increases the strength of the LSB throughout the span wise direction.

Flow Characteristics of a Low Reynolds Number Jet in Crossflow with an Obstacle Block

2016 ◽  
Vol 9 (1) ◽  
pp. 37-46 ◽  
Author(s):  
Jianlong Chang ◽  
Xudong Shao ◽  
Xiao Hu ◽  
Shuangbiao Zhang
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Velocity Ratio ◽  
Flow Characteristics ◽  
Vortex Pair ◽  
Lower Velocity ◽  
Eddy Simulation ◽  
Jet In Crossflow ◽  
Crossflow Velocity ◽  
Low Reynolds

The jet in crossflow at very low Reynolds number (Re=100) with and without block is performed by means of large eddy simulation for the jet-to-crossflow velocity ratios (r) ranging from 1 to 3, and the corresponding flow characteristics are compared. The results show that the time-averaged particle trajectories of the jet are slightly changed if a block is presented, and the mixed vortices are weakened. The existence of the block also can accelerate the formation of stable counter-rotating vortex pair. At lower velocity ratio (r=1), the block has little effect on the jet in crossflow with a symmetrically positive and negative kidney shaped vortices. As the velocity ratio increases, the effect of block not only can generate an asymmetry of positive and negative kidney shaped vortices, but also it can reinforce the interaction between the positive and negative vortices in the jet in crossflow. The effect of block on the temperature field is also analyzed in detail.

scholarly journals Tip leakage flow analysis of an axial turbine under the effect of separation at low Reynolds number

2019 ◽  
Vol 234 (6) ◽  
pp. 751-765
Author(s):  
Ziyi Shao ◽  
Wen Li ◽  
Yangli Zhu ◽  
Xing Wang ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Flow Characteristics ◽  
Flow Patterns ◽  
Tip Clearance ◽  
Leakage Flow ◽  
Tip Clearance Flow ◽  
Tip Leakage ◽  
Clearance Flow ◽  
Low Reynolds

The tip clearance flow could lead to work reduction and loss generation in turbomachines. However, the effect of separation at low Reynolds number on leakage flow is seldom studied. The previous method for evaluating tip leakage characteristics should also be further researched. Thus, numerical investigations on the tip clearance flow in an unshrouded axial-inflow turbine are conducted at low Reynolds number (3.5 × 104 of the rotor outlet at the designed condition) in the present study. The flow patterns and leakage mass flow rate of the clearance have been analyzed in detail. It is found that the tip clearance flow is greatly affected by the flow separation caused by low Reynolds number. The scraping ratio adopted in previous references does not accord with the clearance flow characteristics at low Reynolds number, especially in the front part of the clearance. A coefficient by −0.70 power of the Reynolds number is proposed to modify the scraping ratio in the present study. The synergy between the velocity and the pressure gradient is innovatively employed to research the tip clearance flow characteristics, and it gives a reliable criterion of indicating the flow patterns in the tip clearance.

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