G512 Study on Dividing Flow through T-Junction of Rectangular Cross-Section in Low Reynolds Number

2012 ◽  
Vol 2012 (0) ◽  
pp. 523-524
Author(s):  
Takayuki KANEKO ◽  
Masatoshi SANO
Keyword(s):  
Reynolds Number ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Low Reynolds Number ◽  
Flow Through ◽  
Low Reynolds

scholarly journals Numerical Simulation Studies on Stall Suppression of a NACA0015 Airfoil

2021 ◽  
Vol 6 ◽  
pp. 23-31
Author(s):  
Biswash Shrestha ◽  
Nawraj Bhattarai
Keyword(s):  
Reynolds Number ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Constant Width ◽  
Low Reynolds Number ◽  
Lift Coefficient ◽  
Leading Edge ◽  
Ansys Fluent ◽  
Control Plate ◽  
Low Reynolds

This study aims to achieve an improved airfoil performance at low Reynolds number, and to determine the optimum position and size of rectangular cross-section burst control plate (BCP) to suppress stall in airfoil. The type of airfoil used in the present study is NACA0015 (National Advisory Committee for Aeronautics) airfoil with 200 mm of chord (c) length. Here, rectangular cross-section burst control plates with different sizes and at different locations are investigated numerically at the low Reynolds number of 1.6×105. Total of three positions (0.05c, 0.1c and 0.2c from the leading edge of airfoil), and four sizes (with heights 0.3 mm, 0.7mm, 1mm and 1.5 mm, and constant width 4 mm) of rectangular BCPs are simulated in ANSYS Fluent software using Transition SST model. The results indicate that the rectangular cross-section burst control plate is an effective device in the suppression of airfoil stall. For 0.7 mm and 1 mm height BCPs, the stall angle is postponed by 2° for all positions, while for 0.3 mm and 1.5 mm height BCPs, the reduction in sudden fall of lift can be observed but at the cost of reduction in maximum lift coefficient. Among various configurations, the 1mm height BCP located at 0.2c position is found to be most effective in the suppression of stall.

Modeling the f and j Characteristics for Transverse Flow Through an Offset Strip Fin at Low Reynolds Number

2001 ◽  
Vol 8 (4) ◽  
pp. 243-259 ◽  
Author(s):  
Yuri S. Muzychka ◽  
Milan Michael Yovanovich
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Transverse Flow ◽  
Flow Through ◽  
Low Reynolds ◽  
Offset Strip Fin

Reconsideration of low Reynolds number flow-through constriction microchannels using the DSMC method

2005 ◽  
Vol 14 (4) ◽  
pp. 847-856 ◽  
Author(s):  
A.A. Alexeenko ◽  
S.F. Gimelshein ◽  
D.A. Levin
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Dsmc Method ◽  
Low Reynolds Number Flow ◽  
Reynolds Number Flow ◽  
Number Flow ◽  
Flow Through ◽  
Low Reynolds

3D Flow Dynamics in a Patterned Round Microchannel

2009 ◽  
Author(s):  
Huihe Qiu ◽  
Peng Zhang
Keyword(s):  
Reynolds Number ◽  
Surface Modification ◽  
Flow Pattern ◽  
Cross Section ◽  
Low Reynolds Number ◽  
The Other ◽  
Surface Charges ◽  
Patterned Surface ◽  
Zeta Potentials ◽  
Low Reynolds

The development of MEMS requires deliberate designs for controlling fluids in the low Reynolds number regime. Arranging surface charges in rectangular channels to obtain in-plane or out-of-plane vortices have been studied by previous researchers. However, previous surface modification techniques require different signs of zeta potentials from the other wall surfaces which made it difficult in selecting and coating microchannels. Previously, the opposite polarities are usually adjusted by changing the pH value of the solution with acid chemicals in other researches which made the solution complicated and difficult to simulate a real application. Meanwhile the acid chemicals may also destroy the coating. It is convenient to use same polarity patches if a vortex flow can also be generated. However, it is not clear if the patterned surface charges have the same polarity of zeta potentials as the other walls, what kind flow pattern will be generated and what mechanism behind the flow pattern. Furthermore, the cross-section of previously studied microchannels is usually limited to a rectangular shape. Therefore, the surface charge patterns are usually in 2D since the sidewalls of the rectangular microchannels are difficult to be patterned. However, a channel with round cross-section has better leak-proof performance of the membrane valve. Furthermore, a round channel is also advantageous in mimicking the human vein when a vascular structure is needed in tissue scaffolding, the round microfluidic channel is considered as a good candidate for an artificial capillary vessel. It is anticipated that there will be no stagnation occurs at the corner edges, which occurs at the corners of a rectangular channel, for a round microchannel owing to the perfectly symmetrical velocity profile. This is important when the microfluidic chip is subjected to a separation process such as liquid chromatography. In this paper, effects of patterned surface modification on 3D vortex flows generation in a micro capillary tube under very low Reynolds number have been investigated. Microfabrication technology was successfully employed to pattern surface charges on inner surfaces of round capillary tubes, which form non-uniform zeta-potentials. This technique extends the heterogeneous surfaces from flat surface to curved surface. 3D vortices are visualized and measured at the vicinity of tube walls when an electric field is applied across the surfaces utilizing micro resolution PIV. It demonstrated that 3D vortices can also be generated by the patterned surface charges with a same polarity. Experimental results have been compared with the numerical simulations using CFD-ACE+.

Streamwise and Spanwise Flow Structures Over Backward Facing Step in Low Reynolds Number

2006 ◽  
Author(s):  
Shunsuke Yamada ◽  
Tatsuya Matsumoto ◽  
Takashi Nagumo ◽  
Shinji Honami
Keyword(s):  
Reynolds Number ◽  
Cross Section ◽  
Low Reynolds Number ◽  
Spanwise Direction ◽  
Streamwise Direction ◽  
Low Reynolds Number Flow ◽  
Reynolds Number Flow ◽  
Number Flow ◽  
The Cross ◽  
Low Reynolds

A study on the low Reynolds number flow such as the flow in or around the micro device is strongly required along with the development of the micro manufacturing technology. The low Reynolds number flow over a backward facing step is selected as one of the representative examples of the vortex dominant flows in the present study, because the mixing promotion is expected by an oscillatory motion of the vortex in the separating and reattaching shear layer over the step. It is important to clarify the flow fields in small channel or around the small device by flow visualization, since minimum disturbance in the measurement is achieved due to non-intrusive method. The objective of the present study is to clarify the flow behavior in the cross section in the spanwise, transverse and streamwise direction by the flow visualization using a high speed video camera. The Reynolds number based on the step height and the bulk velocity is set at 380 to 960. The visualization results in the cross section in the spanwise direction show that the separating shear layer from the step edge introduces a series of the primary vortices which have a rotation axis around the spanwise direction, and the main stream has a regularly whipping, wavy motion caused by the vortices moving toward the downstream direction along the upper and lower walls. The observation in the cross section in the transverse direction indicates that a scale of the vortex length in the streamwise direction is almost constant, but the primary vortex shows a periodic change in the spanwise direction, as the Reynolds number increases.

Low Reynolds number steady state flow through a branching network of rigid vessels: II. A finite element mixture model

Biorheology ◽  
1989 ◽  
Vol 26 (1) ◽  
pp. 73-84 ◽  
Author(s):  
Jacques M. Huyghe ◽  
Cees W. Oomens ◽  
Dick H. van Campen
Keyword(s):  
Reynolds Number ◽  
Finite Element ◽  
Steady State ◽  
Mixture Model ◽  
Low Reynolds Number ◽  
Steady State Flow ◽  
State Flow ◽  
Flow Through ◽  
Low Reynolds
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