Non-contact acoustic trapping in circular cross-section glass capillaries: A numerical study

2012 ◽  
Vol 132 (5) ◽  
pp. 2978-2987 ◽  
Author(s):  
Ian Gralinski ◽  
Tuncay Alan ◽  
Adrian Neild
Keyword(s):  
Cross Section ◽  
Numerical Study ◽  
Circular Cross Section ◽  
Glass Capillaries

Numerical Study of Incomplete Stent Apposition Caused by Deploying Undersized Stent in Arteries With Elliptical Cross Sections

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Bo Jiang ◽  
Vikas Thondapu ◽  
Eric K. W. Poon ◽  
Peter Barlis ◽  
Andrew S. H. Ooi
Keyword(s):  
Shear Rate ◽  
Cross Section ◽  
Cross Sections ◽  
Numerical Study ◽  
Circular Cross Section ◽  
Blood Stream ◽  
Cfd Simulations ◽  
Elliptical Cross ◽  
Incomplete Stent Apposition ◽  
Computational Fluid Dynamics Cfd

Incomplete stent apposition (ISA) is one of the causes leading to poststent complications, which can be found when an undersized or an underexpanded stent is deployed at lesions. The previous research efforts have focused on ISA in idealized coronary arterial geometry with circular cross section. However, arterial cross section eccentricity plays an important role in both location and severity of ISA. Computational fluid dynamics (CFD) simulations are carried out to systematically study the effects of ISA in arteries with elliptical cross section, as such stents are partially embedded on the minor axis sides of the ellipse and malapposed elsewhere. Overall, ISA leads to high time-averaged wall shear stress (TAWSS) at the proximal end of the stent and low TAWSS at the ISA transition region and the distal end. Shear rate depends on both malapposition distance and blood stream locations, which is found to be significantly higher at the inner stent surface than the outer surface. The proximal high shear rate signifies increasing possibility in platelet activation, when coupled with low TAWSS at the transition and distal regions which may indicate a nidus for in-stent thrombosis.

Numerical Investigation of Turbulent Magnetic Nanofluid Flow inside Straight Channels

2016 ◽  
Vol 819 ◽  
pp. 382-391 ◽  
Author(s):  
Nor Azwadi Che Sidik ◽  
Mohammed Raad Abdulwahab
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Cross Section ◽  
Volume Fraction ◽  
Numerical Study ◽  
Circular Cross Section ◽  
Average Diameter ◽  
Turbulent Regime ◽  
Reynolds Number Increase ◽  
Number Increase

A numerical study using computational fluid dynamics method with an approach of single phase has been presented in order to determine the effects of the concentration of the nanoparticles and flow rate on the convective heat transfer and friction factor in turbulent regime flowing through three different straight channels (straight, circular and triangular) with different Reynolds number (5000 ≤ Re ≤ 20000) using constant applied heat flux. The nanofluid was used consist of Fe3O4 magnetic nanoparticles with average diameter of (13nm) dispersed in water with four volume fraction (0, 0.2, 0.4, 0.6%). The results revealed that as volume fraction and Reynolds number increase Nusselt number increase and the heat transfer rate in circular cross section tube is better than that in square and triangular cross section channels.

Fabrication of sandwich-like microfluidic chip with circular cross-section micro-channels

2018 ◽  
Vol 32 (26) ◽  
pp. 1850288 ◽  
Author(s):  
Hong Cheng Wang ◽  
Miao Miao Zhao ◽  
Li Qun Wu
Keyword(s):  
Cross Section ◽  
Microfluidic Chip ◽  
Low Cost ◽  
Circular Cross Section ◽  
Middle Layer ◽  
Channel Cross Section ◽  
Heating Process ◽  
Micro Channel ◽  
Micro Channels ◽  
Glass Capillaries

In microfluidic chips, most micro-channel cross-section shapes are rectangular or triangular in existing chip fabricating technologies, including hot embossing, lithography, etching, injection molding, etc. However, compared with the above micro-channel shapes, a circular shape has advantages in aspects of fluid flow, droplet generation, heat transfer and blood vessel replication. This paper presents a sandwich-like microfluidic chip with circular cross-section micro-channels. The sandwich-like structure includes three layers. The top and bottom layers are PDMS material while the middle layer is composed of micron glass capillaries (used as micro-channels) with circular cross-sections. The glass capillaries are made of borosilicate tube by a glass heating process. Sphere shaped paraffin wax is used as a sacrificial material to form micro-channel junctions. To test the functions of the fabricated micro sandwich-like microfluidic chip, a droplet generating experiment was conducted in the T-junction chip. The droplet size can be controlled in the range of 20–400 [Formula: see text]m by varying the water and oil flow rates. This proposed microfluidic chip structure has the advantages of short processing cycle, low cost and small flow resistance.

Experimental and Numerical Study of Double Containment Joint Having Circular Cross-Section Support

2011 ◽  
Vol 287-290 ◽  
pp. 2360-2363
Author(s):  
Ali M. Al Samhan
Keyword(s):  
Numerical Analysis ◽  
Cross Section ◽  
Numerical Study ◽  
Circular Cross Section ◽  
Experimental Results ◽  
Set Up

Bonded structure are commonly of three types, purely adhesive bonded, weld-bonded and adhesive/mechanical structures. Present work concern with experimental set-up of double containment joint with circular cross-section support using photoelasticity techniques. The experimental results were found to be within 5% when compared with the numerical analysis.

scholarly journals Stable solution zone for fluid flow through curved pipe with circular cross-section

2011 ◽  
Vol 7 (1) ◽  
pp. 19-26 ◽  
Author(s):  
M. A. Masud ◽  
Md. Rabiul Islam ◽  
Md. Rasel Sheikh ◽  
Mahmud Md. Alam
Keyword(s):  
Cross Section ◽  
Numerical Study ◽  
Circular Cross Section ◽  
Stable Solution ◽  
Main Tool ◽  
Collocation Methods ◽  
Dean Number ◽  
Curved Pipe ◽  
Wide Range ◽  
Flow Through

Numerical study is performed to examine numerically the stable solution for the incompressible viscous steady flow through a curved pipe with circular cross-section. Also the combined effects of high Dean Number Dn and curvature δ on the flow are investigated. Spectral method is applied as a main tool for the numerical technique; where, Fourier series, Chebyshev polynomials, Collocation methods, and Iteration method are used as secondary tools. The flow patterns have been shown graphically for large Dean Numbers and a wide range of curvature, 0.01≤δ≤0.9.Two vortex solutions have been found for secondary flow. Axial velocity has been found to increase with the increase of Dean number and decrease with the increase of curvature. For high Dean number and low curvature almost all the fluid particles leave the inner half of the cross-section. The stable solution zone increases with the increase of curvature up to a certain limit, then decrease.DOI: 10.3329/jname.v7i1.3630

Numerical study of precession of circulating particles in tokamaks

2011 ◽  
Vol 77 (4) ◽  
pp. 559-569 ◽  
Author(s):  
O. S. BURDO ◽  
YA. I. KOLESNICHENKO ◽  
S. SIPILÄ ◽  
YU. V. YAKOVENKO
Keyword(s):  
Cross Section ◽  
Numerical Study ◽  
Circular Cross Section ◽  
Interpolation Formula ◽  
Plasma Pressure ◽  
Precession Frequency ◽  
Magnetic Shear ◽  
Elliptical Cross ◽  
Reasonable Approximation ◽  
Analytical Expressions

AbstractThe toroidal precession of circulating particles in tokamaks is studied numerically. The dependence of the precession frequency on the magnetic shear, the elongation of the plasma cross-section, and plasma pressure is investigated. It is concluded that the analytical expressions for the precession frequency by Kolesnichenko et al. (2003 Phys. Plasmas10, 1449–1457) represent a reasonable approximation for the limit cases of tokamaks with circular cross-section and shearless tokamaks with elliptical cross-section. The precession frequency was calculated for non-circular tokamaks with magnetic shear. Based on the numerical results, an interpolation formula for the precession frequency is proposed.

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