Brownian deposition of aerosol particles from turbulent flow through pipes

1966 ◽  
Vol 290 (1423) ◽  
pp. 557-562 ◽  
Keyword(s):  
Brownian Motion ◽  
Turbulent Flow ◽  
Aerosol Particles ◽  
Small Particles ◽  
Fully Developed Turbulent Flow ◽  
Flow Through

A previous paper gave an account of a method of calculating the velocity of deposition of aerosol particles upon the wall of a pipe through which they were passing in fully developed turbulent flow. This is now extended to include small particles which diffuse at an appreciable rate owing to their Brownian motion.

One-Dimensional Fully Developed Turbulent Flow through Coarse Porous Medium

2014 ◽  
Vol 19 (7) ◽  
pp. 1491-1496 ◽  
Author(s):  
Mohammad Sedghi-Asl ◽  
Hassan Rahimi ◽  
Javad Farhoudi ◽  
Abdolhossein Hoorfar ◽  
Sven Hartmann
Keyword(s):  
Porous Medium ◽  
Turbulent Flow ◽  
One Dimensional ◽  
Fully Developed Turbulent Flow ◽  
Flow Through

Turbulent flow in smooth concentric annuli with small radius ratios

1974 ◽  
Vol 64 (2) ◽  
pp. 263-288 ◽  
Author(s):  
K. Rehme
Keyword(s):  
Reynolds Number ◽  
Shear Stress ◽  
Turbulent Flow ◽  
Strong Influence ◽  
Maximum Velocity ◽  
Small Radius ◽  
Stress Distributions ◽  
Number Range ◽  
Fully Developed Turbulent Flow ◽  
Flow Through

Fully developed turbulent flow through three concentric annuli was investigated experimentally for a Reynolds-number rangeRe= 2 × 104−2 × 105. Measurements were made of the pressure drop, the positions of zero shear stress and maximum velocity, and the velocity distribution in annuli of radius ratios α = 0.02, 0.04 and 0.1, respectively. The results for the key problem in the flow through annuli, the position of zero shear stress, showed that this position is not coincident with the position of maximum velocity. Furthermore, the investigation showed the strong influence of spacers on the velocity and shear-stress distributions. The numerous theoretical and experimental results in the literature which are based on the coincidence of the positions of zero shear stress and maximum velocity are not in agreement with reality.

Flow Through a Finite Packed Bed of Spheres: A Note on the Limit of Applicability of the Forchheimer-Type Equation

2004 ◽  
Vol 126 (1) ◽  
pp. 139-143 ◽  
Author(s):  
Agne`s Montillet
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Turbulent Flow ◽  
Flow Regime ◽  
Fluid Velocity ◽  
Type Equation ◽  
Packed Bed ◽  
Turbulent Flow Regime ◽  
Fully Developed Turbulent Flow ◽  
Flow Through

The variation of the pressure drop measured as a function of the fluid velocity through a packed bed of spheres is presented and discussed in the range of particle Reynolds number 30–1500. Based on previous studies, the observed limit of validity of the so-called Forchheimer law may be attributed to the concomitant effects of the finite character of the tested bed and of the transition of flow regime which is marking the beginning of the fully developed turbulent flow regime. The limit of validity of the Forchheimer-type law was formerly noticed by several authors.

scholarly journals Developing and fully developed turbulent flow through annuli.

1980 ◽  
Vol 13 (5) ◽  
pp. 349-353 ◽  
Author(s):  
R. P. SINGH ◽  
K. K. NIGAM ◽  
P. MISHRA
Keyword(s):  
Turbulent Flow ◽  
Fully Developed Turbulent Flow ◽  
Flow Through

Enhanced secondary motion of the turbulent flow through a porous square duct

2015 ◽  
Vol 784 ◽  
pp. 681-693 ◽  
Author(s):  
A. Samanta ◽  
R. Vinuesa ◽  
I. Lashgari ◽  
P. Schlatter ◽  
L. Brandt
Keyword(s):  
Turbulent Flow ◽  
Numerical Simulations ◽  
Boundary Layers ◽  
Stokes Equations ◽  
Porous Wall ◽  
Packed Bed ◽  
Square Duct ◽  
Fully Developed Turbulent Flow ◽  
Porous Interface ◽  
Flow Through

Direct numerical simulations of the fully developed turbulent flow through a porous square duct are performed to study the effect of the permeable wall on the secondary cross-stream flow. The volume-averaged Navier–Stokes equations are used to describe the flow in the porous phase, a packed bed with porosity ${\it\varepsilon}_{c}=0.95$. The porous square duct is computed at $\mathit{Re}_{b}\simeq 5000$ and compared with the numerical simulations of a turbulent duct with four solid walls. The two boundary layers on the top wall and porous interface merge close to the centre of the duct, as opposed to the channel, because the sidewall boundary layers inhibit the growth of the shear layer over the porous interface. The most relevant feature in the porous duct is the enhanced magnitude of the secondary flow, which exceeds that of a regular duct by a factor of four. This is related to the increased vertical velocity, and the different interaction between the ejections from the sidewalls and the porous medium. We also report a significant decrease in the streamwise turbulence intensity over the porous wall of the duct (which is also observed in a porous channel), and the appearance of short spanwise rollers in the buffer layer, replacing the streaky structures of wall-bounded turbulence. These spanwise rollers most probably result from a Kelvin–Helmholtz type of instability, and their width is limited by the presence of the sidewalls.

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