scholarly journals VELOCITY CHARACTERISTICS IN WAKE OF A NON-SPHERE BODY AND IN PORE OF POROUS MEDIA COMPOSED OF NON-SPHERES

2020 ◽  
pp. 58
Author(s):  
Yuji Yamamura ◽  
Takaaki Shigematsu ◽  
Sota Nakajo
Keyword(s):  
Porous Media ◽  
Velocity Field ◽  
Steady Flow ◽  
Turbulence Intensity ◽  
Angle Of Attack ◽  
Prolate Spheroid ◽  
Weak Turbulence ◽  
Velocity Change ◽  
Hydraulic Experiment ◽  
Significant Change

Details of a velocity field around a prolate spheroid in a steady flow with different angles of attack were investigated by carrying out a hydraulic experiment using the PTV technique. It was found that characteristics of the vortex in the wake of the prolate spheroid were different depending on the angle of attack. It was clearly found that the velocity field changes significantly in the wake. That is to say that there were some areas with strong and weak turbulence and that also some areas with a certain periodic and unclear periodic velocity change with significant change. It was clear that these characteristics depend on the angle of attack of the spheroid. Further, it was confirmed that the distribution of the turbulence intensity was different between the horizontal and vertical components.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/34Dw1CSLEz4

Steady flow through porous media

AIChE Journal ◽  
1981 ◽  
Vol 27 (4) ◽  
pp. 529-545 ◽  
Author(s):  
R. A. Greenkorn
Keyword(s):  
Porous Media ◽  
Steady Flow ◽  
Flow Through Porous Media ◽  
Flow Through

Steady Flow in the Transition Length of a Straight Tube

1942 ◽  
Vol 9 (2) ◽  
pp. A55-A58 ◽  
Author(s):  
Henry L. Langhaar
Keyword(s):  
Velocity Field ◽  
Steady Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Straight Tube ◽  
Pressure Function ◽  
Navier Stokes Equations ◽  
Dimensionless Constant ◽  
The Family ◽  
Transition Length

Abstract By means of a linearizing approximation, the Navier-Stokes equations are solved for the case of steady flow in the transition length of a straight tube. The family of velocity profiles is defined by Bessel functions, and the parameter of this family is tabulated against the axial co-ordinate in a dimensionless form. Hence, the length of transition is obtained. The curves give a comparison of the author’s calculations of the velocity field with those of other investigators, and with the experimental data of Nikuradse. The pressure function is derived from the computed velocity field by means of the energy equation, and the pressure drop in the transition length is defined by a dimensionless constant m, which is computed to be 2.28. A discussion of this constant is given in the conclusions.

Homogenization of saturated double porous media with Eshelby-like velocity field

2014 ◽  
Vol 62 (5) ◽  
pp. 1146-1162 ◽  
Author(s):  
Wanqing Shen ◽  
Emma Lanoye ◽  
Luc Dormieux ◽  
Djimedo Kondo
Keyword(s):  
Porous Media ◽  
Velocity Field ◽  
Double Porous Media

Inertial Deposition Effects: A Study of Aerosol Mechanics in the Trachea Using Laser Doppler Velocimetry and Fluorescent Dye

2002 ◽  
Vol 124 (6) ◽  
pp. 629-637 ◽  
Author(s):  
T. E. Corcoran ◽  
Norman Chigier
Keyword(s):  
Steady Flow ◽  
Turbulence Intensity ◽  
Axial Velocity ◽  
Laser Doppler Velocimetry ◽  
Aerosol Deposition ◽  
Fluorescent Dye ◽  
Laser Doppler ◽  
Doppler Velocimetry ◽  
Flow Rates ◽  
Phase Doppler Interferometry

This study characterizes the axial velocity and axial turbulence intensity patterns noted in the tracheal portion of a cadaver-based throat model at two different steady flow rates (18.1 and 41.1 LPM.) This characterization was performed using Phase Doppler Interferometry (Laser Doppler Velocimetry). Deposition, as assessed qualitatively using fluorescent dye, is related to the position of the laryngeal jet within the trachea. The position of the jet is dependent on the downstream conditions of the model. It is proposed therefore that lung/airway conditions may have important effects on aerosol deposition within the throat. There is no correspondence noted between regions of high axial turbulence intensity and deposition.

Numerical Investigation of Flow Past a Prolate Spheroid

2002 ◽  
Vol 124 (4) ◽  
pp. 904-910 ◽  
Author(s):  
George S. Constantinescu ◽  
Hugo Pasinato ◽  
You-Qin Wang ◽  
James R. Forsythe ◽  
Kyle D. Squires
Keyword(s):  
Skin Friction ◽  
Turbulence Model ◽  
Pressure Coefficient ◽  
Angle Of Attack ◽  
Prolate Spheroid ◽  
Leeward Side ◽  
Experimental Measurements ◽  
Axial Pressure ◽  
Streamline Curvature ◽  
Axial Pressure Gradient

The flowfield around a 6:1 prolate spheroid at angle of attack is predicted using solutions of the Reynolds-averaged Navier-Stokes (RANS) equations and detached-eddy simulation (DES). The calculations were performed at a Reynolds number of 4.2×106, the flow is tripped at x/L=0.2, and the angle of attack α is varied from 10 to 20 deg. RANS calculations are performed using the Spalart-Allmaras one-equation model. The influence of corrections to the Spalart-Allmaras model accounting for streamline curvature and a nonlinear constitutive relation are also considered. DES predictions are evaluated against experimental measurements, RANS results, as well as calculations performed without an explicit turbulence model. In general, flowfield predictions of the mean properties from the RANS and DES are similar. Predictions of the axial pressure distribution along the symmetry plane agree well with measured values for 10 deg angle of attack. Changes in the separation characteristics in the aft region alter the axial pressure gradient as the angle of attack increases to 20 deg. With downstream evolution, the wall-flow turning angle becomes more positive, an effect also predicted by the models though the peak-to-peak variation is less than that measured. Azimuthal skin friction variations show the same general trend as the measurements, with a weak minima identifying separation. Corrections for streamline curvature improve prediction of the pressure coefficient in the separated region on the leeward side of the spheroid. While initiated further along the spheroid compared to experimental measurements, predictions of primary and secondary separation agree reasonably well with measured values. Calculations without an explicit turbulence model predict pressure and skin-friction distributions in substantial disagreement with measurements.

The effect of order on dispersion in porous media

1989 ◽  
Vol 200 ◽  
pp. 173-188 ◽  
Author(s):  
Donald L. Koch ◽  
Raymond G. Cox ◽  
Howard Brenner ◽  
John F. Brady
Keyword(s):  
Porous Media ◽  
Velocity Field ◽  
Fluid Velocity ◽  
Fluid Motion ◽  
Grain Structure ◽  
Disordered Media ◽  
Molecular Diffusivity ◽  
Mechanical Dispersion ◽  
Spatial Periodicity ◽  
Flow Through

The effect of spatial periodicity in grain structure on the average transport properties resulting from flow through porous media are derived from the basic conservation equations. At high Péclet number, the mechanical dispersion that is induced by the stochastic fluid velocity field in disordered media and is independent of the molecular diffusivity is absent in periodic media where the velocity field is deterministic. Instead, the fluid motion enhances diffusion by an amount proportional to U2l2/D when the bulk flow is in certain directions (of which there are an infinite number), and to D otherwise. The non-mechanical dispersion mechanisms associated with the zero velocity of the fixed grains is qualitatively similar in ordered and disordered media.

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