Unsteady drag coefficient of spherical particles moving on the pipe wall : In the wide range of particle density and pressure wave

2003 ◽  
Vol 2003 (0) ◽  
pp. 167-168
Author(s):  
Syuuichi Kawasaki ◽  
Masaaki Horie ◽  
Hideo Ide ◽  
Hisayoshi Kado
Keyword(s):  
Drag Coefficient ◽  
Pressure Wave ◽  
Pipe Wall ◽  
Particle Density ◽  
Spherical Particles ◽  
Wide Range

Settling Behavior of Particles in Bubble Containing Newtonian Fluids: Experimental Study and Model Development

2021 ◽  
Author(s):  
Silin Jing ◽  
Xianzhi Song ◽  
Zhaopeng Zhu ◽  
Buwen Yu ◽  
Shiming Duan
Keyword(s):  
Reynolds Number ◽  
Drag Coefficient ◽  
Volume Concentration ◽  
Settling Velocity ◽  
Particle Density ◽  
Particle Diameter ◽  
Newtonian Fluids ◽  
Spherical Particles ◽  
Bubble Volume ◽  
Particle Reynolds Number

Abstract Accurate description of cuttings slippage in the gas-liquid phase is of great significance for wellbore cleaning and the control accuracy of bottom hole pressure during MPD. In this study, the wellbore bubble flow environment was simulated by a constant pressure air pump and the transparent wellbore, and the settling characteristics of spherical particles under different gas volume concentrations were recorded and analyzed by highspeed photography. A total of 225 tests were conducted to analyze the influence of particle diameter (1–12mm), particle density (2700–7860kg/m^3), liquid viscosity and bubble volume concentration on particle settling velocity. Gas drag force is defined to quantitatively evaluate the bubble’s resistance to particle slippage. The relationship between bubble drag coefficient and particle Reynolds number is obtained by fitting the experimental results. An explicit settling velocity equation is established by introducing Archimedes number. This explicit equation with an average relative error of only 8.09% can directly predict the terminal settling velocity of the sphere in bubble containing Newtonian fluids. The models for predicting bubble drag coefficient and the terminal settling velocity are valid with particle Reynolds number ranging from 0.05 to 167 and bubble volume concentration ranging from 3.0% to 20.0%. Besides, a trial-and-error procedure and an illustrative example are presented to show how to calculate bubble drag coefficient and settling velocity in bubble containing fluids. The results of this study will provide the theoretical basis for wellbore cleaning and accurate downhole pressure to further improve the performance of MPD in treating gas influx.

Explicit relationships for the terminal velocity of spherical particles

1990 ◽  
Vol 55 (2) ◽  
pp. 403-408 ◽  
Author(s):  
Miloslav Hartman ◽  
Václav Veselý ◽  
Karel Svoboda ◽  
Vladimír Havlín
Keyword(s):  
Drag Coefficient ◽  
Free Fall ◽  
Terminal Velocity ◽  
Spherical Particles ◽  
Wide Range ◽  
Archimedes Number

The Turton-Levenspiel correlation for the drag coefficient of a sphere is employed to compare recently proposed explicit equations to predict the free-fall conditions. Predictions of four different expressions are explored over a wide range of Archimedes number.

Drag coefficient of a sphere in a non-stationary flow: new results

2007 ◽  
Vol 463 (2088) ◽  
pp. 3323-3345 ◽  
Author(s):  
G Jourdan ◽  
L Houas ◽  
O Igra ◽  
J.-L Estivalezes ◽  
C Devals ◽  
...  
Keyword(s):  
Drag Coefficient ◽  
Stationary Flow ◽  
Reynolds Numbers ◽  
Spherical Particles ◽  
Steady Flows ◽  
Two Phase ◽  
Spider Web ◽  
Wide Range ◽  
The Difference ◽  
Sphere Drag

The drag coefficient of a sphere placed in a non-stationary flow is studied experimentally over a wide range of Reynolds numbers in subsonic and supersonic flows. Experiments were conducted in a shock tube where the investigated balls were suspended, far from all the tube walls, on a very thin wire taken from a spider web. During each experiment, many shadowgraph photos were taken to enable an accurate construction of the sphere's trajectory. Based on the sphere's trajectory, its drag coefficient was evaluated. It was shown that a large difference exists between the sphere drag coefficient in steady and non-steady flows. In the investigated range of Reynolds numbers, the difference exceeds 50%. Based on the obtained results, a correlation for the non-stationary drag coefficient of a sphere is given. This correlation can be used safely in simulating two-phase flows composed of small spherical particles immersed in a gaseous medium.

Numerical investigation of anguilliform locomotion by the SPH method

2019 ◽  
Vol 30 (1) ◽  
pp. 328-346 ◽  
Author(s):  
Amin Rahmat ◽  
Hossein Nasiri ◽  
Marjan Goodarzi ◽  
Ehsan Heidaryan
Keyword(s):  
Drag Coefficient ◽  
Numerical Investigation ◽  
Sph Method ◽  
Content Type ◽  
Aquatic Locomotion ◽  
Wide Range ◽  
Particle Hydrodynamics ◽  
Dummy Particles ◽  
Smoothed Particle ◽  
Sph Algorithm

Purpose This paper aims to introduce a numerical investigation of aquatic locomotion using the smoothed particle hydrodynamics (SPH) method. Design/methodology/approach To model this problem, a simple improved SPH algorithm is presented that can handle complex geometries using updatable dummy particles. The computational code is validated by solving the flow over a two-dimensional cylinder and comparing its drag coefficient for two different Reynolds numbers with those in the literature. Findings Additionally, the drag coefficient and vortices created behind the aquatic swimmer are quantitatively and qualitatively compared with available credential data. Afterward, the flow over an aquatic swimmer is simulated for a wide range of Reynolds and Strouhal numbers, as well as for the amplitude envelope. Moreover, comprehensive discussions on drag coefficient and vorticity patterns behind the aquatic are made. Originality/value It is found that by increasing both Reynolds and Strouhal numbers separately, the anguilliform motion approaches the self-propulsion condition; however, the vortices show different pattern with these increments.

Calculation of the primary trajectories of seeds and other particles in strong winds

1983 ◽  
Vol 219 (1215) ◽  
pp. 217-217
Keyword(s):  
Equations Of Motion ◽  
Aerodynamic Resistance ◽  
Reynolds Numbers ◽  
Spherical Particles ◽  
Spores And Pollen ◽  
General Terms ◽  
Wide Range ◽  
Strong Winds ◽  
Dispersal Distances ◽  
Enormous Number

The movement of variously dense spherical particles representing a variety of seeds, fruits, spores and pollen, and released from rest into arbitrary winds and a gravitational field is discussed in general terms that account in detail for changes in the quasi-static aerodynamic resistance to motion experienced by such particles during aerial flight. A hybrid analytical-empirical law is established which describes this resistance fairly accurately for particle Reynolds numbers in the range 0—60 000 and that allows for the numerical integration of the equations of motion so as to cover a very wide range of flight conditions. This makes possible the provision of a set of four-parameter universal range tables from which the dispersal distances for an enormous number of practical cases may be estimated. One particular case of particle movement in a region of pseudo-thermal convection is also discussed and this shows how a marked degree of deposition concentration may be induced in some circumstances by such a flow. Botanists and ecologists concerned with seed and particle dispersal in the environment may find the universal range tables of particular interest and use. This is because the tables obviate the need for the integration of the equations of motion when dealing with individual cases and permit an estimation of range purely on the basis of the specified quantities of particle size, density and altitude of release, atmospheric wind speed, density and viscosity, and the acceleration due to gravity.

Drag Coefficient and Two-Phase Friction Multiplier on Tube Bundles Subjected to Two-Phase Cross-Flow

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
W. G. Sim ◽  
Njuki W. Mureithi
Keyword(s):  
Drag Coefficient ◽  
Void Fraction ◽  
Euler Number ◽  
Tube Bundle ◽  
Cross Flow ◽  
Water Mixture ◽  
Duct Flow ◽  
Two Phase ◽  
Mass Fluxes ◽  
Wide Range

An approximate analytical model, to predict the drag coefficient on a cylinder and the two-phase Euler number for upward two-phase cross-flow through horizontal bundles, has been developed. To verify the model, two sets of experiments were performed with an air–water mixture for a range of pitch mass fluxes and void fractions. The experiments were undertaken using a rotated triangular (RT) array of cylinders having a pitch-to-diameter ratio of 1.5 and cylinder diameter 38 mm. The void fraction model proposed by Feenstra et al. was used to estimate the void fraction of the flow within the tube bundle. An important variable for drag coefficient estimation is the two-phase friction multiplier. A new drag coefficient model has been developed, based on the single-phase flow Euler number formulation proposed by Zukauskas et al. and the two-phase friction multiplier in duct flow formulated by various researchers. The present model is developed considering the Euler number formulation by Zukauskas et al. as well as existing two-phase friction multiplier models. It is found that Marchaterre's model for two-phase friction multiplier is applicable to air–water mixtures. The analytical results agree reasonably well with experimental drag coefficients and Euler numbers in air–water mixtures for a sufficiently wide range of pitch mass fluxes and qualities. This model will allow researchers to provide analytical estimates of the drag coefficient, which is related to two-phase damping.

scholarly journals IN VITRO CYTOTOXICITY AND ANTIOXIDANT EVALUATION OF BIOGENIC SYNTHESIZED GOLD NANOPARTICLES FROM MARSILEA QUADRIFOLIA ON LUNG AND OVARIAN CANCER CELLS

2018 ◽  
Vol 10 (5) ◽  
pp. 153 ◽  
Author(s):  
Balashanmugam P. ◽  
Mosa Christas K. ◽  
Kowsalya E.
Keyword(s):  
Gold Nanoparticles ◽  
Cell Lines ◽  
Aqueous Extract ◽  
A549 Cell ◽  
In Vitro Cytotoxicity ◽  
Spherical Particles ◽  
X Ray ◽  
Marsilea Quadrifolia ◽  
Wide Range

Objective: The biogenic gold nanoparticles are considered to be extremely impressive for its wide range of applications in pharmaceutics and therapeutics. The present study was aimed at the biogenic synthesis of gold nanoparticles (AuNPs) from Marsilea quadrifolia aqueous extract and to investigate its antioxidant property and cytotoxic effect on human ovarian teratocarcinoma (PA-1) and lung adenocarcinoma (A549) cell lines.Methods: The biogenic AuNPs was synthesized using an aqueous extract of Marsilea quadrifolia. The synthesized biogenic AuNPs were characterized by ultraviolet (UV) visible spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD). The biogenic AuNPs was assessed for its stability over a period of time and antioxidant activity. The cytotoxicity of biogenic AuNPs against PA-1 and A549 cell lines was studied using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.Results: The synthesized biogenic AuNPs showed peculiar ruby red color and a surface plasmon resonance (SPR) peak at 544 nm in the UV-Vis spectrum. The characterization of biogenic AuNPs by TEM, EDX and XRD revealed well dispersed spherical particles ranging from 10-40 nm and the presence of elemental gold and its crystalline nature, respectively. The AuNPs showed good stability and the scavenging activity at 50 μg/ml. The in vitro cytotoxicity of biogenic AuNPs against PA-1 and A549 cell lines recorded half maximal inhibitory concentration (IC50) of 45.88 μg/ml and 52.015 μg/ml, respectively.Conclusion: The biogenic AuNPs demonstrated superior antioxidant and antiproliferative activities against cancer cell lines.

Comment on "Drag Coefficient of Small Spherical Particles"

AIAA Journal ◽  
1969 ◽  
Vol 7 (3) ◽  
pp. 573-574
Author(s):  
FREDERICK L. SCHUYLER
Keyword(s):  
Drag Coefficient ◽  
Spherical Particles
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