Terminal velocity and drag coefficient models for disc-shaped particles based on the imaging experiment

2021 ◽  
pp. 117062
Author(s):  
Changjiang Zhou ◽  
Jie Su ◽  
Haikang Chen ◽  
Zhaoyao Shi
Keyword(s):  
Drag Coefficient ◽  
Terminal Velocity ◽  
Imaging Experiment

On the Penetrator Nose Drag Measurements

2010 ◽  
Author(s):  
Joseph P. Holland ◽  
Yesenia Tanner ◽  
Phillip A. Schinetsky ◽  
Semih Olcmen ◽  
Stanley Jones
Keyword(s):  
Wind Tunnel ◽  
Power Series ◽  
Viscous Fluid ◽  
Drag Coefficient ◽  
Aerodynamic Drag ◽  
Terminal Velocity ◽  
Force Balance ◽  
Supersonic Wind Tunnel ◽  
Buoyant Force ◽  
Nose Shape

In the current study, a rigid body penetrator nose shape that is optimized for minimum penetration drag [1] has been tested to determine the aerodynamic drag of such a penetrator in comparison to three additional nose shapes. Other nose shapes tested were an ogive cylinder, a 3/4 power series nose, and a standard cone. Fineness ratio for the studied nose geometries was chosen as l/d = 1 to maximize variation of the aerodynamic drag forces acting on the nose shapes. This paper discusses the measurements carried out in the University of Alabama’s 6″ × 6″ supersonic wind tunnel, using a 4 component force balance system. In separate experiments, drop tests were made in a viscous fluid to determine the skin-friction effects on these nose shapes. Supersonic wind-tunnel experiments were performed on each of the nose shapes at nine different Mach numbers ranging from 2 to 3.65. Results show that the nose shape optimized for penetration has the lowest drag coefficient of all the shapes at each Mach number within an uncertainty of 5.75%. In the viscous flow drop-test experiments, each nose shape was dropped from rest through water and then separately through viscous fluid (Nu-Calgon vacuum pump oil) under freefall conditions. Each drop was recorded via videotape, and the video was then analyzed to find the terminal velocity of each individual nose shape. Using classical dynamics equations, the weight, buoyant force, and experimentally determined terminal velocity are used to determine the drag force applied to each nose cone shape. Results indicate that while the optimal shape has a lesser drag coefficient than tangent ogive and the cone, the 3/4 power series shape is observed to have the least drag coefficient. In addition to the experiments performed, results on further investigation of the optimal nose shape for penetration are presented. The nose shape has been split into a series of line segments, and a program written has been utilized to search through numerical space for the combination of line segment slopes that produces the nose geometry with the lowest nose shape factor. The results of the numerical analysis in this study point to a different nose shape than the “optimal nose” shape tested in the current study.

scholarly journals Aerodynamic Properties of Makhobeli, Triticale and Wheat Seeds

2014 ◽  
Vol 28 (3) ◽  
pp. 389-394 ◽  
Author(s):  
Feizollah Shahbazi ◽  
Saman Valizadeh ◽  
Ali Dowlatshah
Keyword(s):  
Moisture Content ◽  
Drag Coefficient ◽  
Terminal Velocity ◽  
Mean Value ◽  
Probability Level ◽  
Mean Values ◽  
Aerodynamic Properties ◽  
The Mean ◽  
Content Range ◽  
Wheat Seeds

Abstract The objective of this study was the evaluation of the aerodynamic properties of Makhobeli, triticale and wheat seeds as a function of moisture content from 7 to 27% (w.b). The results showed that the terminal velocity of triticale and wheat seeds increased linearly from 5.37 to 6.42 and from 6.31 to 8.02 m s-1, respectively, as the moisture content increased from 7 to 27%. Over this same moisture content range, the terminal velocity of Makhobeli seeds varied following a polynomial relationship from 4.52 to 5.07 m s-1. Makhobeli seeds had terminal velocities with a mean value of 4.73 m s-1, at different moisture contents, compared to the mean values of 5.89 and 7.13 m s-1 for triticale and wheat seeds, respectively. The mean value of drag coefficient was 1.12 for Makhobeli compared to the values of 0.92 and 0.85 for triticale and wheat, respectively. The analysis of variance showed that there were significant differences between the terminal velocity (at 1 % probability level) and drag coefficient (at 5% probability level) of Mak-hobeli with triticale and wheat seeds, which suggests that aerodynamic separation of Makhobeli from triticale and wheat is possible.

An Experimental Investigation for Bubble Rising in Non-Newtonian Fluids and Empirical Correlation of Drag Coefficient

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Fan Wenyuan ◽  
Ma Youguang ◽  
Jiang Shaokun ◽  
Yang Ke ◽  
Li Huaizhi
Keyword(s):  
Reynolds Number ◽  
Aqueous Solutions ◽  
Drag Coefficient ◽  
Bubble Diameter ◽  
Video Camera ◽  
Solution Concentration ◽  
Terminal Velocity ◽  
Newtonian Fluids ◽  
Rising Bubble ◽  
Moderate Reynolds Number

The velocity, shape, and trajectory of the rising bubble in polyacrylamide (PAM) and carboxymethylcellulose (CMC) aqueous solutions were experimentally investigated using a set of homemade velocimeters and a video camera. The effects of gas the flowrate and solution concentration on the bubble terminal velocity were examined respectively. Results show that the terminal velocity of the bubble increases with the increase in the gas flowrate and the decrease in the solution concentration. The shape of the bubble is gradually flattened horizontally to an ellipsoid with the increase in the Reynolds number (Re), Eötvös number (Eo), and Morton number (Mo). With the increase in the Re and Eo, the rising bubble in PAM aqueous solutions begin to oscillate, but there is no oscillation phenomena for CMC aqueous solutions. By dimensional analysis, the drag coefficient of a single bubble in non-Newtonian fluids in a moderate Reynolds number was correlated as a function of Re, Eo, and Archimedes number (Ar) based on the equivalent bubble diameter. The predicted results by the present correlation agree well with the experimental data.

scholarly journals Terminal Velocity and Drag Coefficient of Single Air Bubbles in Stagnant Water Filling in Narrow Parallel Walls.

1996 ◽  
Vol 10 (2) ◽  
pp. 146-153 ◽  
Author(s):  
Akio TOMIYAMA ◽  
Shigeo HOSOKAWA ◽  
Masahiko EBARA ◽  
Yoshiharu MIYANAGA ◽  
Yoshio KAWAKUBO ◽  
...  
Keyword(s):  
Drag Coefficient ◽  
Terminal Velocity ◽  
Air Bubbles ◽  
Stagnant Water ◽  
Water Filling

scholarly journals Determination of Physical Properties, Moisture Absorption Process and Aerodynamic Properties of Grain and Cluster Straw of Two Wheat Cultivars

2020 ◽  
Vol 68 (5) ◽  
pp. 831-840
Author(s):  
Mohammad Jafari ◽  
Gholam Reza Chegini ◽  
Javad Khazaei
Keyword(s):  
Physical Properties ◽  
Drag Coefficient ◽  
Moisture Absorption ◽  
Mass Density ◽  
Terminal Velocity ◽  
Wheat Cultivars ◽  
Projected Area ◽  
Drag Forces ◽  
Aerodynamic Properties

In this study, physical properties of grain and cluster straw including geometric dimensions, moisture absorption and aerodynamic properties of two wheat cultivars were investigated. The effect of cultivar on width, thickness, geometric diameter, spheroid coefficient and mass density was significant at 1% probability level whilst there were no significant effect on grain projected area, length and weight. Moisture absorption of the grains was rapid during the first 30–40 min and then turned to zero. The terminal velocity of wheat grain and straw in three shapes was measured by calculating the projected area in horizontal, lateral and perpendicular directions and then, the drag coefficient was obtained by the equilibrium of the gravity and drag forces at the terminal velocity. Results also showed that increasing moisture content resulted in an increase in the terminal velocity and a decrease in the drag coefficient. Results obtained in this study can be used in designing wheat- cluster straw separation and processing.

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.

Aerodynamic properties of Faba bean (Vicia faba L.) Seeds

2016 ◽  
Vol 39 (3) ◽  
Author(s):  
Mesut Dilmac ◽  
Sefa Tarhan ◽  
Hakan Polatci
Keyword(s):  
Moisture Content ◽  
Physical Properties ◽  
Drag Coefficient ◽  
Vicia Faba ◽  
Faba Bean ◽  
Terminal Velocity ◽  
Moisture Contents ◽  
Aerodynamic Properties ◽  
Agricultural Materials ◽  
Agricultural Material

Aerodynamic properties of agricultural materials are the physical properties considering the reaction of agricultural material piles or seeds against airflow. The airflow resistance of faba bean (<italic>Vicia faba</italic> L.) seed piles was experimentally determined and mathematically modeled for two different moisture contents (11.4 % and 25.8% w.b.) for the superficial air velocities ranging from 0.0225 to 1.395 m<sup>3</sup>·m<sup>−2</sup>·s<sup>−1</sup>. Modified Shedd’s equation and Hukill-Ives equation can be interchangeably used to design aeration systems for the storage and drying bins of faba bean seeds. The terminal velocity values are 11.68 and 12.87 m·s<sup>−1</sup> for the moisture contents of 11.4% and 25.8% (w.b.), respectively. The drag coefficient values are 1.02 and 0.88 for the moisture contents of 11.4% and 25.8% (w.b.), respectively. Moisture content increased terminal velocity but decreased drag coefficient.

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