Topic
Drag coefficient
About: Drag coefficient is a research topic. Over the lifetime, 14471 publications have been published within this topic receiving 303196 citations. The topic is also known as: drag factor.
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TL;DR: In this article, the authors considered the interaction between two spherical bubbles for moderate Reynolds numbers (50 ≤ Re ≤ 500, Re being based on the bubble diameter) and for positions described by the separation S======(2.5 ≤ S ≤ 10, S being the distance between the bubble centres normalized by the bubble radius).
Abstract: The three-dimensional flow around two spherical bubbles moving in a viscous fluid is
studied numerically by solving the full Navier-Stokes equations. The study considers the
interaction between two bubbles for moderate Reynolds numbers (50 ≤ Re ≤ 500, Re
being based on the bubble diameter) and for positions described by the separation S
(2.5 ≤ S ≤ 10, S being the distance between the bubble centres normalized by the
bubble radius) and the angle θ (0o ≤ θ ≤ 90o ) formed between the line of centre and the
direction perpendicular to the direction of the motion. We provide a general description
of the interaction extending the results obtained for two bubbles moving side by side
(θ = 0o ) by Legendre, Magnaudet & Mougin 2003 (J. Fluid Mech., 497,133-166) and
for two bubbles moving in line (θ = 90o ) by Yuan & Prosperetti 1994 (J. Fluid Mech.,
278, 325-349). Simple models based on physical arguments are given for the drag and lift
forces experienced by each bubble. The interaction is the combination of three effects:
a potential effect, a viscous correction (Moore correction) and a significant wake effect
observed on both the drag and the transverse force of the second bubble when located
in the wake of the first one.
82 citations
TL;DR: In this paper, pressure drop measurements were made on a variety of dilute solid-liquid suspension systems in order to study the effects of particle shape and size, concentration, fluid viscosity, and tube diameter on friction factor.
Abstract: Pressure drop measurements were made on a variety of dilute solid-liquid suspension systems in order to study the effects of particle shape and size, concentration, fluid viscosity, and tube diameter on friction factor. The central objective was to determine under what conditions drag reduction would occur.
82 citations
TL;DR: In this article, an unusual stress controlled turbulent flow phenomenon observed in aqueous solutions of some derivatives of an unsaturated 18 carbon atom fatty acid is described, and some other unusual viscometric and rheogoniometric properties of these solutions are also discussed.
Abstract: An unusual stress controlled turbulent flow phenomenon observed in aqueous solutions of some derivatives of an unsaturated 18 carbon atom fatty acidis described. Some other unusual viscometric and rheogoniometric properties of these solutions are also discussed.
82 citations
TL;DR: In this paper, the authors improved the numerical value of the drag coefficient by inserting the appropriate parameters in theoretical models of the coefficient, which provided increased consistency in orbital measurements of atmospheric density.
Abstract: Signi cant discoveries about gas–surface interactions that havebeen made in 90 years of laboratory experiments and 30 years of orbital measurements are reviewed. This information is used to improve the calculation of drag coef cients for satellites in low Earth orbit for several different satellite shapes and orientations by inserting the appropriate parameters in theoretical models of the drag coef cient. The drag coef cients so calculated provide increased consistency in orbital measurements of atmospheric density by satellites of different shapes near 200 km, where adsorbed atomic oxygen dominates the interaction and causes the energy accommodation coef cient to approach unity. It is essential to improve the numerical value of the drag coef cient so that the density of the neutral thermosphere can be inferred from satellite drag to better than the present 15% uncertainty. The key to this improvement is the calculationof drag coef cients from parametersmeasured in space, rather than from those measured in the laboratory under conditions very different from the space environment.
82 citations
TL;DR: In this paper, the ability of a two-fluid Eulerian-Eulerian computational multiphase fluid dynamic model to predict bubbly air-water flows is studied.
82 citations