An Experimental Evaluation of Drag Coefficient for Rectangular Cylinders Exposed to Grid Turbulence

1982 ◽  
Vol 104 (4) ◽  
pp. 523-527 ◽  
Author(s):  
J. Courchesne ◽  
A. Laneville
Keyword(s):  
Drag Coefficient ◽  
Experimental Evaluation ◽  
Grid Turbulence ◽  
Two Dimensional ◽  
Secondary Role ◽  
The Mean ◽  
Rectangular Cylinders

This paper describes an experimental evaluation of the effects of the intensity and scale of turbulence on the drag coefficient of two-dimensional rectangular cylinders exposed to grid turbulence. It is observed that the mean drag coefficient is principally influenced, for a given cylinder, by the intensity of turbulence and that the scale of turbulence plays a secondary role.

A Comparison of Correction Methods Used in the Evaluation of Drag Coefficient Measurements for Two-Dimensional Rectangular Cylinders

1979 ◽  
Vol 101 (4) ◽  
pp. 506-510 ◽  
Author(s):  
J. Courchesne ◽  
A. Laneville
Keyword(s):  
Drag Coefficient ◽  
Experimental Evaluation ◽  
Uniform Flow ◽  
Two Dimensional ◽  
Rectangular Cylinders

This paper describes an experimental evaluation of available drag correction formulae and theories for blockage effects applicable to two-dimensional rectangular cylinders immersed in a low-turbulence uniform flow. It is observed that empirical formulae are functions of the afterbody length and that Maskell’s theory has the tendency to overestimate the correction.

Pressure Distributions and Forces on Rectangular and D-shaped Cylinders

1972 ◽  
Vol 23 (1) ◽  
pp. 1-6 ◽  
Author(s):  
B R Bostock ◽  
W A Mair
Keyword(s):  
Boundary Layer ◽  
Circular Cylinder ◽  
Drag Coefficient ◽  
Pressure Distribution ◽  
Two Dimensional ◽  
Dimensional Flow ◽  
Pressure Distributions ◽  
Two Dimensional Flow ◽  
Rectangular Cylinders ◽  
Shaped Section

SummaryMeasurements in two-dimensional flow on rectangular cylinders confirm earlier work of Nakaguchi et al in showing a maximum drag coefficient when the height h of the section (normal to the stream) is about 1.5 times the width d. Reattachment on the sides of the cylinder occurs only for h/d < 0.35.For cylinders of D-shaped section (Fig 1) the pressure distribution on the curved surface and the drag are considerably affected by the state of the boundary layer at separation, as for a circular cylinder. The lift is positive when the separation is turbulent and negative when it is laminar. It is found that simple empirical expressions for base pressure or drag, based on known values for the constituent half-bodies, are in general not satisfactory.

A one-dimensional self-gravitating stellar gas

1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar
Keyword(s):  
Gravitational Field ◽  
Phase Space ◽  
Motion Picture ◽  
Space Distribution ◽  
Two Dimensional ◽  
One Dimensional ◽  
Phase Space Distribution ◽  
Dimensional Phase Space ◽  
The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

The Influence of Blade Wakes on the Performance of Interturbine Diffusers

1996 ◽  
Vol 118 (2) ◽  
pp. 347-352 ◽  
Author(s):  
R. G. Dominy ◽  
D. A. Kirkham
Keyword(s):  
Performance Modeling ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Two Dimensional ◽  
Correct Performance ◽  
Analysis Methods ◽  
Flow Factor ◽  
The Mean ◽  
Lp Turbine

Interturbine diffusers provide continuity between HP and LP turbines while diffusing the flow upstream of the LP turbine. Increasing the mean turbine diameter offers the potential advantage of reducing the flow factor in the following stages, leading to increased efficiency. The flows associated with these interturbine diffusers differ from those in simple annular diffusers both as a consequence of their high-curvature S-shaped geometry and of the presence of wakes created by the upstream turbine. It is shown that even the simplest two-dimensional wakes result in significantly modified flows through such ducts. These introduce strong secondary flows demonstrating that fully three-dimensional, viscous analysis methods are essential for correct performance modeling.

Effect of thickness-to-chord ratio on the wake of two-dimensional rectangular cylinders

2017 ◽  
Vol 2 (6) ◽  
Author(s):  
Meraj Mohebi ◽  
Phillip du Plessix ◽  
Robert J. Martinuzzi ◽  
David H. Wood
Keyword(s):  
Two Dimensional ◽  
Rectangular Cylinders

scholarly journals Crystal structure of 2-nitro-N-(5-nitro-1,3-thiazol-2-yl)benzamide

2014 ◽  
Vol 70 (12) ◽  
pp. o1252-o1252 ◽  
Author(s):  
Rodolfo Moreno-Fuquen ◽  
Diego F. Sánchez ◽  
Javier Ellena
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Dihedral Angles ◽  
Two Dimensional ◽  
Compound C ◽  
Dimensional Network ◽  
Benzene Rings ◽  
The Mean ◽  
Amide Fragment

In the title compound, C10H6N4O5S, the mean plane of the non-H atoms of the central amide fragment C—N—C(=O)—C [r.m.s. deviation = 0.0294 Å] forms dihedral angles of 12.48 (7) and 46.66 (9)° with the planes of the thiazole and benzene rings, respectively. In the crystal, molecules are linked by N—H...O hydrogen bonds, forming chains along [001]. In addition, weak C—H...O hydrogen bonds link these chains, forming a two-dimensional network, containingR44(28) ring motifs parallel to (100).

Relationship between temporal and spatial averages in grid turbulence

2013 ◽  
Vol 730 ◽  
pp. 593-606 ◽  
Author(s):  
L. Djenidi ◽  
S. F. Tardu ◽  
R. A. Antonia
Keyword(s):  
Strong Support ◽  
Statistical Properties ◽  
Grid Turbulence ◽  
Mean Flow ◽  
Lateral Direction ◽  
Ergodic Hypothesis ◽  
Long Time ◽  
The Mean ◽  
Temporal And Spatial ◽  
Boltzmann Method

AbstractA long-time direct numerical simulation (DNS) based on the lattice Boltzmann method is carried out for grid turbulence with the view to compare spatially averaged statistical properties in planes perpendicular to the mean flow with their temporal counterparts. The results show that the two averages become equal a short distance downstream of the grid. This equality indicates that the flow has become homogeneous in a plane perpendicular to the mean flow. This is an important result, since it confirms that hot-wire measurements are appropriate for testing theoretical results based on spatially averaged statistics. It is equally important in the context of DNS of grid turbulence, since it justifies the use of spatial averaging along a lateral direction and over several realizations for determining various statistical properties. Finally, the very good agreement between temporal and spatial averages validates the comparison between temporal (experiments) and spatial (DNS) statistical properties. The results are also interesting because, since the flow is stationary in time and spatially homogeneous along lateral directions, the equality between the two types of averaging provides strong support for the ergodic hypothesis in grid turbulence in planes perpendicular to the mean flow.

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