A Horseshoe Vortex in a Duct

1984 ◽  
Vol 106 (3) ◽  
pp. 668-676 ◽  
Author(s):  
J. Moore ◽  
T. J. Forlini
Keyword(s):  
Vortex Flow ◽  
Three Dimensional ◽  
Leading Edge ◽  
Horseshoe Vortex ◽  
The Body ◽  
Test Case ◽  
Three Dimensional Flow ◽  
Flow Measurements ◽  
Dimensional Flow ◽  
Side Walls

A Rankine half-body is used to model the three-dimensional flow caused by a blunt obstruction in a flow passage. The body is located in a duct bounded by two plane endwalls and two side walls shaped like potential-flow streamlines. A thick turbulent boundary layer on the endwall forms a horseshoe vortex flow as it encounters the leading edge of the body. Flow measurements are presented showing the inlet flow and the three-dimensional flow downstream of the leading edge. Sufficient data are presented for this to be a test case for the development of three-dimensional viscous flow codes.

A Comparison of Secondary Flow in a Vane Cascade and a Curved Duct

1989 ◽  
Vol 111 (4) ◽  
pp. 530-536 ◽  
Author(s):  
M. T. Boyle ◽  
M. Simonds ◽  
K. Poon
Keyword(s):  
Secondary Flow ◽  
Three Dimensional ◽  
Leading Edge ◽  
Horseshoe Vortex ◽  
Aerodynamic Characteristics ◽  
Duct Flow ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Cascade Flow ◽  
Flow Through

This paper describes an experiment performed to measure the aerodynamic characteristics of the three-dimensional flow through a linear cascade of turbine vanes. The three-dimensional cascade flow is compared to the three-dimensional flow through a duct with a shape similar to the cascade passage shape. The measurements provide a description of the cascade flow and of the duct flow. By comparing the viscous flows for these two geometries, the usefulness of the duct shape for simulating cascade aerodynamics is evaluated. Except in the leading edge region, the qualities of the two flows are very similar. However the secondary flow is stronger in the duct passage than in the vane cascade passage. The effect on the cascade passage flow of the horseshoe vortex generated around the leading edge of each vane is shown to be limited to the region near the leading edge/endwall junction.

Three-dimensional flow measurements in a static mixer

AIChE Journal ◽  
2012 ◽  
Vol 59 (5) ◽  
pp. 1746-1761 ◽  
Author(s):  
R. T. M. Jilisen ◽  
P. R. Bloemen ◽  
M. F. M. Speetjens
Keyword(s):  
Three Dimensional ◽  
Static Mixer ◽  
Three Dimensional Flow ◽  
Flow Measurements ◽  
Dimensional Flow

scholarly journals Calculation of Horseshoe Vortex Flow Without Numerical Mixing

1984 ◽  
Author(s):  
Joan G. Moore ◽  
John Moore
Keyword(s):  
Three Dimensional ◽  
Leading Edge ◽  
Horseshoe Vortex ◽  
Companion Paper ◽  
New Method ◽  
Uniform Grid ◽  
Grid Spacing ◽  
Three Dimensional Flow ◽  
Numerical Mixing ◽  
Well Posed

The usefulness of three-dimensional flow calculations has frequently been obscured by the numerical mixing present in the calculation methods. This paper describes a new method of forming the finite difference momentum equations. The new method results in well posed equations which introduce no numerical mixing. It may be used with orthogonal or non-orthogonal grids and with uniform or highly non-uniform grid spacing. The method is demonstrated by comparing it with upwind differencing on the calculation of a simple example. It is then used in an elliptic pressure-correction calculation procedure to calculate a leading edge horseshoe vortex about a Rankine half body. The results compare well with the experimental data presented in a companion paper.

Experimental Study on the Three-Dimensional Flow Within a Compressor Cascade With Tip Clearance: Part I—Velocity and Pressure Fields

1993 ◽  
Vol 115 (3) ◽  
pp. 435-443 ◽  
Author(s):  
S. Kang ◽  
C. Hirsch
Keyword(s):  
Three Dimensional ◽  
Leading Edge ◽  
Surface Flow ◽  
Tip Clearance ◽  
Tip Vortex ◽  
Compressor Cascade ◽  
Three Dimensional Flow ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Dimensional Flow

Experimental results from a study of the three-dimensional flow in a linear compressor cascade with stationary endwall at design conditions are presented for tip clearance levels of 1.0, 2.0, and 3.3 percent of chord, compared with the no-clearance case. In addition to five-hole probe measurements, extensive surface flow visualizations are conducted. It is observed that for the smaller clearance cases a weak horseshoe vortex forms in the front of the blade leading edge. At all the tip gap cases, a multiple tip vortex structure with three discrete vortices around the midchord is found. The tip leakage vortex core is well defined after the midchord but does not cover a significant area in traverse planes. The presence of the tip leakage vortex results in the passage vortex moving close to the endwall and the suction side.

Transient Growth of Three-Dimensional Vortex Perturbations During Near-Parallel Collision With a Circular Cylinder

2006 ◽  
Author(s):  
X. Liu ◽  
J. S. Marshall
Keyword(s):  
Circular Cylinder ◽  
Vortex Core ◽  
Computational Study ◽  
Three Dimensional ◽  
The Body ◽  
Transient Growth ◽  
Two Dimensional ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Flow Features

A computational study is reported that examines the transient growth of three-dimensional flow features for nominally parallel vortex-cylinder interaction problems. We consider a helical vortex with small-amplitude perturbations that is advected onto a circular cylinder whose axis is parallel to the nominal vortex axis. The study assesses the applicability of the two-dimensional flow assumption for parallel vortex-body interaction problems in which the body impinges on the vortex core. The computations are performed using an unstructured finite-volume method for an incompressible flow, with periodic boundary conditions along the cylinder axis. Growth of three-dimensional flow features is quantified by use of a proper-orthogonal decomposition of the Fourier-transformed velocity and vorticity fields in the cylinder azimuthal and axial directions. The interaction is examined for different axial wavelengths and amplitudes of the initial helical waves on the vortex core, and the results for cylinder force are compared to the two-dimensional results. The degree of perturbation amplification as the vortex approaches the cylinder is quantified and shown to be mostly dependent on the dominant axial wavenumber of the perturbation. The perturbation amplification is observed to be greatest for perturbations with axial wavelength of about 1.5 times the cylinder diameter.

scholarly journals Three-dimensional flow and lift characteristics of a hovering ruby-throated hummingbird

2014 ◽  
Vol 11 (98) ◽  
pp. 20140541 ◽  
Author(s):  
Jialei Song ◽  
Haoxiang Luo ◽  
Tyson L. Hedrick
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Leading Edge ◽  
Dynamics Simulation ◽  
Vertical Force ◽  
Imaging Data ◽  
High Speed Imaging ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Wake Interaction

A three-dimensional computational fluid dynamics simulation is performed for a ruby-throated hummingbird ( Archilochus colubris ) in hovering flight. Realistic wing kinematics are adopted in the numerical model by reconstructing the wing motion from high-speed imaging data of the bird. Lift history and the three-dimensional flow pattern around the wing in full stroke cycles are captured in the simulation. Significant asymmetry is observed for lift production within a stroke cycle. In particular, the downstroke generates about 2.5 times as much vertical force as the upstroke, a result that confirms the estimate based on the measurement of the circulation in a previous experimental study. Associated with lift production is the similar power imbalance between the two half strokes. Further analysis shows that in addition to the angle of attack, wing velocity and surface area, drag-based force and wing–wake interaction also contribute significantly to the lift asymmetry. Though the wing–wake interaction could be beneficial for lift enhancement, the isolated stroke simulation shows that this benefit is buried by other opposing effects, e.g. presence of downwash. The leading-edge vortex is stable during the downstroke but may shed during the upstroke. Finally, the full-body simulation result shows that the effects of wing–wing interaction and wing–body interaction are small.

Numerical Study of Some Three-Dimensional Laminar Free Convective Flows

1976 ◽  
Vol 98 (4) ◽  
pp. 570-575 ◽  
Author(s):  
P. H. Oosthuizen
Keyword(s):  
Numerical Study ◽  
Finite Difference Methods ◽  
Three Dimensional ◽  
The Body ◽  
Three Dimensional Flow ◽  
Constant Property ◽  
Convective Flows ◽  
Boundary Layer Equations ◽  
Dimensional Flow ◽  
Acceleration Component

Three-dimensional buoyancy-induced flows over plates and cylinders have been considered. The three-dimensional flow results either from the fact that the body is inclined to the horizontal or from the fact that there is a longitudinal acceleration component. Both the cases where this acceleration component is constant and the case where it varies linearly with the distance along the body have been considered. The study is based on the use of the constant-property boundary-layer equations. These equations have been rewritten in terms of dimensionless variables, and thus the resulting equations do not explicitly depend on the nature of mechanism causing the three-dimensional flow. These equations have been solved numerically using finite-difference methods, with heat-transfer distributions for various representative situations being deduced.

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