Prediction of tunnel wall upwash for delta wings including vortex breakdown effects

1999 ◽  
Vol 103 (1021) ◽  
pp. 139-142 ◽  
Author(s):  
L. W. Traub
Keyword(s):  
Vortex Breakdown ◽  
Side Wall ◽  
Vortical Flow ◽  
Navier Stokes ◽  
Wall Effects ◽  
Integral Expression ◽  
Image System ◽  
Tunnel Wall ◽  
Delta Wings ◽  
Side Walls

AbstractAn incompressible method is presented to predict the upwash corrections associated with vortical flow as a result of wind-tunnel side wall effects. An image system is used to simulate the tunnel side walls which are assumed to be solid. An integral expression is formulated, representing the average upwash induced over the wing by the image system. Wall effects may be determined for flows with and without vortex breakdown. Comparisons of the results with upwash predictions from a Navier-Stokes study show close accord. The upwash expression also displayed the ability to successfully predict corrections for flows involving vortex breakdown.

Vortex breakdown location over 65° delta wings empiricism and experiment

2004 ◽  
Vol 108 (1087) ◽  
pp. 475-482 ◽  
Author(s):  
C. E. Jobe
Keyword(s):  
Vortex Breakdown ◽  
Leading Edge ◽  
Sudden Expansion ◽  
Navier Stokes ◽  
Prediction Methods ◽  
Data Sets ◽  
Tunnel Wall ◽  
Delta Wings ◽  
Static Tests ◽  
Static Test

Abstract Thirty-eight data sets from static tests of various 65° delta wings in many water and wind tunnels are compared with four empirical vortex breakdown location prediction methods and the results of two Navier-Stokes computations to assess their range of validity in pitch. Vortex breakdown is the sudden expansion and subsequent chaotic evolution of the otherwise orderly, spiraling, leading-edge vortex flow over the upper surface. Large fluctuations occur in vortex breakdown location at static test conditions making accurate experimental determination difficult. The prediction methods do not account for the seemingly minor geometric details that vary between the models such as thickness, leading-edge bevel angle and radius, trailing-edge bevel angle, sting mounting, instrument housings, etc. These geometric variations significantly affect the position of vortex breakdown and degrade the accuracy of the predictions. The large changes in the flow produced by small geometric changes indicate that an efficient flow control strategy may be possible. Many of the data sets are not corrected for tunnel wall effects, which may account for some of the differences. Data presented herein are as published by the original authors, without additional corrections.

Wind-tunnel wall effects on delta wings

1989 ◽  
Vol 26 (5) ◽  
pp. 403-404 ◽  
Author(s):  
Neal T. Frink
Keyword(s):  
Wind Tunnel ◽  
Wall Effects ◽  
Tunnel Wall ◽  
Delta Wings

Recent developments in delta wing aerodynamics

2004 ◽  
Vol 108 (1087) ◽  
pp. 437-452 ◽  
Author(s):  
I. Gursul
Keyword(s):  
Shear Layer ◽  
Vortex Breakdown ◽  
Delta Wing ◽  
Layer Structure ◽  
Vortical Flow ◽  
Time Lags ◽  
Delta Wings ◽  
Vortex Interactions ◽  
Recent Developments ◽  
Wing Aerodynamics

Abstract Recent developments in delta wing aerodynamics are reviewed. For slender delta wings, recent investigations shed more light on the unsteady aspects of shear-layer structure, vortex core, breakdown and its instabilities. For nonslender delta wings, substantial differences in the structure of vortical flow and breakdown may exist. Vortex interactions are generic to both slender and nonslender wings. Various unsteady flow phenomena may cause buffeting of wings and fins, however, vortex breakdown, vortex shedding, and shear layer reattachment are the most dominant sources. Dynamic response of vortex breakdown over delta wings in unsteady flows can be characterised by large time lags and hysteresis, whose physical mechanisms need further studies. Unusual flow–structure interactions for nonslender wings in the form of self-excited roll oscillations have been observed. Recent experiments showed that substantial lift enhancement is possible on a flexible delta wing.

Tank Side-Wall Effect Evaluated by Using Multi-Body Interaction Computation

2007 ◽  
Author(s):  
W. Y. Duan ◽  
H. Shaheen ◽  
X. B. Chen
Keyword(s):  
Wave Diffraction ◽  
Direct Method ◽  
Side Wall ◽  
Floating Body ◽  
Wall Effects ◽  
Usual Model ◽  
Body Interaction ◽  
Parallel Side ◽  
Side Walls ◽  
Multi Body

It is well known that hydrodynamic first- and second-order loads measured on ships or offshore structures in wave tanks exhibit large scatter compared to the expected results in open sea, due to wave reflections from the side walls. A number of recent works have given theoretical models for diffraction and radiation solutions including side-wall effects. One way consisting of defining a Green function satisfying the boundary condition on two parallel side walls can yield reliable solutions for a floating body of arbitrary geometry in any position of the tank. Unlike previous studies, we evaluate the side-wall effects by directly using the option of multi-body interaction in usual model of wave diffraction and radiation. The tank side-walls are considered as an independent fixed body. The wave diffraction and radiation around a floating body in tanks is solved by taking into account of interaction between the two bodies. The excellent agreement between numerical results of first-order quantities and experimental measurements validates the present method. It is shown that this direct method is very efficient and can be further applied to the case of two side walls in non-parallel position as well as to take into account of bathymetric variation of sea bottom.

Surface shaping to suppress vortex breakdown on delta wings

AIAA Journal ◽  
2000 ◽  
Vol 38 ◽  
pp. 186-187
Author(s):  
S. Srigrarom ◽  
M. Kurosaka
Keyword(s):  
Vortex Breakdown ◽  
Delta Wings ◽  
Surface Shaping

Vortex breakdown over unsteady delta wings and its control

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 571-574
Author(s):  
H. Yang ◽  
I. Gursul
Keyword(s):  
Vortex Breakdown ◽  
Delta Wings

Innovative approaches in the organization of closed waste-free production of organic pork using cultural and natural agricultural land

2020 ◽  
pp. 15-25
Author(s):  
Volodymyr Ivanov ◽  
Andrii Onyshchenko ◽  
Liudmyla Ivanova ◽  
Liudmyla Zasukha ◽  
Valerii Hryhorenko
Keyword(s):  
Agricultural Land ◽  
Side Wall ◽  
Front Wall ◽  
Lower Edge ◽  
Metal Mesh ◽  
Two Phase ◽  
Transparent Plastic ◽  
Pork Production ◽  
Young Pigs ◽  
Side Walls

The mobile house for two-phase litter rearing piglets was developed in the conditions of pasture their housing, the feature of which is that its side walls and roof are made in the form of two similar in shape and length of arched panels. In the back wall of the inner shield is a litter box, a self-feeder for piglets, a feed unit for a sow and a wicket, and in the front wall of the outer shield are doors with a wicket. Along with this, all walls and the roof of the litter box are made of transparent plastic, and the wall located near the self-feeding trough is also made perforated. In addition, the lower edge of the side wall of the inner arch-shaped shield has slides in which the lower edge of the side wall of the outer arc-shaped shield is inserted. A house with transformable fences has been developed to rear the young pigs. The structural feature of the house is the presence on the outside of the walls of the bobbins with a metal mesh edged at the bottom with a flexible sleeve. In order to ensure the conditions of gentle etching of the vegetation cover and to prevent damage to the turf of the pasture, the house can be completed with another type of hedge consisting of two hinged sections with doors on each side of the fence. In addition, the horizontal wings are rigidly attached to the hedge and connected by a metal mesh around the perimeter, the size of the cells of which ensures that the grass is eaten but prevents the turf of the pasture from being undermined. The developed devices for camp-pasture and feeding of maternal stock, suckling pigs, weaning pigs, repair and fattening pigs are well suited for year-round closed non-waste organic pork production using cultural and natural agricultural land. Key words: housing, feeding, devices, sows, piglets, young animals, pasture, organic pork.

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