2 edition of Some effects of shed vortices on the flow fields around stabilizing tail surfaces found in the catalog.
Some effects of shed vortices on the flow fields around stabilizing tail surfaces
Ralph W. Stone
Presented at the 5th Meeting of the Structures and Materials Panel, held in Copenhagen, 29th April to 3rd May 1957.
|Statement||by Ralph W. Stone Jr. and Edward C. Polhamus.|
|Series||Agard report -- 108|
|Contributions||Polhamus, Edward C., Advisory Group for Aeronautical Research and Development. Structures and Materials Panel.|
1. INTRODUCTION. Stability in flight is essential for performance and safety in ski jumping. Stability in roll is concerned with lateral stability around the longitudinal (x) axis (Figure 1; Table 1), and stability in yaw (weathercock stability) pertains to directional stability about the normal (z) axis with aerodynamic static stability in pitch 2, it is desirable that the ski jumper Cited by: 5. The main flow features around a vertical cylindrical pile exposed to a steady current on a plane bed are the horseshoe vortex formed in front of the pile, the lee-side vortices (usually in the form of vortex shedding), contracted streamlines around the sides of the pile and the down-flow in front of the pile due to deceleration of the by:
At m s −1, the tail is widely spread with the circulation of the tail vortices being stronger compared with and m s −1 (figure 6 c). However, the reason that the circulation of the tail vortices at the lowest speed is higher than at the other speeds may not only be due to a wider spread of the tail, but also to a higher body by: The flow field around the swimmers during steady swimming is visualized by the q-criterion, velocity vectors and contours of the out-of-plane vorticity in Figure 4, Figure 5 and Figure 6. Here, Figure 4 a,b shows the 3-D structure of the wake of the swimmer by plotting the isosurfaces of the q-criterion [ 40 ] for the near ground swimmer and.
Full text of "DTIC ADP Problems Associated with the Aerodynamic Design of Missile Shapes" See other formats PROBLEMS ASSOCIATED WITH THE AERODYNAMIC DESIGN OF MISSILE SHAPES Oi rp c: Jack N. Nielsen Nielsen Engineering ^ Research, Inc. Mountain View, CA , Abstract “"The purpose of the paper is to discuss ^^ /anous trends in the design of tactical ^^'.issiles . Rainbow trout consume less oxygen in turbulence: the energetics of swimming behaviors at different speeds. Kármán gaiting consists of sensing and moving with the lateral component of the sinusoidal flow established by vortices shed downstream from a cylinder The effects of flow turbulence on the behavior and distribution of fish. by:
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Artist's impression of the flow behind a steadily swimming saithe. The tail blade is moving to the left and in the middle of the stroke. At the end of each half-stroke, a column vortex is left behind when the tail blade changes direction.
Tail-tip vortices are shed dorsally and ventrally when the tail. Weitere Anwendungsmöglichkeiten der aktiven Steuerungstechnologie. Authors; Authors and affiliations Some Effects of Shed Vortices on the Flow Fields around Stabilizing 7äil Surfaces.
AGARD Rep. Hafer X., Sachs G. () Weitere Anwendungsmöglichkeiten der aktiven Steuerungstechnologie. In: Flugmechanik. Hochschultext. Author: Xaver Hafer, Gottfried Sachs. U nderstanding the development and growth of wingtip vortices over lifting surfaces is an ongoing research topic both in academia and industry.
From an academic perspective, fundamental open questions remain, such as the possible relaminarization of the vortex as it is shed from the wing  and the origin of meandering [2 – 4], the low-frequency movement of the vortex core, and the evolution Cited by: In this study of vortex shedding, destruction of the vortex street and drag reduction of a circular cylinder near a moving ground have employed a numerical Lagrangian technique, called the vortex method.
All the simulations are carried out with a high value of the Reynolds number of ×10 5 using turbulence modeling. The present numerical results are in good agreement with the limited amount of.
A brimmed-diffuser augmented turbine (called a wind lens turbine: WLT) actively uses vortices around the brim to enhance its power output. However, the vortices are usually unstable and asymmetric.
This study attempted to stabilize the vortices to enhance the power output of a by: 1. Approximating the complexity of natural locomotor conditions provides insight into the diversity of mechanisms that enable animals to successfully navigate through their environment.
When exposed to vortices shed from a cylinder, fishes hold station by adopting a mode of locomotion called the Kármán gait, whereby the body of the fish displays large, lateral oscillations and the tail-beat Cited by: The influence of spanwise flow on the development and stabilization of leading-edge vortices (LEVs) on a foil (without rotational acceleration) has been investigated.
The influence of a wake-mounted splitter plate on the flow around a surface-mounted circular cylinder of finite height was investigated experimentally using a low-speed wind tunnel.
The effect of nonuniform flow (linear shear) with shear intensity (K) ranging from 0 to on flow field characteristics has been examined using iso-Q surfaces and streamline plots.
Hu et al.  experimentally investigated the effect of corner radius on the near-wake flow of an isolated cylinder at Re = and For the rounded corner cylinder, the wake vortices are. The results showed that with high tail/wing circulation ratios (high tail downloads), the tail and wing vortices interacted so as to leave very little recognizable vortex structure after a.
Localization of Wing-Flow Separation 69 T. Feistel* and S. Anderson'[" NASA Ames Research Center, Moffett Field, Calif. and R. Kroeger_ ARO, Inc., Tullahoma, Tenn. Studies have been made on several wing leading-edge modifications applicable at present to single-engine light aircraft, which produce stabilizing vortices at stall and beyond.
On all subsonic wings, there is a tendency for a secondary flow to develop from the high-pressure region below the wing around the wingtip to the relatively low-pressure region on the upper surface (Fig. (b)). This is part of the formation of trailing vortices.
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Another place that is bad on some ships is just aft of the horizontal tail and right at the rudder. If, for instance. you wanted to probe the wing root flow you go to the area of the wing root say just above or below the wing and say half way back on the chord and drill a 1/16th inch diameter hole in the skin, through that hole you insert your.
passes the region of the tails for a body-tail configuration. Some of the effects of the forebody-shed vortices are discussed in references 2 and 3. This is a complex problem that is still of concern and investigations in this area continue. The effects of Mach number and body length on the pitch characteristics are.
In an important respect, Fig. B is misleading, because it cannot depict the unsteady nature of the flow field. The vortices are, in fact, shed alternately in a similar fashion to the von Kármán vortex street behind a circular cylinder (see Section ).
It can be also seen in the figure (showing the configuration for enhancing downforce) that the vortices behind the Gurney flap deflect the flow downstream upwards.
Flow and scour around a vertical cylinder exposed to current are investigated by using a three-dimensional numerical model based on incompressible Reynolds-averaged Navier–Stokes equations. The model incorporates (i) k - ω turbulence closure, (ii) vortex-shedding processes, (iii) sediment transport (both bed and suspended load), as well as Cited by: These studies show that the pressure distribution across the body causes the vortices shed behind the body to be deflected upwards on the leeward side and downwards on the windward side.
A novel set of serrated-planform lifting surfaces produce unexpectedly high lift coefficients at moderate to high angles-of-attack. Each serration, or tooth, is designed to shed a vortex. The interaction of the vortices greatly enhances the lifting capability over an extremely large operating range.
Variations of the invention use serrated-planform lifting surfaces in planes different than Cited by:. The Simpson et al. device is effective at preventing vortices that cause substrate transport for a large range of river flow conditions and bed substrate materials because it fundamentally alters the way the river flows around the pier.
FIG. 5 shows flow around the Simpson et al. device streamlined bridge pier fairing that remains attached without the formation of vortices. The convex-concave pier fairing nose Author: Roger Lyndon Simpson, Gwibo Byun.A series of instantaneous velocity vectors in a shear flow around a tail building at half body height during one period of vortex–ehedding process One evidence of the strong dependence of the flow on Karman vortex shedding can be seen from the plot of drag Cited by: During the course of the final half of the upstroke, wingtip vortices merge with the tail vortices (figure 5; mean tail wake-span is 27 mm during mid-upstroke).
At m s −1, the downstroke shows similar features as that of m s −1 (figure 4 b), although the wing root vortices appear to be present for a larger portion of the Cited by: