scholarly journals HYDRODYNAMIC ASPECTS OF DESIGN AND ATTACHMENT OF A BACK-MOUNTED DEVICE IN PENGUINS

1994 ◽  
Vol 194 (1) ◽  
pp. 83-96 ◽  
Author(s):  
R Bannasch ◽  
RP Wilson ◽  
B Culik
Keyword(s):  
Wind Tunnel ◽  
The Body ◽  
Hydrodynamic Resistance ◽  
Water Tank ◽  
Body Contour

Wind tunnel and water tank experiments were carried out on a penguin model in order to optimise the shape and attachment of a back-mounted datalogger. Device-induced turbulence was minimised when the unit was placed in the most caudal position. Drag was further reduced by shaping the device to match the body contour. The hydrodynamic resistance of the package could be reduced by 65 % compared with an earlier unit. These results are discussed together with results from new studies on kinematics and energetics of underwater swimming of live instrumented penguins.

Preoperative and Postoperative Management of the Body Contour Patient

1996 ◽  
Vol 16 (4) ◽  
pp. 218-223
Author(s):  
R. Rohrich ◽  
P. B. Fodor ◽  
J. J. Petry ◽  
P. Vash
Keyword(s):  
Postoperative Management ◽  
The Body ◽  
Body Contour

Incipient Separation Near Corners

2018 ◽  
Author(s):  
Anatoly I. Ruban
Keyword(s):  
Corner Point ◽  
Analytic Form ◽  
The Body ◽  
Recirculation Region ◽  
Body Contour ◽  
Concave Corner ◽  
Attached Flow ◽  
Surface Deflection ◽  
Interaction Problem ◽  
Incipient Separation

Chapter 4 analyses the transition from an attached flow to a flow with local recirculation region near a corner point of a body contour. It considers both subsonic and supersonic flow regimes, and shows that the flow near a corner can be studied in the framework of the triple-deck theory. It assumes that the body surface deflection angle is small, and formulates the linearized viscous-inviscid interaction problem. Its solution is found in an analytic form. It also presents the results of the numerical solution of the full nonlinear problem. It shows how, and when, the separation region forms in the boundary layer. In conclusion, it suggests that in the subsonic flow past a concave corner, the solution is not unique.

scholarly journals Magnitude integration in the Archerfish

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tali Leibovich-Raveh ◽  
Ashael Raveh ◽  
Dana Vilker ◽  
Shai Gabay
Keyword(s):  
Animal Model ◽  
Grocery Store ◽  
The Body ◽  
Water Tank ◽  
Comparison Task ◽  
Magnitude Comparison ◽  
Mathematical Abilities ◽  
In The Wild ◽  
Numerical Magnitudes ◽  
Shortest Queue

AbstractWe make magnitude-related decisions every day, for example, to choose the shortest queue at the grocery store. When making such decisions, which magnitudes do we consider? The dominant theory suggests that our focus is on numerical quantity, i.e., the number of items in a set. This theory leads to quantity-focused research suggesting that discriminating quantities is automatic, innate, and is the basis for mathematical abilities in humans. Another theory suggests, instead, that non-numerical magnitudes, such as the total area of the compared items, are usually what humans rely on, and numerical quantity is used only when required. Since wild animals must make quick magnitude-related decisions to eat, seek shelter, survive, and procreate, studying which magnitudes animals spontaneously use in magnitude-related decisions is a good way to study the relative primacy of numerical quantity versus non-numerical magnitudes. We asked whether, in an animal model, the influence of non-numerical magnitudes on performance in a spontaneous magnitude comparison task is modulated by the number of non-numerical magnitudes that positively correlate with numerical quantity. Our animal model was the Archerfish, a fish that, in the wild, hunts insects by shooting a jet of water at them. These fish were trained to shoot water at artificial targets presented on a computer screen above the water tank. We tested the Archerfish's performance in spontaneous, untrained two-choice magnitude decisions. We found that the fish tended to select the group containing larger non-numerical magnitudes and smaller quantities of dots. The fish selected the group containing more dots mostly when the quantity of the dots was positively correlated with all five different non-numerical magnitudes. The current study adds to the body of studies providing direct evidence that in some cases animals’ magnitude-related decisions are more affected by non-numerical magnitudes than by numerical quantity, putting doubt on the claims that numerical quantity perception is the most basic building block of mathematical abilities.

Morphological characterization of Trichotylenchus gorganiensis n. sp. (Nematoda: Dolichodoridae) and photomicrographs of several other species of the subfamily Telotylenchinae Siddiqi, 1960

Zootaxa ◽  
2018 ◽  
Vol 4526 (4) ◽  
pp. 447
Author(s):  
REZA GHADERI ◽  
AKBAR KAREGAR ◽  
ESMAEIL MIRAEIZ
Keyword(s):  
New Species ◽  
Morphological Characterization ◽  
The Body ◽  
Morphometric Data ◽  
Tail Region ◽  
Body Contour ◽  
Closely Related Species ◽  
Pharyngeal Bulb ◽  
Anal Sac

Trichotylenchus gorganiensis n. sp. is described and illustrated based on morphological and morphometric data. The new species is characterized by its 760–1073 µm long body, conoid-rounded lip region continuous with the body contour and bearing 5–7 fine striae, 22.0–24.5 µm long stylet, basal pharyngeal bulb offset or slightly overlapping intestine, post-anal sac extending 50–73 % of the tail region, and cylindrical or subclavate tail with a striated terminus. Differences of the new species from the closely related species T. astriatus, T. astriatoides, T. changlingensis and T. papyrus are discussed. Photomicrographs and several taxonomic notes on 13 other species of Telotylenchinae, collected from Iran, are provided. 

Determining the nominal body contour image using wideband millimeter-wave radar for characterizing person-worn threats

2021 ◽  
pp. 1-7
Author(s):  
Mohammad M. Tajdini ◽  
Carey M. Rappaport
Keyword(s):  
Millimeter Wave ◽  
Cross Section ◽  
Homeland Security ◽  
Bilateral Symmetry ◽  
The Body ◽  
Airport Security ◽  
Screening Process ◽  
Body Contour ◽  
Millimeter Wave Radar ◽  
Wave Radar

Abstract Precise characterization of concealed person-worn objects will speed up the passenger screening process by reducing the rate of nuisance alarms, while also enhancing the airport security imaging systems. This paper presents an automatic, real-time method for wideband millimeter-wave radar identification of the nominal surface contours of the human body – even with affixed foreign objects or when a segment of the body cross-section is not captured by the radar – without relying on the body's bilateral symmetry. The developed method is verified experimentally when applied to the actual images generated by a laboratory airport scanning prototype developed recently by the US Department of Homeland Security (DHS). Our method uses the noisy collection of radar cross-section reflectivity data to extract the main contours and estimates the nominal body surface cross-sections through fitting a small-term Fourier series of circumferential variation. This is a necessary step for accurate characterizing of concealed terrorist threat objects affixed to the body.

scholarly journals Full-Span Flying Wing Wind Tunnel Test: A Body Freedom Flutter Study

Fluids ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 34
Author(s):  
Pengtao Shi ◽  
Jihai Liu ◽  
Yingsong Gu ◽  
Zhichun Yang ◽  
Pier Marzocca
Keyword(s):  
Wind Tunnel ◽  
Theoretical Analysis ◽  
Mass Balance ◽  
Degrees Of Freedom ◽  
Wind Tunnel Test ◽  
Suspension System ◽  
The Body ◽  
Structural Dynamic ◽  
Flutter Speed ◽  
Theoretical Results

Aiming at the experimental test of the body freedom flutter for modern high aspect ratio flexible flying wing, this paper conducts a body freedom flutter wind tunnel test on a full-span flying wing flutter model. The research content is summarized as follows: (1) The full-span finite element model and aeroelastic model of an unmanned aerial vehicle for body freedom flutter wind tunnel test are established, and the structural dynamics and flutter characteristics of this vehicle are obtained through theoretical analysis. (2) Based on the preliminary theoretical analysis results, the design and manufacturing of this vehicle are completed, and the structural dynamic characteristics of the vehicle are identified through ground vibration test. Finally, the theoretical analysis model is updated and the corresponding flutter characteristics are obtained. (3) A novel quasi-free flying suspension system capable of releasing pitch, plunge and yaw degrees of freedom is designed and implemented in the wind tunnel flutter test. The influence of the nose mass balance on the flutter results is explored. The study shows that: (1) The test vehicle can exhibit body freedom flutter at low airspeeds, and the obtained flutter speed and damping characteristics are favorable for conducting the body freedom flutter wind tunnel test. (2) The designed suspension system can effectively release the degrees of freedom of pitch, plunge, and yaw. The flutter speed measured in the wind tunnel test is 9.72 m/s, and the flutter frequency is 2.18 Hz, which agree well with the theoretical results (with flutter speed of 9.49 m/s and flutter frequency of 2.03 Hz). (3) With the increasing of the mass balance at the nose, critical speed of body freedom flutter rises up and the flutter frequency gradually decreases, which also agree well with corresponding theoretical results.

In the Wind Tunnel Simulation Defroster Control Study

2013 ◽  
Vol 380-384 ◽  
pp. 191-194
Author(s):  
Qin Yu Yang ◽  
Jin Bo Yao ◽  
Yue Ming Yang ◽  
Xue Wei Liu
Keyword(s):  
Wind Tunnel ◽  
External Environment ◽  
Aerodynamic Performance ◽  
The Body ◽  
Flight Safety ◽  
Aircraft Icing ◽  
Real Situation ◽  
Wind Tunnel Simulation ◽  
Performance Deterioration ◽  
Control Study

Aircraft in flight, such as supercooled water droplets encountered icing conditions suitable for the external environment, the relevant parts of the body will freeze, making the aircraft's aerodynamic performance deterioration, severe endanger flight safety, in addition, the aircraft parked in the open winter months , there will be icing, you need to clean up before takeoff. We should grasp the mechanism of aircraft icing, environmental factors and easy to freeze parts of the body. This paper presents a simulation using the wind tunnel icing device icing wind tunnel simulations can reproduce the real situation of aircraft icing, for guiding practice and got good results.

scholarly journals Effect of water medium upon the process of ore disintegration in wet self-grinding mills

2019 ◽  
Vol 109 ◽  
pp. 00058
Author(s):  
Vitalii Monastyrskyi ◽  
Serhii Monastyrskyi ◽  
Borys Mostovyi
Keyword(s):  
Aquatic Environment ◽  
Experimental Studies ◽  
The Body ◽  
Angle Of Repose ◽  
Hydrodynamic Resistance ◽  
Uniform Structure ◽  
Water Medium ◽  
Large Piece ◽  
Grinding Mills ◽  
Expansion Force

This article presents the results of theoretical and experimental studies on the processes of destruction ore in wet self-grinding mills under the influence of the aquatic environment on it. The equivalent circuit for determining the stress-strain state of a large piece (ball) exposed to the load at an angle of repose of the material in motion are justified. A uniformly distributed pressure acts on the body of arbitrary shape, depending on the hydrostatic pressure of the pulp inside the drum and the force of hydrodynamic resistance). It is assumed that a large piece has the shape of a sphere with a uniform structure, but in some of its parts there are cavities filled with an incompressible fluid. Under the action of these forces inside the cavity wedging effects of water occur, the effect of which on the strength ores depends on the expansion force and the angle of the micro crack. The experimental researches are done under laboratory and industrial conditions. It was established that the disintegration of kimberlitic ore in MMC is significantly influenced by the characteristics of the aquatic environment pH and Eh, the values of which vary from 3.2 to 7.0 and from -500 to +1020 mV.

Strouhal numbers of rectangular cylinders

1982 ◽  
Vol 123 ◽  
pp. 379-398 ◽  
Author(s):  
Atsushi Okajima
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Velocity Distribution ◽  
Flow Pattern ◽  
Strouhal Number ◽  
Vortex Shedding ◽  
Water Tank ◽  
Height Ratio ◽  
Rectangular Cylinders ◽  
Good Agreement

Experiments on the vortex-shedding frequencies of various rectangular cylinders were conducted in a wind tunnel and in a water tank. The results show how Strouhal number varies with a width-to-height ratio of the cylinders in the range of Reynolds number between 70 and 2 × l04. There is found to exist a certain range of Reynolds number for the cylinders with the width-to-height ratios of 2 and 3 where flow pattern abruptly changes with a sudden discontinuity in Strouhal number. The changes in flow pattern corresponding to the discontinuity of Strouhal number have been confirmed by means of measurements of velocity distribution and flow visualization. These data are compared with those of other investigators. The experimental results have been found to show a good agreement with those of numerical calculations.

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