Experimental evidence of macroscopic spatial quantization of angular momentum in rotating helium

Deroyon, M.J.; Deroyon, J. P.; Ray, M. Le

doi:10.1016/0375-9601(73)90183-7

Cited by 7 publications

(4 citation statements)

References 5 publications

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“…It is, moreover, by coupling this law with the concept of that preferential angle, formed by helicoidally vortices with their axes, that the authors of the papers referred to in [1] and [2] interpreted the discontinuous angular behaviour of these vortex systems in liquid helium [1, 2 and 19].…”

Section: Resultsmentioning

confidence: 99%

“…: preferential angle associated with the whole numbers ℓ and m ℓ, m : whole numbers such as ℓ ≥ m β : apex (included) angle h : height of the ogive of revolution R : radius of the base of the ogive of revolution I : incidence V o : speed of the flow to infinity upstream Re : Reynolds' number ω 1 : the main or interior intervortex angle ω 2 : the secondary or exterior intervortex angle α : the main intervortex angle present on the upper surface of delta or gothic wings…”

Section: Notations θ ℓMmentioning

confidence: 99%

“…The concept of a preferential angle was introduced for the first time in 1972 by M. LE RAY and his colleagues and stems from their studies of liquid helium [1,2]. These angles, which have the following relatively simple analytic formula : A particularly high number of studies have been carried out to date into delta or gothic wings and into some combinations of such components that form more or less simple slender bodies; they have dealt as much with the development of approximate theories as with the definition of models specifying vortex lift per unit area.…”

Section: Introduction Reynoldsmentioning

confidence: 99%

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Experimental Study by Visualisation of Behavioural Properties of Vortex Structures on the Upper Surface of an Ogive of Revolution ? 52°

Abene¹

2014

IJMEA

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A large number of studies of flow visualisations, developed on the upper surface of delta or gothic wings and on that of ogives of revolution, have been carried out in the wind tunnel of the Valenciennes University aerodynamics and hydrodynamics laboratory (LAH). These studies have provided a better understanding of the development and the positioning of vortex structures and have enabled, in particular, the preferential nature of intervortex angles, thereby defined, to be determined on a wide range of Reynolds. This paper concerns in particular the study by visualisations of the behavioural properties on the upper surface of an ogive of revolution having an apex angle of 68.6° at a low angle of attack and conducted at variable speeds. It has been noted that variations in speed have no influence at all on the behavioural properties of the development of vortex structures whereas, by contrast, changes to the angles of incidence do indeed strongly influence that development. The study of the ascent of the vortex breakdown at high angles of attack has revealed original behavioural properties which find expression notably in the discontinuous evolution, in terms of the apex angle, of those angles of attack which define the beginning and the end of the ascent of this vortex breakdown. These properties undoubtedly reflect those already observed in similar studies carried out on delta and gothic wings and on cones. However, no current theory seems to be able to provide a straightforward explanation of these phenomena.

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Section: Resultsmentioning

confidence: 99%

Section: Notations θ ℓMmentioning

confidence: 99%

Section: Introduction Reynoldsmentioning

confidence: 99%

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Experimental Study by Visualisation of Behavioural Properties of Vortex Structures on the Upper Surface of an Ogive of Revolution ? 52°

Abene¹

2014

IJMEA

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“…. it has to be checked, because of missing data, or of multiple declarations: hence work is done by Insee to impute missing data (Deroyon 2013) and to deal with multiple declarations, . not all information needed to produce the structural business statistics is available in these files, and additional information has to be obtained elsewhere.…”

Section: An Intensive Use Of Administrative Data Combined With a Surveymentioning

confidence: 99%

Statistical Estimators Using Jointly Administrative and Survey Data to Produce French Structural Business Statistics

Gros

2015

Journal of Official Statistics

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Using as much administrative data as possible is a general trend among most national statistical institutes. Different kinds of administrative sources, from tax authorities or other administrative bodies, are very helpful material in the production of business statistics. However, these sources often have to be completed by information collected through statistical surveys. This article describes the way Insee has implemented such a strategy in order to produce French structural business statistics. The originality of the French procedure is that administrative and survey variables are used jointly for the same enterprises, unlike the majority of multisource systems, in which the two kinds of sources generally complement each other for different categories of units. The idea is to use, as much as possible, the richness of the administrative sources combined with the timeliness of a survey, even if the latter is conducted only on a sample of enterprises. One main issue is the classification of enterprises within the NACE nomenclature, which is a cornerstone variable in producing the breakdown of the results by industry. At a given date, two values of the corresponding code may coexist: the value of the register, not necessarily up to date, and the value resulting from the data collected via the survey, but only from a sample of enterprises. Using all this information together requires the implementation of specific statistical estimators combining some properties of the difference estimators with calibration techniques. This article presents these estimators, as well as their statistical properties, and compares them with those of other methods.

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2013

Innovation Engineering: The Power of Intangible Networks

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Experimental evidence of macroscopic spatial quantization of angular momentum in rotating helium

Cited by 7 publications

References 5 publications

Experimental Study by Visualisation of Behavioural Properties of Vortex Structures on the Upper Surface of an Ogive of Revolution ? 52°

Experimental Study by Visualisation of Behavioural Properties of Vortex Structures on the Upper Surface of an Ogive of Revolution ? 52°

Statistical Estimators Using Jointly Administrative and Survey Data to Produce French Structural Business Statistics

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