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  • Fluid Mechanics and Thermodynamics  (16)
  • 42.75
  • 1950-1954  (26)
  • 1953  (10)
  • 1950  (16)
  • 1
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.32 (1953) nr.18 p.203
    Publication Date: 2013-03-01
    Description: COPROMORPHIDAE Meyrick, 1905, Journ. Bombay Nat. Hist. Soc, vol. 16, p. 606. This small family represents a natural group with clearly marked characters, and is easy of descrimination. It inhabits tropical regions of Asia and extends through the Papuan region over the whole Pacific. The last mentioned region might be the country of origin of this group, as genera with peculiar and possibly archaic characters have been recorded from the Pacific Islands; some of those species are distinguished by an exceptionally large size. One of the interesting points with regard to the family is its possible place in the system. The long-ciliate or pectinate antennae, the neuration, and the complicated genital apparatus of the male seem to indicate an affinity with the Tineoidea. The general facies, however, is divergent to some extent, while the presence of a cubital pecten on the hind wings fundamentally discriminates this family from all the Tineoidea sensu stricto. When describing the family, Meyrick suggested that the cubital pecten might point towards an affinity with the Tortricoidea ; this relation, however, is not supported by any other characters. He further surmised that the Copromorphidae would be nearest allied to the Xyloryctidae ; in my opinion this surmise is devoid of any ground. Later Meyrick tried to combine with the Copromorphidae two other groups of "Tineina" that also are in possession of a cubital pecten, viz., the family Orneodidae, and the genus Hypertropha Meyr. The relation of the former with the Copromorphidae, however, is problematic, and deserves further proofs, while Hypertropha has in my opinion nothing in common with the family concerned, except for the
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 2
    Publication Date: 2013-03-01
    Description: Contents ι. Introduction..............I 2. Systematics (a, The correct name of the genus p. 4; b, Diagnostic characters of the species and subspecies p. 6; c, Abbreviations p. 9; d, Key to the species and subspecies p. 10; e, Survey of the species and subspecies p. 11; f, Disregarded specimens p. 30; g, Wilcoxon tests for the difference between certain measurements in allied subspecies p. 31; h, Early stages p. 36; i, The species concept in Nyctalemon p. 37).......... 3. Biology............... 38 4. Distribution.............. 43 5. Evolution............... 46 6. Bibliography.............. 52 1. INTRODUCTION In November 1949 the late Professor Dr. L. J. Toxopeus of Bandung, Java, sent me a specimen of Nyctalemon for identification, but neither with the help of our collection, nor with the current literature did I succeed in ascertaining the correct name of this insect. On the contrary it appeared that, though the described forms of this genus clearly were of different value, viz., partly good species, partly geographical subspecies representing these species in restricted areas, no satisfactory division of the genus into species and subspecies had been given. Thus, Seitz' classification of the known forms into four species of which three are polytypic proved to make no sense. Therefore I resolved to study the genus more closely. In the ensuing correspondence Toxopeus gave me the benefit of his experience by providing references to relevant literature and quotations from
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 3
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.32 (1953) nr.9 p.87
    Publication Date: 2013-03-01
    Description: I have to thank Dr. H. C. Blöte of the Leiden Museum of Natural History for his kindness to entrust me with a number of Carabidae from Indonesia for identification. A few species appear to be new to science; the descriptions follow below. One genus, Horniulus Jedl., is new to the whole of the Malay Archipelago, and another, Bembidion Latr., is new to Sumatra. Of the latter genus there are already a couple of species known from Java. I am much obliged to Mr. E. B. Britton of the British Museum, who carefully compared a few species with specimens in the collections of the British Museum and in Andrewes' collections. The type specimens are in the Leiden Museum. Oxygnathopsis gen. nov. (fig. 1 f) (Andrewes (1938, p. 196) described Oxygnathus javanus upon a single specimen from Java. With regard to the proper genus Andrewes was not absolutely sure because of a number of important differences, but before introducing a new genus he preferred to wait till more material was available. In the sending of the Leiden Museum I found a second specimen, which shows the same characteristics as the specimen described by Andrewes, so that in my opinion a new genus is desirable. The two genera are to be distinguished as follows: 1 (2) Head with the clypeus bisetose, two setae on each side over the eyes, facial carinae and sulci present; prothorax with two lateral setae on each side. Range: Assam and Burma.........Oxygnathus Dej. 2 (1) Clypeus without setae, one supra-orbital seta, the front seta is wanting, no facial Fig. 1. a, Coptodera flavipes sp. n., left elytron; b, Horniulus quadrimaculatus sp. n.,
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 4
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.32 (1953) nr.6 p.49
    Publication Date: 2013-03-01
    Description: I. Attacus dohertyi dammermani nov. subspec. (Plate II) Large, apex of fore wing moderately produced, general coloration of wings, head, notum including patagia, and abdomen rather light reddish brown, several intersegmental folds between the abdominal tergites blackish. In both wings the terminal area somewhat lighter, more yellowish brown, in apex of fore wing grading into yellowish. Hind wing with the apical area markedly reddish. In fore wing the dark apical spot and red dash weak, submarginal line practically wanting, in hind wing a somewhat undulating submarginal dark line well developed. Postmedian band in both wings strongly serrate, but not bent inwards. Antemedian band in both wings less distinct, not serrate, in fore wing angled on base of v2, in hind wing curved inwards. The vitreous patches in both wings very large, guttiform by having the base curved outwards, the basal angles rounded, and the top elongated and pointed towards the postmedian band. In both wings with two additional vitreous patches which are in fore wing slightly larger than in hind wing. In hind wing the lower patch communicates with the interior black border of the postmedian band. All these spots bordered by a black margin. The interior orange yellow border, so obvious in many dohertyi specimens, is wanting or indicated by some inconspicuous traces only. Underside corresponding with upperside, the outer half very light, as in atlas, but the subterminal markings in both wings practically wanting or obsolete. Lateral markings of abdomen much less developed than in atlas. I ♀, 25 cm, holotype, W. Sumba, IV. 1925, labelled Dammerman, Sumba Exp., in Museum Leiden. 2. THE SPECIES OF THE GENUS Attacus L. IN THE FAR EAST.
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 5
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.32 (1953) nr.3 p.31
    Publication Date: 2013-03-01
    Description: Eine Bestimmungssendung des Deutschen Entomologischen Institutes veranlasste mich, die Systematik der asiatischen Coenochilus zu studieren. Die Museen Leiden, Berlin und München und die Herren Frey, Haberäcker, Klapperich und van Nidek stellten mir ihr Material zur Verfügung; Herr Reichert des Museums Dresden und Herr Ruter des Museums Paris gaben bereitwillig Auskunft über Typen ihrer Museen. Ihnen alien sowie den Herren Prof. Dr. Sachtleben, Prof. Dr. Delkeskamp, Dr. C. de Jong, Dr. H. C. Blöte, Dr. Forster, H. Freude, P. Müller und St. von Breuning danke ich bestens für ihre Hilfe. Als Ergebnis meiner Studien veröffentliche ich hier die Beschreibung zweier neuer Arten und des ♂ von C. leopoldi Bourg. sowie eine aus der Arrow'schen Tabelle in der Fauna of British India weiterentwickelte Bestimmungstabelle aller asiatischen Arten. 1. Der Katalog von Junk-Schenkling Pars 72 aus 1921 ist auf Seite 366 f. durch folgende Arten zu ergänzen: assmuthi Wasmann, Wiener Ent. Zeit., vol. 37, 1918, S. 19. bifoveolatus Fairmaire, Ann. Soc. Ent. Fr., 1888, S. 344. leopoldi Bourgoin, Mem. Mus. Roy. H.N. Belg., 1933, Voyage Leopold, vol. IV fasc. 9, Col. II, S. 31. leveillei Nonfried, Berl. Ent. Zeit., 1891, S. 372, der nach Arrow kein Pilinurgus ist. obesus Wasmann, Wiener Ent. Zeit., vol. 37, 1918, S. 21. obscurus Westwood, Tijdsch. v. Ent., vol. 26, 1883, S. 62-65. platycerus Gerstäcker, von S. 368 des Kat. (1883). sumatranus Westwood, Tijdsch. v. Ent., vol. 26, 1883, S. 62-65. uncinatipes Moser, D. Ent. Zeit., 1915, S. 596.
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 6
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.32 (1953) nr.5 p.43
    Publication Date: 2013-03-01
    Description: Some time ago I was asked to identify a fossil coleopteron which had been found in the drill cuttings of an oil well in the Southern part of Sumatra. As the fossil is only a few millimetres long it may be mentioned as an amazing fact that so small an object has been found during rather rough work like oil drilling. The details of the locality as given by Mr. A. Wright Jr. of the N.V. Standard-Vacuum Petroleum Maatschappij are as follows: "The well is one of our Kaja wells, a wildcat well located 3.3 kilometres N. 300 E. from the northeast edge of the Djirah oilfield. The drill cutting was obtained from a depth of 1930 feet subsea. Although, in drill cuttings, there is a certain measure of uncertainty as to the exact level of derivation, we have sufficient evidence to be sure that the fossil actually derives from this depth. The age is Tertiary-e; it occurs below beds of Baturadja stage age, but 200 feet above a lepidocyclina-bearing horizon. The fossil occurs in a shale interval of a formation which is generally non-fossiliferous; conditions were presumably marine, but either oligotrophe or toxic; the water at the time of deposition was shallow." The fossil is pyritized, dark bronze-greyish in colour. It is nearly free from substrate, though in some crevices a light grey, rather soft, somewhat fattish substance is found which can be taken away rather easily. The fossil was sent to the Rijksmuseum van Natuurlijke Historie at Leiden, mounted in a small box on a slide, pasted to the bottom with tragacanth. During the studies it was left in the small box, and kept in an exsiccator to preserve the fossil against deterioration by atmospheric influence.
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 7
    Publication Date: 2019-07-12
    Description: The present status of available information relative to the prediction of shock-induced boundary-layer separation is discussed. Experimental results showing the effects of Reynolds number and Mach number on the separation of both laminar and turbulent boundary layer are given and compared with available methods for predicting separation. The flow phenomena associated with separation caused by forward-facing steps, wedges, and incident shock waves are discussed. Applications of the flat-plate data to problems of separation on spoilers, diffusers, and scoop inlets are indicated for turbulent boundary layers.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-L53I16a
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  • 8
    Publication Date: 2019-06-28
    Description: The trajectories of droplets in the air flowing past NACA 65(1)-208 airfoil and an NACA 65(1)-212 airfoil, both at an angle of attack of 4 degrees, were determined. The amount of water in droplet form impinging on the airfoils, the area of droplet impingement, and the rate of droplet impingement per unit area on the airfoil surface affected were calculated from the trajectories and are presented. The amount, extent, and rate of impingement of the NACA 65(1)-208 airfoil are compared with the results for the NACA 65(1)1-212 airfoil. Under similar conditions of operation, the NACA 65(1)-208 airfoil collects less water than the NACA 65(1)-212 airfoil. The extent of impingement on the upper surface of the NACA 65(1)-208 airfoil is much less than on the upper surface of the NACA 65(1)-212 airfoil, but on the lower surface the extents of impingement are about the same.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TN-2952
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  • 9
    Publication Date: 2019-06-28
    Description: The condensation pressure of air was determined over the range of temperature from 60 to 85 K. The experimental results were slightly higher than the calculated values based on the ideal solution law. Heat of vaporization of oxygen was determined at four temperatures ranging from about 68 to 91 K and of nitrogen similarly at four temperatures ranging from 62 to 78 K.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TN-2969
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  • 10
    Publication Date: 2019-06-28
    Description: The heat requirements for the icing protection of two radome configurations have been studied over a range of design icing conditions. Both the protection limits of a typical thermal protection system and the relative effects of the various icing variables have been determined. For full evaporation of all impinging water, an effective heat density of 14 watts per square inch was required. When a combination of the evaporation and running wet surface systems was employed, a heat requirement of 5 watts per square inch provided protection at severe icing and operating conditions.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-E53A22
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  • 11
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.31 (1950) nr.6 p.63
    Publication Date: 2013-03-01
    Description: Part of the butterfly collection of Mr. P. Zondervan, who died in a Japanese camp, was saved from destruction during the Japanese occupation and the post-war troubles and finally came into my hands. The material is for the greater part still in an excellent condition and contains many interesting forms. The number of specimens is small, as it was Mr. Zondervan's habit to mount only one pair of any new species he collected. The bulk so remained in papers and these all got lost. Here follows an account of some interesting Pieridae. Appias (paulina) urania (Wall.) Tachyris urania, Wallace, "Eastern Pieridae", Trans. ent. Soc. 6 (3) 3 (1867), Tondano, mountains of N. Celebes (♂). Appias urania, Martin, D. ent. Zeits. Iris, 91, 1919. 1 ♂, Tondano, 17.7.1939, 1 ♀, Tondano, 9.1937; 1 ♂, var. albata Hopff., Tondano, 22.12.1939. The ♀ seems to be very rare, though it shows up in rather good numbers in other places of the paulina area in the favourable season, which is at the end of the wet monsoon. It would have been waste of paper to mention these captures, were it not that Mr. Zondervan captured another ♂ specimen of the paulina complex which is so deviating from the above that anybody first seeing it would conceive it as belonging to a distinct species. It represents the leis (Hbn.) group of paulina (Cram.) in the Celebes district, just as urania Wall., together with some local races from the Lesser Sunda Is., is the general representative in the Archipelago. In other words, there has been some overlapping in Celebes, and one more species duplex must be added to the
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 12
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.31 (1950) nr.4 p.39
    Publication Date: 2013-03-01
    Description: The genus Podolestes, as far as at present known, is confined to the Malaysian subregion of the Indo-Australian Archipelago. Descriptions and drawings of structural details of four species are to be found in two of the writer's previous papers on Malaysian dragonf lies, viz.: New and little known Odonata of the Oriental and Australian Regions. Treubia, 15, 1935: 177-183, fig. 1-3. Descriptions and records of South-East Asiatic Odonata (II). Ibid. 17, 1940: 347-350, fig. 4-5. The species of Podolestes have been found in marshes and along muddy creeks flowing through wooded areas in low country. Owing to their retiring habits the insects are but seldom encountered and all species are rare in collections. Little or nothing is known of their life-histories, and the larva is still unknown. The six known members of the genus, two of which are here described for the first time, may be distinguished by the following Key to the species. 1. Dorsum of thorax uniform metallic bronzy black. Labrum, mandibles and genae shiny black. Ante-alar triangles bronzy-black, unmarked. Nervure Ac situated much nearer Ax2 than Ax1; nervure Ab complete, meeting Ac at the wing-margin. Quadrilateral short, markedly widened distally, costal and distal sides approximately equal in length in fore wing. Three to four postquadrangular antenodal cells. Male anal appendages of slender build, blackish in colour; superior pair a trifle longer than the inferiors; apex of inf. app. expanded, truncated and slightly notched 2. —. Dorsum of thorax with two pairs of light-coloured spots on mesepisternum, and sides with an oblique band extending from below the spiracle upwards as far as the dorsal
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 13
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.31 (1950) nr.7 p.67
    Publication Date: 2013-03-01
    Description: On trouvera ici l'étude d'une partie des Hepialidae du Musée de Leiden que le Dr. van Regteren Altena a bien voulu nous confier pour étude, ce dont le remercions vivement. Nous y avons ajouté l'étude de quatre espèces du British Museum (N.H.) et une du Museum de Paris. HÉPIALIDES DE LA NOUVELLE GUINÉE On connait quelques Hépiales décrites de Nouvelle Guinée. Elles appartiennent au magnifique genre Oenetus H.S. et au genre Oxycanus Walk, (s.l.). On trouvera ici l'étude de quelques espèces appartenant à ce dernier genre. Grace à l'amabilité de Mr. J. D. Bradley du British Museum (N.H.), que nous remercions, les quatre espèces décrites par Joicey et Talbot (1917) ont pu etre étudièes. Paraoxycanus n. gen. Ce nouveau genre, très proche du genre Oxycanus Walk, ne comprend jusqu'à présent, à notre connaissance, que quelques Hépiales néo-guinéennes classées jadis dans le genre Porina Walk. Tindale (1936) a montré que ce dernier nom était préoccupé et que, de plus, il était synonyme d'Oxycanus Walk. L'espèce type de ce genre a été fixée par Kirby (1892) comme étant australis Walk. Ayant trouvé que l'armure génitale male des espèces étudiées était différente de celle d'australis Walk. nous devons créer ce genre. On pourra comparer les figures 7 et 8. La nervation est la meme que celle du genre Oxycanus Walk. La patte prothoracique porte un strigil. Les antennes ne sont pas fortement bipectinees, mais seulement avec un petit bouquet de soies a l'apex de chaque article. Enfin dans rarmure genitale male il existe une nette difference dans le vinculum, dans les relations de celui-ci avec la membrane mtersegmentaire
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 14
    facet.materialart.
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    In:  Zoologische Verhandelingen (0024-1652) vol.11 (1950) nr.1 p.1
    Publication Date: 2013-03-01
    Description: CONTENTS Introduction............... 3 Systematic survey of the Limacidae of the central and western Canary Islands 5 Biogeographical notes on the Limacidae of the Canary Islands . . . . 21 Alphabetical list of the persons who collected or observed Limacidae in the Canary Islands.............. 31 Literature............... 32 INTRODUCTION In the spring of 1947 I was so fortunate as to join for some 9 weeks the Danish Zoological Expedition to the Canary Islands. During my stay I collected materials for the Rijksmuseum van Natuurlijke Historie at Leiden, paying special attention to the land- and freshwater Mollusca. This paper contains the first results of the examination of the Mollusca collected. My Danish friends Dr. Gunnar Thorson and Dr. Helge Volsøe generously put at my disposal the non-marine Mollusca they collected during their stay in the Canaries. When the material has been worked up, duplicates will be deposited in the Zoological Museum at Copenhagen. I am indebted to several persons who helped me in various ways in the investigations here published. Prof. Dr. N. Hj. Odhner (Stockholm) very kindly put at my disposal a MS list of all the Mollusca of the Canary Islands and their distribution, which he had compiled for private use. Mr. Hugh Watson (Cambridge) never failed to help me by examining or lending specimens, and in detailed letters gave me the benefit of his great experience. During my stay in Paris in March 1950 Dr. G. Ranson and Dr. A. Franc put at my disposal for examination the Canarian slugs present in the Muséum
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 15
    Publication Date: 2019-06-28
    Description: Numerical solutions of the differential equation obtained from the momentum theorem for the development of a turbulent boundary layer along a thermally insulated surface in two-dimensional and in radial shock-free flow are presented in tabular form for a range of Mach numbers from 0.100 to 10. The solution can be used in a step-wise procedure with any given distribution of favorable pressure gradients and for zero pressure gradients. Solutions are also given for use with moderate adverse pressure gradients. The mean velocity in the boundary layer is approximated by a power-law profile. In view of the stepwise integration methods to be used, the exponent designated the profile shape can be varied along the surface between the integral fraction limits 1/5 and 1/11 through interpolation. Agreement obtained between theoretical and experimental boundary-layer development in a supersonic nozzle at a nominal Mach number of 2 indicates the general validity of the approximations used in the analysis - in particular, the method of extrapolating low-speed skin-friction relations to high Mach number flows. The extrapolation method used assumes that the skin-friction coefficient depend primarily on Reynolds number, provided that the density and the kinematic viscosity are evaluated at surface conditions.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TN-2045
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  • 16
    Publication Date: 2019-07-11
    Description: Performance and boundary-layer data were taken in a 12 degree 10-inch inlet-diameter conical diffuser of 2:1 exit- to inlet-area ratio. These data were taken for two inlet-boundary-layer conditions. The first condition was that of a thinner inlet boundary later (boundary-layer displacement thickness, delta* approximately equal to 0.034) produced by an inlet section approximately 1 inlet diameter in length between the entrance bell and the diffuser. The second condition was a thicker inlet boundary layer (delta* approximately equal to 0.120) produced by an additional inlet section length of approximately 6 diameters. Longitudinal static-pressure distributions were measured fro wall static orifices. Transverse total- and static-pressure surveys were made at the inlet and exit stations. Boundary-layer velocity distributions were measured at seven stations between the inlet and exit. These data were obtained for a Reynolds number (based on inlet diameter) range of 1 x 10(exp 6) to 3.9 x 10(exp 6). The corresponding Mach number range was from M = 0.2 to choking. At the maximum-power-available condition supersonic flow was obtained as far as 4.5 inches downstream from the diffuser inlet with a maximum Mach number of M approximately equal to 1.5. The total-pressure loss through the diffuser in percentage of inlet dynamic pressure was approximately 2.5 percent for the thinner inlet boundary later and 5.5 percent for the thicker inlet boundary later over the lower subsonic range. These valued increased with increasing flow rate- the values for the thicker inlet boundary later more than those for the thinner inlet boundary layer. The diffuser effectiveness, expressed as the ratio of the actual static-pressure rise to the ideal static-pressure rise, was about 85 percent for the thinner inlet boundary layer and about 67 percent for the thicker inlet boundary later in the lower subsonic range. These values decrease with increasing flow rate. Separated flow was observed for both inlet-boundary-layer conditions in the region of adverse pressure gradient just downstream of the transition curvature from inlet section to diffuser. The flow for the thinner-inlet-boundary-layer condition did not fully re-establish itself along the diffuser walls. The thicker inlet-boundary-layer flow, while not completely re-establishing the normal flow pattern downstream of the separated region, did re-establish more successfully than the thinner inlet boundary layer.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-L50C02a
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  • 17
    Publication Date: 2019-07-11
    Description: The two-dimensional motion of an incompressible fluid about a closed contour with a definite velocity in magnitude and direction at infinity is considered. If, without changing the direction of the velocity at infinity, the magnitude is increased, the configuration of the streamlines remains unchanged and only the numbering of the stream function changes. There exists only one family of curves that can serve as streamlines in the incompressible flow about a given contour (at a given angle of attack); for example, the contour of an airplane wing. The case is quite different with a compressible fluid.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1252 , Izvestia Akademii Nauk, SSSR, No. 3; 153-259; Rept-3
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  • 18
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-13
    Description: The vortices forming in flowing water behind solid bodies are not represented correctly by the solution of the potential theory nor by Helmholtz's jets. Potential theory is unable to satisfy the condition that the water adheres at the wetted bodies, and its solutions of the fundamental hydrodynamic equations are at variance with the observation that the flow separates from the body at a certain point and sends forth a highly turbulent boundary layer into the free flow. Helmholtz's theory attempts to imitate the latter effect in such a way that it joins two potential flows, jet and still water, nonanalytical along a stream curve. The admissibility of this method is based on the fact that, at zero pressure, which is to prevail at the cited stream curve, the connection of the fluid, and with it the effect of adjacent parts on each other, is canceled. In reality, however, the pressure at these boundaries is definitely not zero, but can even be varied arbitrarily. Besides, Helmholtz's theory with its potential flows does not satisfy the condition of adherence nor explain the origin of the vortices, for in all of these problems, the friction must be taken into account on principle, according to the vortex theorem.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1256 , Zeitschrift fuer Mathematik und Physik; 56; 1; 1-37
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  • 19
    Publication Date: 2019-07-13
    Description: In the flow about a body with large subsonic velocity if the velocity of the approaching flow is sufficiently large, regions of local supersonic velocities are formed about the body. It is known from experiment that these regions downstream of the flow are always bounded by shock waves; a continuous transition of the supersonic velocity to the subsonic under the conditions indicated has never been observed. A similar phenomenon occurs in pipes. If at two cross sections of the pipe the velocity is subsonic and between these sections regions of local supersonic velocity are formed without completely occupying a single cross section, these regions are always bounded by shock waves.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1251 , Prikladnaya Matematika I Mekhanika; 11; 190-202
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  • 20
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    In:  CASI
    Publication Date: 2019-07-13
    Description: This document presents equations for the two-dimensional stationary problem of gas dynamics, and uses them to derive other equations, including equations for vorticity.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1260 , Prikladnaya Matematika I Mekhanica; 11; 193-198
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  • 21
    Publication Date: 2019-07-13
    Description: The use of the linearized equations of Chaplygin to calculate the subsonic flow of a gas permits solving the problem of the flow about a wing profile for absence and presence of circulation. The solution is obtained in a practical convenient form that permits finding all the required magnitudes for the gas flow (lift, lift moment velocity distribution over the profile, and critical Mach number). This solution is not expressed in simple closed form; for a certain simplifying assumption, however, the equations of Chaplygin can be reduced to equations with constant coefficients, and solutions are obtained by using only the mathematical apparatus of the theory of functions of a complex variable. The method for simplifying the equations was pointed out by Chaplygin himself. These applied similar equations to the solution of the flow problem and obtained a solution for the case of the absence of circulation.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-TM-1250 , Prikladnaya Matematika I Mekhanika; 11; 1; 105-118
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  • 22
    Publication Date: 2019-07-11
    Description: Investigations were conducted of a 12 degree 21-inch conical diffuser of 2:l area ratio to determine the interrelation of boundary layer growth and performance characteristics. surveys were made of inlet and exit from, longitudinal static pressures were recorded, and velocity profiles were obtained through an inlet Reynolds number range, determined From mass flows and based on inlet diameter of 1.45 x 10(exp 6) to 7.45 x 10(exp 6) and a Mach number range of 0.11 to approximately choking. These investigations were made to two thicknesses of inlet boundary layer. The mean value, over the entire range of inlet velocities, of the displacement thickness of the thinner inlet boundary layer was approximately 0.035 inch and that of the thicker inlet boundary layer was approximately six times this value. The loss coefficient in the case of the thinner inlet boundary layer had a value between 2 to 3 percent of the inlet impact pressure over most of the air-flow range. The loss coefficient with the thicker inlet boundary layer was of the order of twice that of the thinner inlet boundary layer at low speeds and approximately three times at high speeds. In both cases the values were substantially less than those given in the literature for fully developed pipe flow. The static-pressure rise for the thinner inlet boundary layer was of the order of 95 percent of that theoretically possible over the entire speed range. For the thicker inlet boundary layer the static pressure rise, as a percentage of that theoretically possible, ranged from 82 percent at low speeds to 68 percent at high speeds.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-L9H10
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  • 23
    Publication Date: 2019-06-27
    Description: No abstract available
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-E50I29A , REPT-2003
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  • 24
    Publication Date: 2019-06-27
    Description: No abstract available
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-E50I29A
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  • 25
    Publication Date: 2019-07-12
    Description: Tests of a 1/5 scale model of a proposed 153-foot high-speed submarine have been conducted in the Langley full-scale tunnel at the request of the Bureau of Ships, Department of the Navy. The test program included: (1) force tests to determine the drag, control effectiveness, and static stability characteristics for a number of model configurations, both in pitch and in yaw, (2) pressure measurements to determine the boundary-layer conditions and flow characteristics in the region of the propeller, and (3) an investigation of the effects of propeller operation on the model aerodynamic characteristics. In response to oral requests from the Bureau of Ships representatives t hat the basic data obtained in these tests be made available to them as rapidly as possible, this data report has been prepared to present some of the more pertinent results. All test results given in the present paper are for the propeller-removed condition and were obtained at a Reynolds number of approximately 22,300,000 based on model length.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-SL50E09a
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  • 26
    Publication Date: 2019-07-12
    Description: An investigation of the nature of the flow field behind a rectangular circular-arc wing has been conducted in the Langley 9-inch supersonic tunnel. Pitot- and static-pressure surveys covering a region of flow behind the wing have been made together with detailed pitot surveys throughout the region of the wake. In addition, the flow direction has been measured using a weathercocking vane measurements. Theoretical calculations of the variation of both downwash and sidewash with angle of attack using Lagerstrom's superposition method have been made. In addition the effect of the wing thickness on the sidewash with the wing at 0 angle of attack has been evaluated. Near an angle of attack of 0, agreement between theory and experiment is good, particularly for the downwash results, except in the plane of the wing, inboard of the tip. In this region the proximity of the shed vortex sheet and the departure of the spanwise distribution of vorticity from theory would account for the disagreement. At higher angles of attack prediction of downwash depends on a knowledge of the location of the trailing vortex sheet, in order that the downwash may be corrected for its displacement and distortion. The theoretical location of the trailing vortex sheet, based on the theoretical downwash values integrated downstream from the wing trailing edge, is shown to differ widely from the experimental case. The rolling-up of the trailing vortex sheet behind the wing tip is evidenced by both the wake surveys and the flow-angle measurements.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: NACA-RM-L50G12 , NACA Rept 1340
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