112 AIRCRAFT ENGINEERING April, 1944 Translations Issued by the N.A.C.A. of Enemy and Allied Reports ventilators , smoke ducts, air coolers, refrigeration, flat plate in a two-dimensional compressible flow Technical Memorandum No. 1050. Heat of the effect of compressibility and heating on the drying , and so forth. Transfer over the Circumference of a Heated turbulen t frictional drag coefficient in th e boundary A t present there is another application for diffu Cylinder in Transverse Flow. By Ernst laye r of an aerofoil or wing radiator . The analysis is sers in wind-tunnel design. Because of higher re Schmidt and Karl Wenner. (Warmeabgabe based on th e Prandtl-Kdrman theory of th e turbu quirement s and increased power of such installa len t boundar y layer and the Stodola-Crocco theorem tion s more attentio n must be paid to th e correctness uber den Umfang eines angeblasenen geheizten on the linear relation between the total energy of of work and the decrease in losses due to every Zylinders." Forschung auf dem Gebiete des th e How and its velocity. Formulae are obtained for section of the tunnel. Ingenieurwesens, Vol. 12, No. 2, March-April, th e velocity distribution and the frictional drag law A diffuser, being one of th e component parts of a 1941. pp. 65-73.) in a turbulent boundary layer with the compressi tunnel , can in th e event of faulty construction intro bilit y effect and heat transfer taken into account. duce considerable losses. (See reference 1.) There A method for recording the local heat-transfer I t is found tha t with increase of compressibility and fore, in the design of the new CAHI wind tunnel, coefficients on bodies in flow was developed. The temperatur e at full retardation of the flow (the i t was suggested that an experimental study of cylinder surface was kept at constant temperature temperatur e when the velocity of the flow at a diffusers be made, with a view to applying the b y th e condensation of vapour except for a narrow given point is reduced to zero in case of a n adiabatic results to wind tunnels. stri p which is heate d separately t o th e same tempera process in the gas) at a constant R , the frictional Th e experiments conducted by K. K. Baulin in tur e by electricity. The heat-transfer coefficient x dra g coefficient c decreases, both of these factors th e laboratories of CAHI upon models of diffusers a t each point was determined from the electric-heat t actin g in the same sense. (reference 2) of different cross sections, lengths, and outpu t and the temperature increase. The distri angles of divergence, were a valuable source of ex bution of the hea t transfer along the circumference perimenta l data. They were of no help, however, Technical Memorandum No. 1054. Heat of cylinders was recorded over a range of Reynolds in reaching any conclusion regarding the optimum number s of from 5000 to 426,000. The pressure Transfer and Hydraulic Flow Resistance for shape because of th e complexity an d diversity of the distribution was measured at the same time. At Streams of High Velocity. By V. L. Lclchuk. factors which all appeared simultaneously, thereby Reynolds numbers up to around 100,000 high (Jour. Tech. Phys. (U.S.S.R.), Vol. IX, No. 9, precluding th e study of the effects of any one factor maxim a of the heat transfer occurred in the pp. 808-818.) separately . forward stagnation point at 0 deg, and on th e rear On the suggestion of the director of the CAHI, side a t 180 deg., while a t around 80 deg. th e heat- Problem s of hydraulic flow resistance and heat Prof. B . N . Ureff, it was decided t o experiment on a transfe r coefficient on both sides of the cylinder transfe r for stream s wit h velocities comparabl e with two-dimensional diffuser model and determine the behind the forward stagnation point mani acoustic have present great importance for various effect of the angle of divergence. The author is fested distinct minima. Two other maxima oc fields of technical science. Especially, they have acquainte d with two experimental projects of like curred at around 115 deg. behind the forward great importance for the field of heat transfer in nature : the first was conducted with water (refer stagnatio n point between 170,000 and 426,000. designing and constructing boilers of the "Velox" ence 3), the other with air (reference 4), The first A t 426,000 the heat transfer at the location of type . In this article a description of experiments of these works, although containing a wealth of th e maxima was almost twice as great as in the an d their results as regards definition of th e laws of experimenta l data, does not indicate the nature of forward stagnation point, and the rear half of the hea t transfer in differential form for high velocity flow or its relation t o the angle of divergence. The cylinder diffused about 60 pe r cen t of th e entire heat. air streams inside smooth tubes is given. second work is limited ,to four angles—that is, Th e tests are compared with the results of other 12 deg., 24 deg., 45 deg., 90 deg. The study of this experimenta l and theoretical investigations. Technical Memorandum No. 1055. Deter diffuser did not supply any information about the mination of the Stresses Produced by the effect ot smaller angles which, because of their ad Technical Memorandum No. 1052. Deter Landing Impact in the Bulkheads of a Sea vantages , are more commonly used. The author was able t o acquaint himself with th e second work only mination of the Mass Moments and Radii of plane Bottom. By V. M. Darevsky. (Report after the experiments were started. For these Inertia of the Sections of a Tapered Wing and No. 449 of the Central Aero-Hydrodynamical reasons, as well as because on the basis of those the Centrc-of-Gravity Line along the Wing Institute, Moscow, 1939.) works no conclusion can be reached regarding the Span. By V. V. Savelyev. (Report No. 452, natur e of flow distribution, of eddies, and so forth, Th e present report deals with the determination of the Central Aero-Hydrodynamical Insti experimenta l work was continued. of the impact stresses in the bulkhead floors of a seaplane bottom. Th e dynamic problem is solved on Th e need for determining flow patterns follows tute, Moscow, 1939.) th e assumption of a certain elastic system, the floor from the fact that from them are determined Fo r computing the critical flutter velocity of a being assumed as a weightless elastic beam with method s of measurement—that is, the determina wing, among the data required arc the position of concentrate d masses a t th e ends (due t o th e mass of tion of velocities b y means of th e pitot tube, which, th e line of centres of gravity of the wing sections th e float) and with a spring which replaces the a s is well known, gives correct indications only along the span and th e mass moments and radii of elasti c action of the keel in th e centre. The distri when placed with its axis parallel to the axis of inerti a of any section of the wing about the axis bute d load on the floor is that due to the hydro- flow. passing throug h th e centre of gravit y of th e section. dynami c force acting over a certain portion of the Th e data contained in this report were obtained, A sufficiently detailed computation of these magni bottom . Th e pressure distribution over th e width of from experiments conducted by th e Aerodynamical tudes , even if the weights of all th e wing elements th e float is assumed to follow the Wagner law. The Laboratorie s of the CAHI. The solutions to some ar e known, requires a great deal of tim e expenditure. formulae given for the maximum bending moment of the mathematical problems connected with the Thu s a rapid competent worker would require from ar e derived on the assumption tha t th e keel is rela experiment s are due t o Prof. S. A. Chapligin. 70 to 100 hours for th e preceding computations for tivel y elastic, in which case it can be shown that one wing only, while hundreds of hours would be a t each instant of time the maximum bending mo require d if all th e weights were included. men t is at the point of juncture of the floor with Technical Memorandum No. 1060. Profile Wit h th e aid of th e formulae derived in th e present th e keel. The bending moment at this point is a Measurements during Cavitation. By O. paper , the work can be performed with a degree of function of the half width of the wetted surface c Walchner. ("Profilmessung bei Kavitation." accurac y sufficient for practical purposes in from one an d reaches its maximum value when c is approxi t o two hours, the only data required being' th e From a reprint of a paper presented at the Con matel y equal t o b\1 where b is th e half width of the geometric dimensions of the outer wing (tapered float. I n general , however, for computin g th e bending ference on hydromechanische Probleme des part) , the position of its longerons, th e total weight momen t the values of the bending moment at the Schiffsantriebs, Hamburg, May 18 and 19, of the outer wing, and the approximate weight of keel for certain values of c are determined and a th e longerons. I932-) curve is drawn . Th e illustrative sample computation Th e entire material presented in this paper is One of th e problems of moder n cavitation research gave for the stresses a result approximately equal applicable mainly t o wings of longeron construction is th e experimental determination of th e wing loads t o tha t obtained by the conventional factory com of th e CAHI type and investigations are, therefore, putation . on aerofoils during cavitation. Experiments made being conducted by CAHI for the derivation of on various aerofoils with the support of the naval formulae for the determination of the preceding ministr y at the Kaiser Wilhelm Institute for Flow Technical Memorandum No. 1059. An dat a for wings of other types. Research at Gottingen are described here. Experimental Investigation of the Flow of Air in a Flat Broadening Channel. By A. N. Technical Memorandum No. 1053. Turbu These Technical Memoranda are not available VedernikofT. (Report No. 137 of the Central lent "Friction in the Boundary Layer of a Flat on sale but can only be obtained by direct applica Aero-Hydrodynamical Institute, Moscow, 1926.' Plate in a Two-Dimensional Compressible tion to the Secretary, National Advisory Com Flow at High Speeds. By F. Frankl and V. Th e wide use of diffusers, in various fields of tech mittee jov Aeronautics, Washington, D.C., U.S.A. nology, ha s resulted in several experimental projects Voishel. (Report No. 321 of the Central Aero- The Editor will, however, be glad to lend his t o study their action and design. Most of the pro Hydrodynamical Institute, Moscow, 1937.) personal copy of any of them to any reader who may ject s dealt with steam (steam turbine nozzles). wish to borrow it for a few days for consultation. I n th e present report a n investigation is mad e on a Bu t diffusers have other applications—that is,
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Apr 1, 1944
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