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  Partner: UNT Libraries Government Documents Department
 Collection: National Advisory Committee for Aeronautics Collection
Investigation of Flow in a Centrifugal Pump

Investigation of Flow in a Centrifugal Pump

Date: July 1, 1946
Creator: Fischer, Karl
Description: The investigation of the flow in a centrifugal pump indicated that the flow patterns in frictional fluid are fundamentally different from those in frictionless fluid. In particular, the dead air space adhering to the section side undoubtedly causes a reduction of the theoretically possible delivery head. The velocity distribution over a parallel circle is also subjected to a noticeable change as a result of the incomplete filling of the passages. The relative velocity on the pressure side of the vane, which for passages completely filled with active flow would differ little from zero even at comparatively lower than normal delivery volume, is increased, so that no rapid reverse flow occurs on the pressure side of the vane even for smaller delivery volume. It was established, further, that the flow ceases to be stationary for very small quantities of water. The inflow to the impeller can be regarded as radial for the operating range an question. The velocity triangles at the exit are subjected to a significant alteration in shape ae a result of the increased peripheral velocity, which may be of particular importance in the determination of the guide vane entrance angle.
Contributing Partner: UNT Libraries Government Documents Department
The Flow Through Axial Turbine Stages of Large Radial Blade Length

The Flow Through Axial Turbine Stages of Large Radial Blade Length

Date: April 1, 1947
Creator: Eckert & Korbacher
Description: A calulation of the flow in turbine blading is reported that includes the calculation of effect of centrifugal force. Frictional losses on the stator blades and rotor blades are allowed.
Contributing Partner: UNT Libraries Government Documents Department
On Possible Similarity Solutions for Three-Dimensional Incompressible Laminar Boundary-Layer Flows Over Developable Surfaces and with Proportional Mainstream Velocity Components

On Possible Similarity Solutions for Three-Dimensional Incompressible Laminar Boundary-Layer Flows Over Developable Surfaces and with Proportional Mainstream Velocity Components

Date: September 1, 1958
Creator: Hansen, Arthur G.
Description: Analysis is presented on the possible similarity solutions of the three-dimensional, laminar, incompressible, boundary-layer equations referred to orthogonal, curvilinear coordinate systems. Requirements of the existence of similarity solutions are obtained for the following: flow over developable surface and flow over non-developable surfaces with proportional mainstream velocity components.
Contributing Partner: UNT Libraries Government Documents Department
On the Contribution of Turbulent Boundary Layers to the Noise Inside a Fuselage

On the Contribution of Turbulent Boundary Layers to the Noise Inside a Fuselage

Date: December 1, 1956
Creator: Corcos, G. M. & Liepmann, H. W.
Description: The following report deals in preliminary fashion with the transmission through a fuselage of random noise generated on the fuselage skin by a turbulent boundary layer. The concept of attenuation is abandoned and instead the problem is formulated as a sequence of two linear couplings: the turbulent boundary layer fluctuations excite the fuselage skin in lateral vibrations and the skin vibrations induce sound inside the fuselage. The techniques used are those required to determine the response of linear systems to random forcing functions of several variables. A certain degree of idealization has been resorted to. Thus the boundary layer is assumed locally homogeneous, the fuselage skin is assumed flat, unlined and free from axial loads and the 'cabin' air is bounded only by the vibrating plate so that only outgoing waves are considered. Some of the details of the statistical description have been simplified in order to reveal the basic features of the problem. The results, strictly applicable only to the limiting case of thin boundary layers, show that the sound pressure intensity is proportional to the square of the free stream density, the square of cabin air density and inversely proportional to the first power of the damping constant ...
Contributing Partner: UNT Libraries Government Documents Department
Application of the Method of Coordinate Perturbation to Unsteady Duct Flow

Application of the Method of Coordinate Perturbation to Unsteady Duct Flow

Date: September 1, 1958
Creator: Himmel, Seymour C.
Description: The method of coordinate perturbation is applied to the unsteady flow of a compressible fluid in ducts of variable cross section. Solutions, in the form of perturbation series, are obtained for unsteady flows in ducts for which the logarithmic derivative of area variation with respect to the space coordinate is a function of the 'smallness' parameter of the perturbation series. This technique is applied to the problem of the interaction of a disturbance and a shock wave in a diffuser flow. It is found that, for a special choice of the function describing the disturbance, the path of the shock wave can be expressed in closed form to first order. The method is then applied to the determination of the flow field behind a shock wave moving on a prescribed path in the x,t-plane. Perturbation series solutions for quite general paths are developed. The perturbation series solutions are compared with the more exact solutions obtained by the application of the method of characteristics. The approximate solutions are shown to be in reasonably accurate agreement with the solutions obtained by the method of characteristics.
Contributing Partner: UNT Libraries Government Documents Department
Gas-Dynamic Investigations of the Pulse-Jet Tube, Parts 1 and 2

Gas-Dynamic Investigations of the Pulse-Jet Tube, Parts 1 and 2

Date: February 1, 1947
Creator: Shultz-Grunow, F.
Description: Based upon a simplified representation of the mode of operation of the pulse-jet tube, the effect of the influences mentioned in the title were investigated and it will be shown that, for a jet tube with a fccmndesigned to be aerodynamically favorable, the ability to operate is at least questionable. By taking into account the course of the development of pressure by combustion, a new insight has been obtained into the processes of motion within the jet tube, an insight that explains a number of empirical observations, namely: certain particulars of the sequence of pressure variations; the existence of an optimum valve-opening ratio; the occurrence of an intrusion of air; and the existence of a flight speed above lrhichthe jet tube ceases to operate. At too great an opening ratio or at too great a flight s-peed, the continuous flow through the tube is too predominant over the oscilla~ory process to perinitthe occurrence of an explosion powerful enough to maintain continuous operation. Certain possible means of making the operation of the jet tube more independent of the flight speed and of reducing the flow losses were proposed and discussed.
Contributing Partner: UNT Libraries Government Documents Department
Some Basic Laws of Isotropic Turbulent Flow

Some Basic Laws of Isotropic Turbulent Flow

Date: September 1, 1945
Creator: Loitsianskii, L. G.
Description: An Investigation is made of the diffusion of artificially produced turbulence behind screens or other turbulence producers. The method is based on the author's concept of disturbance moment as a certain theoretically well-founded measure of turbulent disturbances.
Contributing Partner: UNT Libraries Government Documents Department
Theory of Wings in Nonstationary Flow

Theory of Wings in Nonstationary Flow

Date: June 1, 1947
Creator: Nekrasov, A. I.
Description: This paper gives an overview of equations for vibration and flutter affecting airplane wings in nonstationary flow.
Contributing Partner: UNT Libraries Government Documents Department
Possibilities of Reducing the Length of Axial Superchargers for Aircraft Motors

Possibilities of Reducing the Length of Axial Superchargers for Aircraft Motors

Date: January 1, 1947
Creator: Eckert, B.
Description: Axial blowers are gaining importance as aircraft engine superchargers. However, the pressure head obtainable per stage is small. Due to the necessary great number of stages, the physical length of the blower becomes too great for an airworthy device. This report discusses several types of construction that permit a reduction in the length of the blower.
Contributing Partner: UNT Libraries Government Documents Department
Dornier "Superwal" commercial seaplane with : two Rolls-Royce "Condor" 600 HP. engines

Dornier "Superwal" commercial seaplane with : two Rolls-Royce "Condor" 600 HP. engines

Date: February 1, 1927
Creator: unknown
Description: In November 1926, an exhibition flight of the Dornier giant flying boat was made for 3/4 of an hour. It was a larger version of the Dornier Wal, with a stepped hull, and wing stubs for lateral stability. It has a range of 1200 miles and is outfitted for baggage and 8 passengers.
Contributing Partner: UNT Libraries Government Documents Department