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Two-Dimensional Potential Flows

Description: Contents include the following: Characteristic differential equations - initial and boundary conditions. Integration of the second characteristic differential equations. Direct application of Meyer's characteristic hodograph table for construction of two-dimensional potential flows. Prandtl-Busemann method. Development of the pressure variation for small deflection angles. Numerical table: relation between deflection, pressure, velocity, mach number and mach angle for isentropic changes of state according to Prandtl-Meyer for air (k = 1.405). References.
Date: November 1949
Creator: Schäefer, Manfred & Tollmien, W.
Partner: UNT Libraries Government Documents Department

A Method for Determining Cloud-Droplet Impingement on Swept Wings

Description: From Summary: "The general effect of wing sweep on cloud-droplet trajectories about swept wings of high aspect ratio moving at subsonic speeds is discussed. A method of computing droplet trajectories about yawed cylinders and swept wings is presented, and illustrative droplet trajectories are computed. A method of extending two-dimensional calculations of droplet impingement on nonswept wings to swept wings is presented."
Date: April 1953
Creator: Dorsch, Robert G. & Brun, Rinaldo J.
Partner: UNT Libraries Government Documents Department

Notes on the prediction of shock-induced boundary-layer separation

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.
Date: September 16, 1953
Creator: Lange, Roy H.
Partner: UNT Libraries Government Documents Department

Penetration of Air Jets Issuing from Circular, Square, and Elliptical Orifices Directed Perpendicularly to an Air Stream

Description: From Summary: "An experimental investigation was conducted to determine the penetration of air jets directed perpendicularly to an air stream. Jets issuing from circular, square, and elliptical orifices were investigated and the jet penetration at a position downstream of the orifice was determined- as a function of jet density, jet velocity, air-stream density, air-stream velocity, effective jet diameter, and orifice flow coeffIcient. The jet penetrations were determined for nearly constant values of air-stream density at three tunnel-air velocities arid for a large range of jet velocities and densities."
Date: February 1950
Creator: Ruggeri, Robert S.; Callaghan, Edmund E. & Bowden, Dean T.
Partner: UNT Libraries Government Documents Department

Compatibility of Metals with Liquid Fluorine at High Pressures and Flow Velocities

Description: Report presenting testing of specimens of various metals in selected geometric configurations exposed to liquid fluorine under controlled conditions of flow and pressure. None of the samples eroded, decomposed, or exhibited any measurable physical or chemical changes.
Date: April 17, 1958
Creator: Schmidt, Harold W.
Partner: UNT Libraries Government Documents Department

Unstable Capillary Waves on Surface of Separation of Two Viscous Fluids

Description: "The study of the breakup of a liquid jet moving in another medium, for example, a jet of fuel from a nozzle, shows that for sufficiently large outflow velocities the jet breaks up into a certain number of drops of different diameters. At still larger outflow velocities, the continuous part of the jet practically vanishes and the jet immediately breaks up at the nozzle into a large number of droplets of varying diameters (the case of "atomization"). The breakup mechanism in this case has a very complicated character and is quite irregular, with the droplets near the nozzle forming a divergent cone" (p. 1).
Date: April 1951
Creator: Borodin, V. A. & Dityakin, Y. F.
Partner: UNT Libraries Government Documents Department

The Characteristics Method Applied to Stationary Two-Dimensional and Rotationally Symmetrical Gas Flows

Description: "By means of characteristics theory, formulas for the numerical treatment of stationary compressible supersonic flows for the two-dimensional and rotationally symmetrical cases have been obtained from their differential equations" (p. 1).
Date: March 1949
Creator: Pfeiffer, F. & Meyer-König, W.
Partner: UNT Libraries Government Documents Department

The Condensation Line of Air and the Heats of Vaporization of Oxygen and Nitrogen

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" (p. 1).
Date: June 1953
Creator: Furukawa, George T. & McCoskey, Robert E.
Partner: UNT Libraries Government Documents Department

Elliptic Functions and Integrals with Real Modulus in Fluid Mechanics

Description: "Advantage of the elliptic functions and of the more general functions of Schwarz for fluid mechanics. Flows outside and inside polygons. Application to the calculation of an elbow diffuser for a wind tunnel. Properties of the elliptic integrals of the first kind and of the elliptic functions" (p. 1).
Date: June 1958
Creator: Legendre, Robert
Partner: UNT Libraries Government Documents Department

The Effect of Streamlining the Afterbody of an N.A.C.A. Cowling

Description: "The drag and the power cost associated with the changing of the nose of a nacelle from a streamline shape to a conventional N.A.C.A. cowling shape was investigated in the N.A.C.A. 20-foot tunnel. Full-scale propellers and nacelles were used. The increment of drag associated with the change of nose shapes was found to be critically dependent on the afterbody of the nacelle" (p. 1).
Date: December 1939
Creator: Stickle, George W.; Crigler, John L. & Naiman, Irven
Partner: UNT Libraries Government Documents Department

A Dye-Tracer Technique for Experimentally Obtaining Impingement Characteristics of Arbitrary Bodies and a Method for Determining Droplet Size Distribution

Description: "A dye-tracer technique has been developed whereby the quantity of dyed water collected on a blotter-wrapped body exposed to an air stream containing a dyed-water spray cloud can be colorimetrically determined in order to obtain local collection efficiencies, total collection efficiency, and rearward extent of impingement on the body. In addition, a method has been developed whereby the impingement characteristics obtained experimentally for a body can be related to theoretical impingement data for the same body in order to determine the droplet size distribution of the impinging cloud. Several cylinders, a ribbon, and an aspirating device to measure cloud liquid-water content were used in the studies presented herein for the purpose of evaluating the dye-tracer technique" (p. 1).
Date: March 1955
Creator: von Glahn, Uwe H.; Gelder, Thomas F. & Smyers, William H., Jr.
Partner: UNT Libraries Government Documents Department

Droplet Impingement and Ingestion by Supersonic Nose Inlet in Subsonic Tunnel Conditions

Description: "The amount of water in cloud droplet form ingested by a full-scale supersonic nose inlet with conical centerbody was measured in the NACA Lewis icing tunnel. Local and total water impingement rates on the cowl and centerbody surfaces were also obtained. All measurements were made with a dye-tracer technique" (p. 1).
Date: May 1958
Creator: Gelder, Thomas F.
Partner: UNT Libraries Government Documents Department

Comparison of Intercooler Characteristics

Description: "A method is presented of comparing the performance, weight, and general dimensional characteristics of inter-coolers. The performance and dimensional characteristics covered in the comparisons are cooling effectiveness, pressure drops and weight flows of the charge and cooling air, power losses, volume, frontal area, and width. A method of presenting intercooler data is described in which two types of charts are plotted; (1) A performance chart setting forth all the important characteristics of a given intercooler and (2) a replot of these characteristics for a number of intercoolers intended to assist in making a selection to satisfy a given set of installation conditions" (p. 1).
Date: May 1941
Creator: Reuter, J. George & Valerino, Michael F.
Partner: UNT Libraries Government Documents Department

Contribution to the Problem of Flow at High Speed

Description: Report divided into two sections about flow problems encountered at high speeds. The topics include: 1) A Few General Remarks Covering the Prandtl-Busemann Method; and 2) Effect of Compressibility in Axially Symmetrical Flow around an Ellipsoid.
Date: June 1949
Creator: Schmieden, C. & Kawalki, K. H.
Partner: UNT Libraries Government Documents Department

A Method for Rapid Determination of the Icing Limit of a Body in Terms of the Stream Conditions

Description: "The effects of existing frictional heating were analyzed to determine the conditions under which ice formations on aircraft surfaces can be prevented. A method is presented for rapidly determining by means of charts the combination of-Mach number, altitude, and stream temperature which will maintain an ice-free surface in an icing cloud. The method can be applied to both subsonic and supersonic flow. The charts presented are for Mach numbers up to 1.8 and pressure altitudes from sea level to 45,000 feet" (p. 1).
Date: March 1953
Creator: Callaghan, Edmund E. & Serafini, John S.
Partner: UNT Libraries Government Documents Department

General Correlation of Temperature Profiles Downstream of a Heated Air Jet Directed at Various Angles to Air Stream

Description: An experimental investigation was conducted to determine the temperature profiles downstream of heated air jets directed at angles of 90 deg, 60 deg, 45 deg, and 30 deg to an air stream. The profiles were determined at two positions downstream of the jet as a function of jet diameter, jet density, jet velocity, free-stream density, free-stream velocity, jet total temperature, orifice flow coefficient, and jet angle. A method is presented which yields a good approximation of the temperature profile in terms of the flow and geometric conditions.
Date: December 1952
Creator: Ruggeri, Robert S.
Partner: UNT Libraries Government Documents Department

Preliminary Tests in the NACA Tank to Investigate the Fundamental Characteristics of Hydrofoils

Description: Report discusses an investigation into the hydrodynamic properties and general behavior of simple hydrofoils. The experimental results are presented as curves of the lift and drag coefficients plotted against speed for angles of attack and depths. Properly designed hydrofoil sections were determined to have excellent characteristics and a significant reduction in the speed of cavitation.
Date: September 1940
Creator: Ward, Kenneth E. & Land, Norman S.
Partner: UNT Libraries Government Documents Department

Vibration survey of blades in 19XB axial-flow compressor: 3 - preliminary engine investigation

Description: Strain gages were used to measure blade vibrations possibly causing failure in the 10-stage compressor of the 19XB jet-propulsion engine. The seventh and tenth stages were of great concern as a result of failures experienced by the manufacturer. Strain-gage records were obtained from all stages during acceleration, deceleration, and constant speed runs. Curves are presented herein showing the maximum allowable vibratory stress for a given speed, the change of the damping coefficient with the mounting of a strain gage at the base of the blade, the effect of rotor speed, on blade natural frequency, and the effect of the order of first bending-mode vibration on stress. It was found that for all stages the lower the order of vibration the higher the stress but no destructive vibrations were detected.
Date: January 28, 1948
Creator: Meyer, André J., Jr. & Calvert, Howard F.
Partner: UNT Libraries Government Documents Department

Boundary-Layer-Transition and Heat-Transfer Measurements from Flight Tests of Blunt and Sharp 50 Degree Cones at Mach Numbers from 1.7 to 4.7

Description: Boundary-layer-transition and heat-transfer measurements were obtained from flight tests of blunt and sharp cones having apex angles of 50 deg. The test Mach number range was from 1.7 to 4.7, corresponding to free-stream Reynolds numbers, based on cone base diameter, of 18. 3 x 10(exp 6) and 32.1 x 10(exp 6), respectively. Transition on both models occurred at a local Reynolds number of 1 x 10(exp 6) to 2 X 10(exp 6) based on distance from the stagnation point. Transition Reynolds numbers based on momentum thickness were between 320 and 380 for the blunt cone. The model surface roughness was 25 rms microinches or greater. Turbulent heat transfer to the conical surface of the blunt cone at a Mach number of 4 was 30 percent less than that to the surface of the sharp cone. Available theories predicted heat-transfer coefficients reasonably well for the fully laminar or turbulent flow conditions.
Date: April 18, 1957
Creator: Chauvin, Leo T. & Speegle, Katherine C.
Partner: UNT Libraries Government Documents Department

Investigation of Flow Conditions and the Nature of the Wall-Constriction Effect Near and at Choking by Means of the Hydraulic Analogy

Description: Report presenting an investigation of the closed wind-tunnel phenomenon of choking and the wall-constriction effects in the subsonic Mach number range where supersonic Mach numbers appear using the hydraulic analogy. Application of the results to wind tunnel testing, the subsonic choking phenomena, and effects of the walls are described.
Date: September 1, 1948
Creator: Matthews, Clarence W. & Wright, Ray H.
Partner: UNT Libraries Government Documents Department

Analytical Treatment of Normal Condensation Shock

Description: "The condensation of water vapor in an air has the following consequences: acquisition of heat (liberated heat vaporization; loss of mass on the part of the flowing gas (water vapor is converted to liquid); change in the specific gas constants and of the ratio k of the specific heats (caused by change of gas composition). A discontinuous change of state is therefore connected with the condensation; schlieren photographs of supersonic flows in two-dimensional Laval nozzles show two intersecting oblique shock fronts that in the case of high humidities may merge near the point of intersection into one normal shock front" (p. 1).
Date: July 1947
Creator: Heybey
Partner: UNT Libraries Government Documents Department

Calculation of Turbulent Expansion Processes

Description: "On the basis of certain formulas recently established by L. Prandtl for the turbulent interchange of momentum in stationary flows, various cases of "free turbulence" - that is, of flows without boundary walls - are treated in the present report. Prandtl puts the apparent shearing stress introduced by the turbulent momentum interchange. This present report deals first with the mixing of an air stream of uniform velocity with the adjacent still air, than with the expansion or diffusion of an air jet in the surrounding air space" (p. 1).
Date: September 1945
Creator: Tollmien, Walter
Partner: UNT Libraries Government Documents Department

The Boundary Layers in Fluids with Little Friction

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" (p. 1).
Date: February 1950
Creator: Blasius, H.
Partner: UNT Libraries Government Documents Department