Note presenting general methods of solution for the two- and three-dimensional steady-state and two-dimensional unsteady-state equations. Four applications of the general solutions are given.

From Summary: "The flow laws of the actual flows at high Reynolds numbers differ considerably from those of the laminar flows treated in the preceding part. These actual flows show a special characteristic, denoted as turbulence. The character of a turbulent flow is most easily understood the case of the pipe flow. Consider the flow through a straight pipe of circular cross section and with a smooth wall. For laminar flow each fluid particle moves with uniform velocity along a rectilinear path."

The constant temperature bath is in operation. A ballistic type instability was detected in the calorimeter circuits and corrected by grounding the bath. Calorimeters 37, 39, 40, and 43 have been installed are now being run. Calorimeter 40 was found to be unstable, and is to be disassembled and examined for the trouble. Calorimeter 46 was finished and placed in operation. Construction details are discussed. Six Logac samples were run in Calorimeter 38. Tests of this calorimeter are in Table 1. Comparison of Calorimeter 38 in a water bath and in an ice bath is shown in Table 2. Good results were obtained for such a drastic change in environment. Calorimeter 38 was turned over to Calorimetric Assay marking the end of the tests of this particular microcalorimeter. Calorimeter 44 was completed and installed in the ice bath. Table 4 shows the results of tests. The zero bridge potential is small and is very stable compared to Calorimeter 38. The comparison of the values with those from Calorimetric Assay is summarized in Table 3. The characteristics of Calorimeter 44 are shown in Table 5. Construction details are given for the platinum-manganin bridge-type thermometer. An instrument was needed that could be …

Report presenting a comparison between the calculated design performance of a gas-turbine stator blade and its performance in a sector of an annular cascade tunnel. The gas velocities on the blade surface were computed by the stress filament method and compared with experimental values, with which they agreed satisfactorily. Results regarding discharge angle, vane-surface-velocity distribution, tangential- and axial-velocity distribution, and radial-equilibrium consideration are provided.

From Summary: "A theoretical solution is given for the critical shear stress of an infinitely long, simply supported, flat plate with identical, equally spaced, transverse stiffeners of zero torsional stiffness. Results are obtained by means of the Lagrangian multiplier method and are presented in the form of design charts. Experimental results are included and are found to be in good agreement with the theoretical results."

Report discussing the determination of the number of olefinic double bonds in less-than-milligram amounts of unsaturated fatty acid derivatives using Barcroft-Warburg tissue respirometer as a manometric microhydrogenation apparatus.

Report presenting an investigation to determine the effects of increased afterbody length on the hydrodynamic qualities of a model of a flying boat with a hull with a length-beam ratio of 15. Results regarding longitudinal stability, spray characteristics, excess thrust for take-off, landings in waves, and a summary chart are provided.

Report presenting an investigation of aircraft lubricating oil that is contaminated with various materials used in connection with airplane engines or contained in the fuel. Over 60 of the materials have been tested to determine their influence on the foaming of an aircraft lubricating oil. All but 13 of the compounds were found to have a small or negligible effect, but the other 13 were found to be strong foaming agents.

This report details events of importance reported by the Hanford Operations Office for the week ending March 30, 1949.

"Lately it has been proposed to reduce the friction drag of a body in a flow for the technically important large Reynolds numbers by the following expedient: the boundary layer, normally turbulent, is artificially kept laminar up to high Reynolds numbers by suction. The reduction in friction drag thus obtained is of the order of magnitude of 60 to 80 percent of the turbulent friction drag, since the latter, for large Reynolds numbers, is several times the laminar friction drag. In considering the idea mentioned one has first to consider whether suction is a possible means of keeping the boundary layer laminar" (p. 1).

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Report presenting the theory for calculating the free-space oscillating pressures associated with a rotating propeller at any point in space. Good agreement was found between analytical and experimental results using this method. Results regarding vibration and sound levels in the fuselage in relation to pressure level are reported.

"Methods are presented that use general correlative time-response input and output data for a linear system to determine the frequency-response function of that system. These methods give an exact description of any linear system for which such transient data are available. Examples are shown of application of a method to both an underdamped and a critically damped exact second-order system, and to an exact first-order system with and without dead time. Experimental data for a turbine-propeller engine showing the response of engine speed to change in propeller-blade angle are presented and analyzed" (p. 547).

Measurements have been made of the mean total-head and temperature fields in a round turbulent jet with various initial temperatures. The results show that the jet spreads more rapidly as its density becomes lower than that of the receiving medium, even when the difference is not sufficiently great to cause measurable deviations from the constant-density, dimensionless, dynamic-pressure profile function. Rough analytical considerations have given the same relative spread. The effective "turbulent Prandtl number" for a section of the fully developed jet was found to be equal to the true (laminar) Prandtl number within the accuracy of measurement. (author).

"In the present paper which deals with the heat transfer between the gas and the wall for large temperature drops and large velocities use is made of the method of Dorodnitsyn of the introduction of a new independent variable, with this difference, however, that the relation between the temperature field (that is, density) and the velocity field in the general case considered is not assumed given but is determined from the solution of the problem. The effect of the compressibility arising from the heat transfer is thus taken into account (at the same time as the effect of the compressibility at the large velocities). A method is given for determining the coefficients of heat transfer and the friction coefficients required in many technical problems for a curved wall in a gas flow at large Mach numbers and temperature drops" (p. 1).

Report presenting a wind-tunnel investigation at low Mach and Reynolds numbers to determine the high-lift and lateral control characteristics of a semispan wing of NACA 65(sub 2)-215 airfoil section equipped with a 25-percent-chord, full-span, slotted flap and plug and retractable ailerons. The ailerons were located at the 70-percent-chord station over the outer 49 percent of the wing semispan and were fabricated in five spanwise segments. Results regarding the wing aerodynamic characteristics, lateral control characteristics, comparison of lateral control characteristics of the plug and retractable ailerons, and a comparison of lateral control characteristics of the plug and retractable ailerons on the present wing with similar ailerons on an NACA 65-210 wing are provided.

Describes a national plan to improve poultry standards and production in the United States.

Monthly report of the U.S. Geological Survey's trace element investigations including an outline of field work, laboratory work, and staff activities that have been completed or are in process.

"Lamé's wave functions result by separation of the wave equation in elliptic coordinates and by integration of the ordinary differential equations thus originating. They are a generalization of Lamé's potential functions which originate in the same manner from the potential equation. Lamé's wave functions are applied for boundary value problems of the wave equation for regions of space bounded by surfaces of a system of confocal ellipsoids and hyperboloids" (p. 1).

Report presenting a lecture series that aims to give a survey of the more recent results of the theory of viscous fluids and their importance to actual applications. The primary focus is on the theory of the boundary of frictional layer.

Note presenting a theory of plasticity based on the concept of slip as proposed for the relationship between stress and strain for initially isotropic materials in the strain-hardening range. The theory is an extension to polyaxial stress conditions of the conventional uniaxial stress-strain relation, and time-dependent effects, such as creep and stress relaxation, are not considered.

Note presenting a study of the properties of a large forged disc of Inconel X alloy at room temperature, 1200, 1350, and 1500 degrees Fahrenheit in order to determine the level of properties obtainable in a forging of this type required for the rotor discs of gas turbines. Results regarding the hardness survey, short-term tensile properties, Charpy impact resistance, rupture test characteristics, time-deformation characteristics, creep strengths, stability characteristics, and comparison of properties of Inconel X with single and double aging treatments are provided.

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"In the present paper, the motion of a gas in a plane-parallel Laval nozzle in the neighborhood of the transition from subsonic to supersonic velocities is studied. In a recently published paper, F. I. Frankl, applying the holograph method of Chaplygin, undertook a detailed investigation of the character of the flow near the line of transition from subsonic to supersonic velocities. From the results of Tricomi's investigation on the theory of differential equations of the mixed elliptic-hyperbolic type, Frankl introduced as one of the independent variables in place of the modulus of the velocity, a certain specially chosen function of this modulus" (p. 1).