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Results 15251 - 15260 of 17,421
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Turbulence and mechanism of resistance on spheres and cylinders

Turbulence and mechanism of resistance on spheres and cylinders

Date: January 1, 1932
Creator: Ahlborn, FR
Description: The nature of turbulent flow through pipes and around obstacles is analyzed and illustrated by photographs of turbulence on screens and straighteners. It is shown that the reversal of flow and of the resistance law on spheres is not explainable by Prandtl's turbulence in the boundary layer. The investigation of the analogous phenomena on the cylinder yields a reversal of the total field of flow. The very pronounced changes in pressure distribution connected with it were affirmed by manometric measurements on spheres by Professor O. Krell. The reversal in a homogenous nonvortical flow is brought about by the advance of the stable arrangement of Karman's dead air vortices toward the test object and by the substitution of an alternatingly one-sided or rotating but stable vortex formation in place of the initially symmetrical formation. This also explains the marked variations of the models.
Contributing Partner: UNT Libraries Government Documents Department
United States Earthquakes, 1930

United States Earthquakes, 1930

Date: 1932
Creator: Neumann, Frank & Bodle, R. R.
Description: Report discussing earthquake activity in the United States during 1930. The report is broken down by regions and has sections for specific earthquakes.
Contributing Partner: UNT Libraries Government Documents Department
United States Earthquakes, 1931

United States Earthquakes, 1931

Date: 1932
Creator: Neumann, Frank
Description: Report discussing earthquake activity in the United States during 1931. The report is broken down by regions and has sections for specific earthquakes.
Contributing Partner: UNT Libraries Government Documents Department
United States Earthquakes, 1932

United States Earthquakes, 1932

Date: 1932
Creator: unknown
Description: Report discussing earthquake activity in the United States during 1932. The report is broken down by regions and has sections for specific earthquakes.
Contributing Partner: UNT Libraries Government Documents Department
Wind-tunnel tests on airfoil boundary layer control using a backward-opening slot

Wind-tunnel tests on airfoil boundary layer control using a backward-opening slot

Date: January 1, 1932
Creator: Bamber, Millard J
Description: This report presents the results of an investigation to determine the effect of boundary layer control on the lift and drag of an airfoil. Boundary layer control was accomplished by means of a backward-opening slot in the upper surface of the hollow airfoil. Air was caused to flow through this slot by a pressure which was maintained inside the airfoil by a blower. Various slot locations, slot openings, and wing pressures were used. The tests were conducted in the 5-foot atmospheric wind tunnel of the Langley Memorial Aeronautical Laboratory. Under the test conditions, the maximum lift coefficient was increased about 96 per cent for one slot arrangement, and the minimum drag coefficient was decreased about 27 per cent for another, both being compared with the results obtained with the unslotted airfoil. It is believed from this investigation that the above effects may be increased by the use of larger slot openings, better slot locations, multiple slots, improved airfoil profiles, and trailing edge flaps.
Contributing Partner: UNT Libraries Government Documents Department
Coal-Mine Fatalities in November, 1930

Coal-Mine Fatalities in November, 1930

Date: December 1931
Creator: Adams, William Waugh & Chenoweth, L.
Description: Report issued by the U.S. Bureau of Mines on the fatalities of coal miners in November, 1930. The common causes of death, and the location of the mines that the fatalities occurred in are listed. This report includes tables.
Contributing Partner: UNT Libraries Government Documents Department
Development of a non-autorotative airplane capable of steep landing

Development of a non-autorotative airplane capable of steep landing

Date: December 1, 1931
Creator: Schmidt, Wilhelm
Description: In the following we develop a non-autorotating monoplane wing. The conditions imposed on such a wing, aside from its freedom from autorotation,with respect to its polars and its construction, are taken into account as far as possible. It is indicated that the autorotation characteristics of a wing are dependent upon the speed of air flow as well as on the angle of yaw. This report postulates the knowledge of the behavior of certain conventional wings of different chords and cambers with respect to their air loads at large angles of attack.
Contributing Partner: UNT Libraries Government Documents Department
The effectiveness of a double-stem injection valve in controlling combustion in a compression-ignition engine

The effectiveness of a double-stem injection valve in controlling combustion in a compression-ignition engine

Date: December 1, 1931
Creator: Spanogle, J A & Whitney, E G
Description: An investigation was made to determine to what extent the rates of combustion in a compression-ignition engine can be controlled by varying the rates of fuel injection. The tests showed that the double-stem valve operated satisfactorily under all normal injection conditions; the rate of injection has a definite effect on the rate of combustion; the engine performance with the double-stem valve was inferior to that obtained with a single-stem valve; and the control of injection rates permitted by an injection valve of two stages of discharge is not sufficient to effect the desired rates of combustion.
Contributing Partner: UNT Libraries Government Documents Department
Factors Influencing Flow of Natural Gas Through High-Pressure Transmission Lines

Factors Influencing Flow of Natural Gas Through High-Pressure Transmission Lines

Date: December 1931
Creator: Berwald, W. B. & Johnson, T. W.
Description: Report issued by the U.S. Bureau of Mines on the effects of different operating conditions on high-pressure natural gas pipelines. Analysis of past and current studies on natural gas transmission are presented. This report includes tables, graphs, and an illustration.
Contributing Partner: UNT Libraries Government Documents Department
Goldstein's solution of the problem of the aircraft propeller with a finite number of blades

Goldstein's solution of the problem of the aircraft propeller with a finite number of blades

Date: December 1, 1931
Creator: Helmbold, H B
Description: This report examines the Betz theory on frictionless, lightly loaded propellers and Prandtl's addendum extended to moderately loaded propellers. The author then goes on to extend the discussion to Goldstein's solution for propellers with a finite number of blades.
Contributing Partner: UNT Libraries Government Documents Department