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Hydrodynamic Characteristics of Missiles Launched Under Water

Description: Report presenting some of the hydrodynamic problems associated with launching an air missile from underwater. The results of an experiment with models are also provided, including deviation angle, effect of forward speed of the submarine, curved path of the missile, and potential environmental disruptions.
Date: June 27, 1958
Creator: Dawson, John R.
Partner: UNT Libraries Government Documents Department

Propagation of Density Disturbances in Air-Water Flow

Description: From Introduction: "In this work, a forced-circulation air-water loop was employed for investigating the behavior of void perturbations. Upon attaining steady-state conditions, disturbances in the void fraction were superimposed at very low frequencies (~0.4 cps). A better understanding of hydrodynamic transient behavior will generate more confidence in the design of boiling-water reactor systems."
Date: June 1965
Creator: Nassos, George P.
Partner: UNT Libraries Government Documents Department

Experimental investigation of the flow field behind an aspect-ratio-10 hydrofoil near the water surface

Description: Report presenting an investigation of the flow field behind a hydrofoil with an 8-inch chord and an aspect ratio of 10; the foil was operating at about 0.75 chord below the free-water surface. The downwash and water surface profiles were measured behind the hydrofoil for a variety of positions of interest. Results regarding surface contours, a comparison of surface profiles with theoretical two-dimensional waves, and downwash are presented.
Date: February 24, 1953
Creator: Carter, Arthur W. & Butler, Roger V.
Partner: UNT Libraries Government Documents Department

Variation of hydrodynamic impact loads with flight-path angle for a prismatic float at 0 and -3 degree trim and with a 22 1/2 degree angle of dead rise

Description: Report presenting testing on a prismatic float model to determine the relationship between the vertical landing acceleration and flight-path angle for seaplanes landing in smooth water. Results regarding the maximum load factor, maximum impact normal acceleration, pressures, and stability of landings are provided.
Date: April 1947
Creator: Batterson, Sidney A.
Partner: UNT Libraries Government Documents Department

Preliminary tank investigation of the use of single monoplane hydrofoils for high-speed airplanes

Description: Report presenting an investigation of the hydrodynamic take-off and landing characteristics of a model of a hypothetical jet- and rocket-propelled high-speed airplane fitted with various designs of a single monoplane hydrofoil mounted near the center of gravity. This testing is performed to determine the feasibility of the water-based operation of high-speed airplanes. Results regarding the general hydrodynamic characteristics, development of hydrofoils, and effects of some hydrofoil parameters are provided.
Date: March 22, 1949
Creator: King, Douglas A. & Rockett, John A.
Partner: UNT Libraries Government Documents Department

Planing characteristics of three surfaces representative of hydro-ski forms

Description: Report presenting the planing characteristics, as determined by tank tests, of three surfaces representative of hydro-ski forms. One surface had a rectangular plan form with a flat bottom, one had a rectangular plan form with a transversely curved bottom, and the third had a flat bottom and triangular plan form. Results are provided in the form of plots of the load on the water, resistance, trimming moment, and draft against total wetted area with speed and trim as parameters.
Date: March 29, 1949
Creator: Wadlin, Kenneth L. & McGehee, John R.
Partner: UNT Libraries Government Documents Department

Determination of rate, area, and distribution of impingement of waterdrops on various airfoils from trajectories obtained on the differential analyzer

Description: From Summary: "The trajectories of waterdrops in air flowing over airfoils are determined for three airfoil - angle-of-attack combinations using the differential analyzer to solve the differential equations of motion of the waterdrops. From these trajectories the rate of water impingement, the area of impingement, and the distribution of impingement are determined as functions of two dimensionless moduli. Comparisons are made of the rate of water impingement on these airfoils and the rate of water impingement on cylinders."
Date: February 16, 1949
Creator: Guibert, A. G.; Janssen, E. & Robbins, W. M.
Partner: UNT Libraries Government Documents Department

Vortices and the related principles of hydrodynamics

Description: Here, conceptions concerning vortices are illustrated by the simplest possible examples. Mathematical formulas and similar means of presentation, which, for the most part, do not help the understanding of persons not versed therein, have been avoided as much as possible. Instead, the author has endeavored to demonstrate the phenomena by means of simple geometrical and mechanical illustrations. For the sake of clarity, the author chiefly considers currents in one plane only, a situation that can be readily represented by diagrams. Some of the peculiarities of vortices in three dimensional flow are briefly discussed.
Date: November 1921
Creator: Betz, A.
Partner: UNT Libraries Government Documents Department

Hydrodynamic and aerodynamic tests of four models of outboard floats: (N.A.C.A. models 51-A, 51-B, 51-C, and 51-D)

Description: Four models of outboard floats (N.A.C.A. models 51-A, 51-B, 51-C, and 51-D) were tested in the N.A.C.A. tank to determine their hydrodynamic characteristics and in the 20-foot wind tunnel to determine their aerodynamic drag. The results of the tests, together with comparisons of them, are presented in the form of charts. From the comparisons, the order of merit of the models is estimated for each factor considered. The best compromise between the various factors seems to be given by model 51-D. This model is the only one in the series with a transverse step.
Date: December 1938
Creator: Dawson, John R. & Hartman, Edwin P.
Partner: UNT Libraries Government Documents Department

A theoretical and experimental investigation of the lift and drag characteristics of hydrofoils at subcritical and supercritical speeds

Description: From Summary: "A theoretical and experimental investigation at subcavitation speeds was made of the effect of the free-water surface and rigid boundaries on the lift and drag of an aspect-ratio-10 hydrofoil at both subcritical and supercritical speeds and of an aspect ratio-4 hydrofoil at supercritical speeds. Approximate theoretical solutions for the effects of the free-water surface and rigid boundaries on drag at subcritical speeds are developed. An approximate theoretical solution for the effects of these boundaries on drag at subcritical speeds is also presented. The agreement between theory and experiment at both supercritical and subcritical speeds is satisfactory for engineering calculations of hydrofoil characteristics from aerodynamic data. The experimental investigation indicated no appreciable effect of the limiting speed of wave propagation on lift-curve slope or angle of zero lift. It also showed that the increase in drag as the critical speed is approached from the supercritical range is gradual. The result is contrary to the abrupt increase at the critical speed predicted by theory."
Date: 1955
Creator: Wadlin, Kenneth L.; Shuford, Charles L., Jr. & McGehee, John R.
Partner: UNT Libraries Government Documents Department

Aerodynamic and hydrodynamic tests of a family of models of flying-boat hulls derived from a streamline body: NACA model 84 series

Description: Report presenting a series of related flying-boat hull forms with various combinations of aerodynamic and hydrodynamic requirements that were tested in an NACA tank and high-speed tunnel. Effects explored included varying the height of the bow, varying the height of the stern, increasing the angle of dead rise at the bow, decreasing the angle of dead rise on the afterbody, increasing the depth of step, increasing the angle of afterbody keel, adding chine flare, adding a third planing surface, and rounded chines at the bow.
Date: September 1943
Creator: Parkinson, John B.; Olson, Roland E.; Draley, Eugene C. & Luoma, Arvo A.
Partner: UNT Libraries Government Documents Department

Applications of Modern Hydrodynamics to Aeronautics

Description: The report gives, rather briefly, in part one an introduction to hydrodynamics which is designed to give those who have not yet been actively concerned with this science such a grasp of the theoretical underlying principles that they can follow the subsequent developments. In part two there follows a separate discussion of the different questions to be considered, in which the theory of aerofoils claims the greatest portion of the space. The last part is devoted to the application of the aerofoil theory to screw propellers. A table giving the most important quantities is at the end of the report. A short reference list of the literature on the subject and also a table of contents are added.
Date: 1923
Creator: Prandtl, L.
Partner: UNT Libraries Government Documents Department

Note on the calculation of boundary layers

Description: The properties of the solutions of the hydrodynamic equations of viscous fluid by "boundary-layer omission" are discussed. A method is indicated for the numerical determination of the solution for a known initial profile u(x(sub o),y) and pressure distribution p(x) within the region.
Date: November 1940
Creator: Prandtl, L.
Partner: UNT Libraries Government Documents Department

Hydrodynamic characteristics of a model of a proposed six-engine hull-type seaplane designed for supersonic flight

Description: Report presenting an investigation of the hydrodynamic characteristics of a six-engine hull-type seaplane designed for supersonic flight. Four engines were mounted on top of the wing in individual nacelles and two engines were mounted on the top of the aft section of the hull. Results regarding the acceleration, gross-load-total-resistance ratio, stabilizer deflections, and reaction of the inlets to water are presented.
Date: July 14, 1958
Creator: Coffee, Claude W., Jr.
Partner: UNT Libraries Government Documents Department

Effects of nose shape and spray control strips on emergence and planing spray of hydro-ski models

Description: Report presenting the emergence- and planing-spray characteristics of flat-bottom surfaces representing hydro-skis with various bow shapes and deflectors. The most favorable emergence spray was obtained with a bow of triangular plan form and sharp profile. Results regarding practical design considerations are also provided.
Date: July 1958
Creator: McGehee, John R.
Partner: UNT Libraries Government Documents Department

Hydrodynamic characteristics of aerodynamically refined planing-tail hulls

Description: Report presenting an investigation to determine the hydrodynamic characteristics of two aerodynamically refined planing-tail hulls. One hull had an afterbody shaped like a tapered boom and the other had two afterbodies with tapered booms fairing out of engine nacelles. Results regarding take-off stability and trim, landing stability, spray, resistance, directional stability, and static transverse stability are presented.
Date: March 28, 1949
Creator: McKann, Robert & Coffee, Claude W.
Partner: UNT Libraries Government Documents Department

Planing characteristics of six surfaces representative of hydro-ski forms

Description: Report presenting the planing characteristics for six surfaces representative of hydro-ski forms as determined by tank tests.Testing was made at specified trims, speeds, and sufficient loads to define variations with wetted length. Data from the testing is provided in the form of plots of wetted length, load, resistance, trimming moment, and draft against wetted area.
Date: February 10, 1950
Creator: Wadlin, Kenneth L. & McGehee, John R.
Partner: UNT Libraries Government Documents Department

Water landing investigation of a model having a heavy beam loading and a 30 degree angle of dead rise

Description: Results presenting testing of a model with heavy beam loading and an angle of dead rise of 30 degrees subjected to smooth-water impacts in the Langley impact basin. Testing was made at fixed trims of 6 degrees, 15 degrees, 30 degrees, and 45 degrees for a range of flight-path angles and consistent beam-loading coefficient. Time histories of horizontal and vertical displacements, vertical velocity, vertical acceleration, and pitching moment are provided.
Date: February 1950
Creator: Batterson, Sidney A. & McArver, A. Ethelda
Partner: UNT Libraries Government Documents Department

Preliminary tank tests of NACA hydro-skis for high-speed airplanes

Description: Report presenting the results from tank landing and take-off tests with a dynamic model of a hypothetical jet-propelled airplane equipped with NACA hydro-skis. Results regarding landing tests, take-off tests, and practical considerations for the creation of hydro-ski configurations are provided. The hydro-skis suitable for flush retraction into streamline fuselages do appear to offer a practical means of water take-offs and landings.
Date: November 26, 1947
Creator: Dawson, John R. & Wadlin, Kenneth L.
Partner: UNT Libraries Government Documents Department

Hydrodynamic characteristics of a swept planing-tail hull

Description: Report presenting the hydrodynamic characteristics of a swept planing-tail hull as determined by water tank testing. The hull shape was based on results from previous testing indicating that symmetrical airfoil sections and slender boom-like afterbodies lower the drag. Results regarding spray characteristics, take-off stability and trims, landing stability, resistance, and directional stability are presented.
Date: September 12, 1949
Creator: Mckann, Robert E.; Coffee, Claude W. & Arabian, Donald D.
Partner: UNT Libraries Government Documents Department