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© 2004 Elsevier B.V. Financial support from Ministerio de Ciencia y Tecnología of Spain under Project BFM2000-0625 is gratefully acknowledged., Electroosmosis experiments through a Nafion membrane have been performed using methanol–water KCl solutions in different experimental situations. The influence on the electroosmotic transport of the percentage of methanol on solvent at different electrolyte concentrations has been studied. The experimental results show that the presence of methanol on the solutions affects strongly to the electroosmotic flow. From the current–voltage curves determined for this membrane system, the limiting currents were obtained at different volume percentages of methanol. The values obtained decrease with increasing the percentage of methanol and a minimum value seems to be reached at certain percentage of alcohol., Ministerio de Ciencia y Tecnología of Spain, Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

The dynamics of laser-ablated carbon plume propagation through different background Nitrogen pressure have been investigated with time and space-resolved emission spectroscopy. Results of temporal and spatial evolution of CI and CII emissions lines at 4267A and 2478A 4267A respectively under different nitrogen pressure show that there are two stages of expansion in accordance with shock wave and drag force model propagation model, Pub. in International Conference on Phenomena in Ionized Gases (26th), v4 p199-200, July 2003. This article is from ADA421147 International Conference on Phenomena in Ionized Gases (26th) Held in Greifswald, Germany on 15-20 July 2003. Proceedings, Volume 4

Report developed under SBIR contract for topic AF99-2O5. There is a need for an innovative Graphical User Interface (GUI), or Visual Modeling Environment, for the Turbine Engine Reverse Modeling Aid Program (TERMAP) which is used by DoD, NASA, and contractors for modeling gas turbine engine propulsion systems. The development of such a user-friendly, innovative GUI was undertaken during this Phase I by SRS Technologies. This Phase I SBIR contract has resulted:%in a user-friendly, Windows- based GUI which meets and exceeds the performance objectives. This report summarizes the Phase I results and software capabilities. Visual TERMAP can import existing TERMAP input files or create new engine cycle configurations using the drag and drop interface. Visual TERMAP automatically tracks station numbers and TERMAPTs Parameter Index Codes (PICs). Compressor and turbine maps can be scaled and plotted. Visual TERMAP also performs trade studies and graphs results using an integrated graphing program. Software deliverables include the Visual TERMAP software program.

The technical note (TN) "Resistance Due to Vegetation" (Ecosystem Management and Restoration Research Program (EMRRP) TN SR-7) presents equations for the evaluation of Manning's resistance coefficient in floodways occupied by vegetation. These equations require an estimate of the drag coefficient and area for the vegetation. This technical note presents a means to make these estimates.

The report describes a falling-sphere system which was designed to determine air density at altitudes from 40 km to at least 140 km above the earth's surface. The principal sensor for the system is a triaxial accelerometer which is contained in a 10-inch sphere. The system enables measurements of the drag acceleration experienced by the sphere as it falls through the earth's atmosphere. The accelerometer has a spherical cavity which in turn contains a spherical reference mass. Drag acceleration causes the reference mass to be displaced within the cavity. Capacitive sensors, mounted in the walls of the cavity, monitor the position of the reference mass. Displacement is monitored along three axes. The axial components of displacement are converted to calibrated voltages which are transmitted to recording stations on the ground. Drag acceleration is calculated from displacement-time data. The operation of the system is described, and details of the accelerometer, the associated electronic circuitry, and the physical structure are presented. Calibration and test procedures are also discussed. (Author)

The present report describes program CABUOY, which analyzes in some detail the two-dimensional dynamic behavior of general ocean cable systems consisting of a surface buoy, connecting cable, and intermediate bodies. The report briefly presents the calculations which are carried out in the program, gives computer time requirements for several cable cases, and outlines some relatively small additional areas of work. Detailed imput instructions are given in the Appendix.

Hydraulic ram is the phenomenon associated with the damage caused by high speed projectile impacts with fuel tanks. It is divided into five phases, entry, shock, drag, cavity and exit. The entry, shock and drag phases were of concern in this study. An analytical solution for the pressures developed in the shock phase was formulated based on bullet impact parameters. Pressures developed in the drag phase were experimentally correlated with theoretical predictions. These pressures were proven to be dependent on front wall wave reflections.

This report develops a technique to represent the supersonic portion of a ballistic projectile's trajectory in analytic form. Particular emphasis is placed on the first two seconds of the trajectory as this region is of most importance in air-to-air combat applications where accurate computation of the projectile's position is required. Equations of motion are developed by treating the projectile as a translating mass particle in a plane parallel to the direction of gravity. Drag is the dominant forcing term in the direction opposite to the initial motion and gravity is dominant normal to the initial motion. Ignoring further perturbative effects of gravity and air density, these equations are solved in closed form.

A detailed description is given of Program CAB3E, a general FORTRAN 4 program for predicting the three-dimensional, steady-state configuration of extensible flexible cable systems. The cable system may consist of an arbitrary number of different cable segments and intermediate bodies. All but the initial body are restricted to simple bodies having only weight and drag forces. The description includes the equations of equilibrium for the cable and intermediate bodies, the subroutines of the program, and instructions for program usage. Several sample problems are included.

Observations of artifical earth satellites provide a means of establishing an origin, orientation, scale and control points for a coordinate system. Neither existing data nor future data are likely to provide significant information on the .001'' angle provided data to about .01'' accuracy on the pole position and to possibly a meter on the origin of the system and for control points. The longitude origin is essentially arbitrary. While these accuracies permit acquisition of useful data on tides and polar motion through dynamic analyses, they are inadequate for determination of crustal motion or significant improvement in polar motion. The limitations arise from gravity, drag and radiation forces on the satellites as well as from instrument errors. Improvements in laser equipment and the launch of the dense LAGEOS satellite in an orbit high enough to suppress significant gravity and drag errors will permit determination of crustal motion and more accurate, higher frequency, polar motion. (Modified author abstract)

The document describes the design, construction and operating performance of a high speed (0.8 Mach) open circuit induction type wind tunnel. The tunnel was developed primarily to test ram air submerged scoops used in heat exchange cooling systems. A tunnel wall simulates the airplane surface for this type of test. An instrumentation system was developed to record pressures for evaluating boundary layer parameters, ram air system wake drag and internal performance. (Author)

This report presents the results of bare hull resistance tests on one model which represents a candidate hull form for a proposed U. S. Coast Guard medium polar icebreaker. This model has the same form forward of station 7. The tests were oriented toward choice of an optimum afterbody shape. (Author)

The primary objective of this program was to define a function between the striking velocity for 60-grain and 240-grain and 240-grain random shaped bomb fragments and their depth into the wallboard trade named Nu-Wood. The 60-grain fragments were fired from a 20mm Mann barrel and the 240-grain fragments from a 30mm Mann barrel into bundled Nu-Wood. The striking velocities for the 60-grain fragments were in the 600 ft/sec to 5000 ft/sec range and the 240-grain fragments in the 300 ft/sec to 3500 ft/sec range. The graph of fragment striking velocity as a function of depth into Nu-Wood showed a wide range of depths for approximately 2000 ft/sec. A least squares curve would not be valuable since the penetration spread is too wide at given velocities. Fragment penetration into Nu-Wood from firing cylinders does not give a realistic picture of 60-grain and 240-grain actual bomb fragmentation spread. The depth of penetration is not a primary function of the initial presented areas of impacting 240-grain fragments for 500 ft/sec to 3000 ft/sec velocities. When a factor of two or more exists between impacting presented areas for 60- grain bomb fragments, then the presented area seems to influence penetration.

The two-dimensional free-surface flow generated by a singularity moving with near-critical speed (i.e. with Froude number referred to the water depth near unity) is solved by using the method of matched asymptotic expansions. In the vicinity of the singularity the problem is solved by an infinitesimal wave expansion (inner expansion) while at large distances from the singularity shallow water theory provides the proper solution (outer expansion). A composite expansion provides a uniformly-valid solution for the velocity components, the free-surface profile and the drag force. These two basic approaches of water-wave theory are shown to be solutions of the same flow problem, but valid in different regions. Although the inner expansion satisfies linear equations, the solution depends nonlinearly on the small parameter of the problem (the singularity strength).

Values of residuary resistance from model tests were previously presented for a methodical series of slender displacement hull forms which had been tested up to high speeds. The report gives values of total resistance for the hull forms of the series so that their relative merits can readily be seen. The values of total resistance were calculated for boats of 200-ton displacement to facilitate comparison with resistance data for U. S. Navy hydrofoil boats. The form of the data presentation is such as to provide guidance for the design of high-speed displacement and catamaran hull forms.

The vortex ring is an essential and ubiquitous phenomenon that has been rather neglected in aerodynamics and technology, perhaps because it is usually construed, unfortunately, as a mere exercise in old-fashioned mathematics. The existing venerable theories of this phenomenon are at once little known, difficult, uncoordinated, insufficient and inconsistent. They are reviewed, modified and combined, and are thus made ready for the long-overdue experimental tests. An essential mathematical preliminary, the theory of straight vortices, is discussed.

A compilation of 60 papers on hydrodynamics is presented.

The problem is considered of a wing with rectilinear plan form swept so that both leading and trailing edges lie within their respective Mach cones; moreover, the Mach lines from the trailing edge apex intersect the leading edge. Formulas and design charts are presented for the lift in such a case, based on approximate formulas for the lift distribution developed in NACA TN 1991, l949.

An investigation has been made to determine the effects of airspeed and angle of attack on the lift, drag, and pitching moment of a shrouded-propeller model, having a shroud length of about two-thirds the propeller diameter, over an angle-of-attack range from 0 deg to 90 deg. Tests were made of the complete model with the propeller operating and also of the shroud and motor combination with the propeller removed. The effect of inlet-lip cross-sectional radius on the static-thrust characteristics was also studied. These tests were made in connection with the design of a vertical-take-off free-flight model and the results are presented herein without analysis as it is felt that they may be useful in the design or analysis of other aircraft.

The results of an investigation in the NOL 40 X 49 cm aeroballistics tunnel no. 1 to study the static stability and drag of the low-drag bomb at subsonic and supersonic speeds. The following tests were made: (a) study of configurational changes designed to reduce the yaw of the bomb; (b)drag of the 250-pound bomb with supporting lugs; and (c) stability of an 8-fin bomb with reduced fin span to improve the ground clearance problem.

Experimental studies involving velocity profile measurements and polymer diffusion measurements were made in a plane boundary layer with length varying up to 40 ft, thickness varying up to 15 inches, and Reynolds number varying up to 8 x to the 7th power. Aqueous solutions of Polyox WSR-301 of 250 to 2000 ppm were injected tangentially at the boundary near the origin of a boundary layer having a stream velocity of 18 fps. Diffusion of the polymer from the boundary up into the boundary layer was evaluated from profiles made by sampling with withdrawal tubes located at various stations along the flow axis. A fluorescent marker dye was used for the evaluation. Velocity measurements served to define the profile and permitted profile extrapolation to the boundary for boundary shear evaluations. The maximum drag reduction of 35 per cent over a 40-ft boundary length exposed to V = 18 fps occurred with an injection of 0.004 lb/sec of polymer per foot width, which resulted in a downstream wall concentration of about 30 ppm. A flush-mounted hot-film sensor was calibrated for both water and polymer flows in a gravity-flow pipe facility. The calibration curve was influenced by the addition of polymer. Measurements of the zero crossings and frequency spectra of the turbulent fluctuations, as well as velocity profiles, were made for various polymer concentrations in the commercially rough pipe. Zero crossings were found to correlate with the square root of the wall shear stress. (Author)

A new technique to accurately measure low level forces and its application to the determination of drag coefficients in rarefied hypersonic flow are described. Preliminary results are presented for cylinders and spheres at M = 8 in the transitional and near-free-molecule flow regimes. (Author)

A linearized theory is presented of three-dimensional cavity flow past a vertical surface-piercing strut, the cavity being vented to the free surface. The linearization stems from the assumption that both the strut and the cavity to its rear are sufficiently thin for their effect on the flow to be describable in terms of thin-body theory. Accordingly, the linearized disturbance potential is represented by a set of sources - with density function proportional to some thinness parameter -distributed over a domain in the common vertical longitudinal midplane of the strut and cavity. Both the shape of this domain and the source-density function are only partially specified and it is their simultaneous determination that constitutes the central problem of the theory. Mathematically, this problem is equivalent to the solution of a certain two-dimensional integral equation, subject to two side conditions. The linearized formulation indicates that in the case of thin struts whose chord-length and draft are of the same order of magnitude, any flow-speed high enough for the strut to be vented down to its full depth is also high enough for the linearized disturbance potential to satisfy the infinite-speed linearized free-surface condition with good approximation.

On the basis of slender-body theory, an analysis is presented for predicting the shape and aerodynamic characteristics of one-lobed delta parawings at combined angles of attack and sideslip. These characteristics in nondimensional form depend only on the tension parameter and the ratio of the sideslip angle to semiapex angle. An extensive set of calculations has been made as a function of these parameters, and the results are presented in tabular form for design purposes. The results agree with previously calculated results for zero sideslip and with delta wing results for large tension parameters. It has been found that for a given wing there is a range of angle of attack and sideslip in which the wing can operate without inducing luffing of the windward leading edge. It appears desirable to operate the wing in this range not only to avoid luffing, but to obtain the advantage of the low induced drag. The one-lobed parawing shows a stable dihedral effect in that the rolling moment due to positive sideslip is negative above the main luffing-boundary. There is negative sideforce at positive angles of attack and sideslip. (Author)

The paper presents an outline of the modernized Newtonian treatment of the variation of parameters method and is limited to the analysis of the inplane perturbations. Cases of normal and tangent, radial and transverse impulses are discussed for elliptic and hyperbolic orbits. Effect of the atmospheric drag at high altitude is also considered. (Author)

Three cases of viscous flow in a circular cylindrical tube containing an infinite line of spherical particles equally spaced along the axis of the tube are considered: axial translation of the particles, flow past a line of stationary particles, flow of fluid and particles under an imposed pressure gradient. The fluid is taken to be incompressible, Newtonian and the linearized equations of creeping flow are used. The case is an idealization of blood flow in capillaries where the diameter of the red blood cells is of the same order as the diameter of the capillary itself. The results may also be of interest in sedimentation, fluidized beds, and groundwater flow. An exact solution in the form of an infinite series of singularities at the center of each sphere is developed and evaluated numerically for a range of sphere radius to tube radius of zero to 0.9. The drag on each sphere, the pressure drop and typical streamline patterns are given. The results show that the drag and pressure drop for a given size of sphere decrease as the spacing between spheres increases and for spacings more than one tube diameter, there is little interaction between spheres. (Author)

The work considers a three-part sequence of problems in fully-cavitating flow theory which have practical applications in the design of hydrofoil vessels. In each problem a two-dimensional, inviscid, incompressible, irrotational flow is assumed. Results in each case include expressions for the physical-plane configuration and the lift and drag coefficients; they are developed by using conformal mapping and the solution to a Riemann-Hilbert mixed-boundary-value problem in an auxiliary half plane. The first part develops a nonlinear solution for a flat plate in an infinite flow field with gravity neglected. The remaining two parts are extensions of part one to consider in one case the effect of a free surface above the hydrofoil, and in the other case, the effect of a transverse gravity field on the initial problem. The use of a digital computer to perform numerical integrations is a feature common to the solution of all three problems. The solution to the gravity-affected case was found from the nongravity solution via a rapidly convergent iteration process. The results in each case agree well with other nonlinear and linear solutions. (Author)

This report presents the results of bare hull resistance tests on a model which represents a candidate hull form for a proposed U. S. Coast Guard medium polar icebreaker. This model has the same form forward of station 7. The tests were oriented toward choice of an optimum afterbody shape. (Author)

This report presents the results of wind tunnel tests of 16 proposed hypervelocity 105 mm projectile configurations. The tests were conducted during September 1962 on a 48% scale model at Mach numbers of 4.0, 4.5, and 5.0 in the Ballistic Research Laboratories Tunnel No. 1. Results are presented as plotted data. All the configurations can be made gyroscopically stable; presently available data indicates that they are also dynamically stable. (Author)

(1) Results of performance tests with the dolphin Notty show no unusual physiological or hydrodynamic performance. The test conditions suggest, however, that hydrodynamic performance was adversely affected by one or more environmental factors. (2) Analysis of cetacean sightings and performance tests reported in the available references indicates that the drag of these animals is significantly lower than expected. Several low-drag hypotheses offer possible explanations. Additional, and more accurate, top-speed measurements are needed, preferably taken under natural oceanic conditions. (3) A brief analysis and summary of the available literature show that several types of free-riding behavior are exhibited by cetaceans. Different explanations for the bow-riding ability of dolphins exist, and the true explanation may be a combination of various explanations. (Author)

A study is presented of the interaction with the solar radiation field of a spinning satellite having long flexible rods. The dynamics of thermal bending of the rods is analyzed, including the effect of vehicle rotation, and the shape, amplitude and phase are calculated. The radiation pressure on the periodically bent rods produces a net average despin torque that depends critically on the phase lag of the thermal bending. The theory is compared with flight data from the Alouette I and S48 satellites, and the agreement indicates that the mechanism studied is the primary cause of despin of these vehicles. A means of preventing despin is proposed. It consists of polished plates mounted on the tips of the rods. The torque produced by the solar pressure acting on them is opposite to that on the rods. The plate area required for complete cancellation of the despin torque is of order 1/4 to 1/2 of the projected rod area. (Author)

This specification establishes the requirements for the performance, test and qualification of the B-2707 (P and W) propulsion subsystem. The Pratt and Whitney JTF17A-20B engine performance data is the primary data for the propulsion subsystem performance specification. Subsystem performance requirements established herein are design objectives for the prototype airplane. Application of these requirements to production airplane design will be established after prototype flight testing and evaluation., See also Rept. No. D6A10113-1, AD-805 654L.

Conventional first-order supercavitating hydro foil theory is reviewed, and it is shown that, by avoiding the usual linearization of the physi cal plane, general expressions for improved force coefficients may be obtained in terms of the con ventional first-order coefficients. Specific examples are given including supercavitating flow about a cambered hydrofoil, a symmetric wedge and a flat-plate hydrofoil with flap. Comparison with exact solutions shows that the improved first order lift is generally within 5%, for angles up to 90. (Author)

Complete papers are presented under the four major headings listed in the title.