Applied Ocean Physics and Engineering (AOP&E)

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https://hdl.handle.net/1912/10

The Department is a major center for research in fluid mechanics, coastal processes, ocean mixing, acoustics, air-sea interaction, deep submergence, ocean systems and moorings, remote sensing, robotics, certain biological processes, image processing, signal processing and estimation, control theory, and the dynamics of ocean cables.

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Browsing Applied Ocean Physics and Engineering (AOP&E) by Issue Date

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  • Technical Report
    Preliminary report CHAIN #11 : 22 February - 22 March 1960
    (Woods Hole Oceanographic Institution, 1960-07) Hays, Earl E.
    The second half of CHAIN Cruise #11, 22 February until 22 March, 1960, is detailed as to type of measurements made with their specific locations. The cruise areas were in the St. Croix region, the Puerto' Rico Trench and the tracks from the Bahamas to Bermuda to Woods Hole. Camera lowerings, lowerings of the thermal probe and accompanying cores, dredging, sound velocimeter lowerings, and acoustic studies of the scattering layer were the special events undertaken while precision bathymetry and towing of the Continuous Temperature Recording Chain were on a watch standing basis.
  • Working Paper
    Tests of propellers for Alvin side propulsion units
    (Woods Hole Oceanographic Institution, 1967-07) Sharp, Arnold G. ; Sullivan, James R.
    Full scale dynamometer tests were run on a series of unshrouded propellers in the range of propeller diameters considered practical for use on the side propulsion units of the research submarine ALVIN. Measurements taken included static thrust, torque, and RPM for various values of hydraulic power input to the driving motor. In other tests, propellers having 14 inch diameter and 20 inch pitch (the present ALVIN configuration) were compared for static thrust as follows: conventional blade shape, unshrouded; conventional blade shape in ALVIN flow-accelerating nozzle unit; square-ended blades in ALVIN nozzle unit. Recommendations are given concerning the proposed new ALVIN side propulsion units.
  • Technical Report
    Deep-sea corehead camera photography and piston coring
    (Woods Hole Oceanographic Institution, 1969-03) McCoy, Floyd W. ; von Herzen, Richard P. ; Owen, David M. ; Boutin, Paul R.
    Cameras were mounted in a newly designed corehead of a piston corer and used to photograph coring operations during 36 stations on CHAIN cruise 75 and 28 stations on ATLANTIS II cruise 42. Through the analysis of these photographs, the deep-water operation of a piston corer during its descent, tripping, impact with the bottom, and ascent has been studied, providing information on the corer's stability, effectiveness in obtaining a bottom sample, and influence on the nearby sea-floor. Accurate determinations of the amount of penetration were possible, allowing comparisons to be made with the more indirect methods of determining penetration and with the length of core recovered. Sediment clouds produced by bottom currents were noticed in many of the bottom photographs. A number of suggestions are made for future piston coring operations. The corer descends with little rotation and swinging. Free-fall and penetration generally take place in less than 5 seconds, with a rotation of 20-60° and an increase of about 6° in vertical deviation. During penetration, the corer disturbs the surrounding sea floor, producing both mounds and depressions around the core barrels. While resting in the bottom, the corer is very stable although some wobbling does occur. Considerable rotation takes place during both pull-out and ascent; frequent sediment discharges from the piston corer occur. No consistent relationship was found between the amount of penetration and the length of core recovered, and thus with the degree of core shortening. Comparisons between piston and pilot cores indicate that the piston cores have been shortened and disturbed relative to the pilot cores, and that as much as a meter of the upper portion of the piston core has been lost. The position of the mud-mark appears to be a reliable indicator of the amount of penetration; estimates by extrapolation of the thermal gradient to the surface are less reliable. The vertical deviation of the corer in the bottom does not influence the amount of penetration. Stratigraphic dips in the recovered cores correspond poorly to this vertical deviation in the bottom.
  • Technical Report
    Hand tools and mechanical accessories for a deep submersible
    (Woods Hole Oceanographic Institution, 1969-05) Winget, Clifford L.
    This report presents the design and construction details for various mechanical hand tools and accessories used by a manned deep submersible. The tools require the use of a mechanical manipulator, and were designed specifically to improve the scientists capability of obtaining deep ocean geological data and biological specimens.
  • Technical Report
    Analysis & experimental evaluation of single point moored buoy systems
    (Woods Hole Oceanographic Institution, 1969-05) Berteaux, Henri O. ; Walden, Robert G.
    This report reviews the analysis and the evaluation of surface buoy systems performed in the Engineering Department of the Woods Hole Oceanographic Institution in 1968. The buoy systems considered are single point moored, taut and compound consisting of wire and synthetic ropes, The first part of the report describes the forcing functions and the system response as measured in situ during and after launching, The second part presents the results of the mooring line components testing and evaluation programs performed at sea or in laboratories. The third part briefly outlines the present development in telemetry transmission of scientific and engineering information, It is believed that this systematic engineering effort is an important factor in the continuous improvement of the reliability and performance of the deep sea buoy systems used in scientific measurements programs.
  • Technical Report
    Experimental stress analysis of model of emergency forebody release device used in deep diving research submarines Alvin, Sea Cliff and Turtle
    (Woods Hole Oceanographic Institution, 1969-08) Sharp, Arnold G. ; Sullivan, James R.
    Tests were conducted on a full-scale model of the emergency forebody release used in the deep-diving submarines ALVIN, SEA CLIFF and TURTLE. The model was machined from metal to the same dimensional tolerances as the prototype. Resistance strain gages, attached to the model, permitted measurement of forces on component parts of the device. Of primary concern was the bending stress which might be set up in the release operating shaft when the submarine is submerged in an inclined position. Tests were arranged to simulate three possible conditions of loading of the release device at a 30 degree vehicle list angle: case (1) righting moment of inclined forebody resisted by release components only; case (2) righting moment resisted by release with assistance from lower guides; and (3) righting moment resisted by couple set up by release and rubber support ring. Test results show that shaft bending stresses (for ALVIN) are high (200,000 psi) for the case (1) condition, lower (400,000 - 90,000 psi) for case (2) and essentially zero for case (3). The conclusion is that the present forebody release design is adequate for all submarine attitudes encountered in normal operation, provided the vehicle has been assembled so that contact between sphere and rubber ring is assured at all times.
  • Technical Report
    Dynamic analysis of a launch and recovery system for a deep submersible
    (Woods Hole Oceanographic Institution, 1969-12) Vandiver, J. Kim
    An analysis of the motion of a docking platform for a deep submersible is presented. The problem is defined as a docking platform, or cradle, suspended beneath a surface vessel by elastic elements, composed of cable, chain, or similar material. The analysis attempts to predict the motion of the cradle in response to sinusoidal motion of the surface vessel.
  • Technical Report
    Torque tests of a full size model of the Alvin/AUTEC emergency sphere release
    (Woods Hole Oceanographic Institution, 1970-11) Sharp, Arnold G. ; Sullivan, James R.
    Laboratory torque tests were perfoirmed using an actual emergency sphere release shaft of the type used in the research submarines ALVIN, SEA CLIFF and TURTLE. A test fixture was constructed which permitted laboratory simulation of the side (squeezing) forces applied to the release shaft came as a result of forebody buoyancy. Estimated full-scale side forces were applied to the cam by a laboratory compression testing machine, and the torque required to rotate the shaft was measured. Tests were run with contacting surfaces (a) clean and dry, (b) greased, and (c) immersed in sea water. From the test results, values of release torque were calculated for the submarines in question. Coefficient of friction values of the contrating materials (Monel K-500 on phosphor bronze) also are reported.
  • Thesis
    Drag coefficients of vibrating synthetic rope
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1971-09) Charnews, Daniel Paul
    The drag, amplitude, frequency tension, diameter and length of synthetic ropes vibrating because of vortex-induced forces, and net vibrating at different tensions were measured. Photographs were taken of the vortices. Drag coefficients were calculated and plotted against Reynolds Number. The measured frequency is compared with data from other sources. The measured diameter is compared with that calculated from conservation of volume.
  • Technical Report
    Motion sensitivity of flame ionization detectors
    (Woods Hole Oceanographic Institution, 1972-05) Gularte, Ronald Carl
    A portable gas chromatograph, using a single flame ionization detector, was constructed. The unit was tested for response to surge, sway and heave accelerations up to 0.3g. Also the detector's response was studied for roll and pitch up to 25 degrees with periods ranging from 3 to 20 seconds. The effect on the detector's response of variation in hydrocarbon concentrations in the parts per million range was investigated and response increased with increasing concentration. Samples containing 1, 10, 100, 1000, and 10,000 parts per million dodecane were analyzed, and under the higher accelerations trace distortion was evident for concentrations below 10 parts per million. Stationary isothermal chromatograms of a normal alkane sample (nC6 - nC32) were compared with those obtained under the various test conditions and no detectable difference in peak area (which represented approximately 1 microgram of the particular hydrocarbon) or retention time was evident. The limits of detection for the Aerograph detector were found to be 21.8 x 10-6 mg/sec for a 30 degree roll, 29.1 x 10-6mg/sec for 20 degree pitching and 21.8 x 10-6 mg/sec for a 0.6g heave acceleration. For the range of translational and angular accelerations that might be expected on a platform at sea, it was found that medium resolution gas chromatography using a flame ionization detector can be conducted, but in the trace analysis region, trace distortion can be expected.
  • Technical Report
    An experimental analysis of the dynamics of a submerged tethered cradle in a seaway
    (Woods Hole Oceanographic Institution, 1972-06) Cohen, Jay Martin
    Submerged recovery of small submersibles by means of surface tethered platforms offers the possibility of operations in sea states higher than is now possible using surface recovery means. The Woods Hole Oceanographic Institution's submersible support catamaran LULU has such a tethered system. The system consisting of cradle, chains, and hoist is designed to recover DSRV ALVIN at a depth of 100 feet, and then lift the submersible rapidly through the air-sea interface. Scientific commitments as well as possible damage to the cradle and/or ALVIN, and danger to personnel have prevented full scale recovery experiments. A 1/40 scale model of the catamaran, chain and cradle was constructed to investigate cradle heave and pitch response in regular sinusoidal waves. Model tests were conducted at the Massachusetts Institute of Technology Tow Tank Facility and data was recorded electronically and photographically. Test runs were made at various ship speeds, cradle depths, wave heights, wave lengths, and cradle suspension modifications. Results indicate that for the existing system, cradle pitch and heave is only slightly attenuated over catamaran response at speeds less then 3 knots (full scale). By decreasing the number of cradle suspension points, and varying hoist resiliency and cradle added mass characteristics, cradle motion can be substantially reduced over catamaran motion.
  • Technical Report
    Investigation into the feasibility of detecting salt fingers optically
    (Woods Hole Oceanographic Institution, 1972-08) Albro, Carl S.
    During the last decade there has been increasing interest in discovering the existance of salt fingering in the ocean. The purpose of this investigation was to determine the feasibility of optically detecting salt fingers. Theoretical calculations were conducted on the angular deviation and displacement of parallel light rays propagating through an ordered salt finger model. It is assumed that salt fingers are square cells (one centimeter) with a checkerboard pattern of cells having high and low indices of refraction. The amplitude of index of refraction, above and below the overall average, was assumed to be between 5 X 10-4 to 5 X 10-6. From the computer work it was concluded that an optical method that detects displacement or intensity would have more promise of finding salt fingers in the ocean than an optical method that detects angular deviations. From the computer results and experimental shadowgraph investigations conducted by others, it was concluded that a shadowgraph method is the most promising optical approach to use for detection of salt fingers. Depending on the strength of the salt fingers, the optimum distance between the fingers and the shadowgraph screen may be as far as one to three hundred meters to obtain a sharp image. To shorten this optical path a telescope-microscope lens system cal led a "shadowgraph shortener" was used. Salt finger detection experiments were conducted in a large tank of saltwater. An expanded laser beam (5 centimeters) was passed through the salt water and the "shadowgraph shortener" to fall on a ground glass screen which was photographed with a 16 mm movie camera. The weakest salt fingers detected had a salinity gradient of .02 parts per thousand per 6 centimeters. A survey was conducted on the salinity gradients in the Atlantic Ocean using Nansen bottle data from hydrographic stations. The larger salinity gradients found in parts per thousand per 50 meters were only one order of magnitude weaker than the experimental results. An optical salt finger detector was designed using the same basic set-up as used in the experiments.
  • Thesis
    The design of an instrument to measure vertically averaged oceanic currents using geomagnetic electric fields
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1972-08) Poranski, Peter Frank
    A bottom mounted electromagnetic current meter measures the vertically-averaged conductivity-weighted velocity. This measurement complements free-fall relative velocity profiles and is valuable for transport determination and dynamics studies. Such an instrument has been designed to measure the three components of the electric field, Ex, Ey, and Ez. Salt bridges used with switched electrodes permit the induced e1ectromotive forces to be measured with only a short baseline; eight foot arms are planned. The first part of this report covers the theory behind the bottom mounted electric field meter. The second part discusses the design of the instrument as well as a brief description of the prototype bottom mounted electric field meter.
  • Working Paper
    Handbook of oceanographic engineering materials : volume I - metals and alloys
    (Woods Hole Oceanographic Institution, 1972-12) Dexter, Stephen C.
    This handbook is intended to serve as an aid in materials selection to Oceanographic engineers and designers. As such it is intentionally limited to materials that may be used advantageously in the marine environment.
  • Thesis
    The design of a surface launch and recovery fender for DSRV "Alvin"
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1973-09) O'Sullivan, James Francis
    Surface recovery of small submersibles could be made safer for personnel and hardware with the installation on the submersible of an inflatable, pneumatic bumper which acts also as main surface buoyancy. Tne use of such a bumper in the recovery of DSRV ALVIN by her catamaran mother ship, LULU, is the subject of this study. It was determined, from first order analysis of the surge velocities of these two vessels in recovery position in a sea state 6, that any such bumper or combination of bumpers (i.e. bumper on LULU) would have to absorb 10,000 ft.-lbF., of energy. In order to protect the mechanical arm, keep the forces of collision at an acceptable level and retain present surface buoyancy, an increase in ascent and descent time must be tolerated since the uninflated vertical projected area of the forebody must increase. Large trim moments, due to the presence of the air bumper at the bow can be eliminated by use of a partially submerged bumper.
  • Technical Report
    The design, logistics and installation of a SOFAR float tracking station at Grand Turk Island, B.W.I.
    (Woods Hole Oceanographic Institution, 1973-10) Walden, Robert G. ; Berteaux, Henri O. ; Striffler, Foster L.
    The Mid-Ocean Dynamics Experiment (MODE) under the Office of the International Decade of Oceanography, National Science Foundation, included plans for the deployment of long-range SOFAR floats in a two degree square area approximately 400 miles Southwest of Bermuda. The floats are located by AFETR, MILS system hydrophones at Bermuda, Eleuthera and Puerto Rico. An additional station at Grand Turk Island, British West Indies, was requested to provide an expanded and more reliable location. In addition a spare installation was to be provided which could be installed within relatively short notice at Eleuthera or Puerto Rico if required. The design, logistical considerations and installation of the Grand Turk Island station are documented in this report.
  • Technical Report
    An acoustic navigation system
    (Woods Hole Oceanographic Institution, 1974-12) Hunt, Mary M. ; Marquet, William M. ; Moller, Donald A. ; Peal, Kenneth R. ; Smith, Woollcott K. ; Spindel, Robert C.
    This report describes a system for underwater acoustic navigation developed, and in use, at the Woods Hole Oceanographic Institution. It includes a brief discussion of the electronic components, operation, mathematical analysis, and available computer programs. There is a series of supplementary Technical Memoranda containing more information on various aspects of the system. We believe that this kind of documentation is more flexible and better meets the needs of potential users than including all technical details in one large volume. These are not final or definitive reports; acoustic navigation capabilities will continue to evolve at W.H.O.I. for some time. Acoustic navigation provides a method of tracking a ship, and an underwater vehicle or instrument package (‘fish’), in the deep ocean. Acoustic devices attached to the ship and fish measure the length of time it takes a sound pulse to travel to acoustic transponders moored on the ocean floor. If the transponder positions and the average speed of sound are known, the ship or fish position can be found.
  • Thesis
    Analysis of a high resolution deep ocean acoustic navigation system
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1975-01) Durham, James Leighton
    A high resolution acoustic navigation system for ocean use is being developed at the Woods Hole oceanographic Institution. The system can yield navigation fixes with respect to a bottom moored reference net with accuracies (on a fix to fix basis) of a few centimeters. In order to use the system to best advantage a survey is required to determine precisely the relative positions of the net elements. Each element combines a pulse transponder with a continuous wave (CW) beacon. Accumulated phase (Doppler shift of the CW beacon) between survey points is measured as well as acoustic travel times between survey points and transponders. Non-linear regression techniques are employed to develop a maximum likelihood estimator for net element positions based on these phase and travel time measurements. An approximate error covariance matrix is generated and an optimum choice of survey points is indicated., The combined system, using these selected locations for performing the survey, can yield reference mooring coordinates with error of ±1 meter. Improved precision appears to be limited by inaccuracies in the pulse and Doppler measuring system.
  • Thesis
    Creep buckling of shells of revolution loaded under uniform external pressure
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1975-01) Sullivan, Paul Francis
    A theoretical investigation is undertaken into the creep instability of two common shells of revolution, the infinitely long cylinder and the complete sphere. The linear and non-linear visco-elastic material idealizations are used in the various theoretical procedures. The critical buckling time is greatly influenced by the parameter a/h ratio, magnitude of initial imperfections and material selection. The spherical shell has a lifetime longer than the cylindrical shell having the same a/h ratio, initial imperfections and material constants, while the critical mode numbers are the same.
  • Thesis
    Structural evaluation of fixed offshore platforms
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1975-01) Vandiver, J. Kim
    In fixed offshore structures, damage incurred below the waterline is often difficult to detect, but significant enough to be the source of a subsequent massive failure. A technique is described that can be used to detect subsurface structural failure by detecting changes in the natural frequencies of the structure. One tower aas extensively studied; the dynamic measurement and analysis techniques are described. A parallel computer model of this tower was used to simulate the effect of removal of structural members on natural frequency. The parameters which determine the level of minimum detectable damage are discussed. Experimental data correlating wind and wave height spectra to observed structure response is presented. Statistical Energy Analysis is introduced as a method for predicting the dynamic response of offshore towers to random waves. The method is superior to the classical random vibration approach, in that it does not require the calculation of the wave force spectrum from the wave height spectrum, thus eliminating the calculations and assumptions common to the frequently used Morrison wave force equation. SEA is also applicable to a broad range of fixed and floating structures.