Abstract: A tension sensor includes a planar tab having a first and second side, first and second end sections and an aperture through each of the end sections. A first strain gage is attached to the first side of the tab. The first strain gage has a tension grid aligned to a longitudinal axis of the tab and a cross-tension grid perpendicular to the tension grid. A second strain gage is attached to the second side of the tab. The second strain gage has a tension grid aligned to the longitudinal axis of the tab and a cross-tension grid perpendicular to the tension grid. The first strain gage and second strain gage are wired in a Wheatstone bridge in which the tension grid and the cross-tension grid of the first strain gage form one side and the tension grid and the cross-tension grid of the second strain gage form another side.

Abstract: A cable tray and method of use is provided with the cable tray having a bottom extending along a horizontal panel with two opposite side edges. A pair of side walls attaches to the two opposite side edges. A first positioning rack extends between the side walls. The first positioning rack is orthogonal to the tray bottom and the side walls. A second positioning rack extends between the side walls. The second positioning rack is orthogonal to the tray bottom and the side walls. A first foot bar affixes to an underside of the tray bottom. The first foot bar is vertically aligns with the first positioning rack. A second foot bar affixes to the underside of the tray bottom. The second foot bar vertically aligns with the second positioning rack. Each of the first positioning rack and second positioning rack includes cable support apertures.

Abstract: A method for reducing noise in a towed acoustic array includes providing a towed array having a length, diameter, frequency range and tow speed. The relationship between tension in the towed array and wall pressure fluctuation spectral levels is determined. Wall pressure fluctuation spectral levels are related to the noise in the array. An optimal towed array tension is calculated using the determined relationship. Tension is increased to the optimal towed array tension by either provided additional towed array hose or a drogue at the end of the towed array.

Abstract: A towed array is provided with hot-film sensors and anemometer circuitry to calculate the angle of inclination of the towed array in real time during deployment of the towed array in a sea water environment. The hot-film sensors are arranged in pairs along the length of the towed array to increase the sensitivity of the inclination angle determinations and are located flush with an exterior surface of the towed array to minimize interference with the operation of the towed array. The pairs of hot-film sensors determine the local shear stresses on the towed array, and these measurements are converted to inclination angles using an empirically derived look-up table.

Abstract: A towed array is provided with hot-film sensors and anemometer circuitry to calculate the angle of inclination of the towed array in real time during deployment of the towed array in a sea water environment. The hot-film sensors are arranged in pairs along the length of the towed array to increase the sensitivity of the inclination angle determinations and are located flush with an exterior surface of the towed array to minimize interference with the operation of the towed array. The pairs of hot-film sensors determine the local shear stresses on the towed array, and these measurements are converted to inclination angles using an empirically derived look-up table.

Abstract: A towed array is provided with hot-film sensors and anemometer circuitry to calculate the angle of inclination of the towed array in real time during deployment of the towed array in a sea water environment. The hot-film sensors are arranged in pairs along the length of the towed array to increase the sensitivity of the inclination angle determinations and are located flush with an exterior surface of the towed array to minimize interference with the operation of the towed array. The pairs of hot-film sensors determine the local sheer stresses on the towed array, and these measurements are converted to inclination angles using an empirically derived look-up table.

Abstract: A towed array is provided with hot-film sensors and anemometer circuitry to calculate the angle of inclination of the towed array in real time during deployment of the towed array in a sea water environment. The hot-film sensors are arranged in pairs along the length of the towed array to increase the sensitivity of the inclination angle determinations and are located flush with an exterior surface of the towed array to minimize interference with the operation of the towed array. The pairs of hot-film sensors determine the local sheer stresses on the towed array, and these measurements are converted to inclination angles using an empirically derived look-up table.

Abstract: A system and method are provided for detecting an acoustic signal in the presence of flow noise produced by the turbulent flow field that develops about a hosewall of a towed array. Pressure is sensed with pressure sensors at two diametrically-opposed locations at the surface of the hosewall over a period of time. The sensed pressure signals are used to generate an ensemble-averaged cross-spectra which effectively cancels out the flow noise while retaining the acoustic signal associated with a possible target of interest.

Abstract: A method is presented for determining inner and outer boundary layer length scales from a succession of drag measurements of a cylindrical body in order to estimate flow noise and for computational modeling of the dynamics of towed arrays in a fluid medium. A succession of measurements of the total drag on a cylinder under tow at uniform known conditions (flow speed, fluid density, fluid viscosity, cylindrical body geometry) is taken. After each measurement, the cylinder is truncated by a fixed amount, and the process is repeated for the length of the cylinder. The measurements provide a spatially and temporally averaged measure of the mean wall shear stress and momentum thickness, from which the inner and outer length scales can be determined. The inner and outer boundary layer length scales may then be used for estimation of flow noise on towed cylindrical bodies and arrays.

Abstract: A spreader arm aperture generation system for use with a towed array is provided. The spreader arm aperture generation system broadly comprises a plurality of lines and a plurality of hydraulically activated, inflatable tubes for generating horizontal and vertical separation among the lines. Each of the tubes is filled with seawater to a desired pressure to achieve the desired horizontal and vertical line separation. Preferably, each of the tubes is formed from a high strength woven fabric.

Abstract: A method and apparatus are presented for determining turbulent boundary layer thickness. In this method and apparatus, a pair of sensors are mounted to a solid surface interfacing with a fluid at two separate stream wise locations. A voltage output from the pair of sensors is recorded and a real non-dimensional value of a correlation coefficient is computed with measured data from the recorded voltage. A laboratory non-dimensional value of the correlation coefficient is independently determined from laboratory data. The real non-dimensional value is compared with the laboratory non-dimensional value to obtain a boundary layer thickness having a value which minimizes a difference between the values of the real non-dimensional value and the laboratory non-dimensional value.

Abstract: A heat exchange tube includes a tubular conduit for flowing a working fluid therethrough and for conducting heat between the working fluid and a thermal field proximate the tube, and a wire extending axially through the tubular conduit and spaced from an inside surface of the tubular conduit. The invention also provides a method for increasing heat transfer about a tubular conduit by positioning a wire in the conduit.

Abstract: A method and apparatus are presented for determining turbulent boundary layer thickness. In this method and apparatus, a pair of sensors are mounted to a solid surface interfacing with a fluid at two separate stream wise locations. A voltage output from the pair of sensors is recorded and a real non-dimensional value of a correlation coefficient is computed with measured data from the recorded voltage. A laboratory non-dimensional value of the correlation coefficient is independently determined from laboratory data. The real non-dimensional value is compared with the laboratory non-dimensional value to obtain a boundary layer thickness having a value which minimizes a difference between the values of the real non-dimensional value and the laboratory non-dimensional value.

Abstract: A hydraulically activated device for spacing plural towed lines includes a toroidal and inflatable tube member defining an aperture in an opening of the toroid shape. A plurality of connectors each secure a corresponding one of the plural towed lines to the toroidal and inflatable tube member. The toroidal and inflatable tube member is inflated with sea water to a predetermined volumetric configuration suitable to an operating speed range of the towed lines and upon inflation will space the towed lines in a three-dimensional arrangement therearound. A sheath may also be formed around the toroidal and inflatable tube member, the sheath being formed in cross section as a tear drop or similar streamlined shape.

Abstract: A hydraulically activated device for spacing plural towed lines includes a toroidal and inflatable tube member defining an aperture in an opening of the toroid shape. A plurality of connectors each secure a corresponding one of the plural towed lines to the toroidal and inflatable tube member. The toroidal and inflatable tube member is inflated with sea water to a predetermined volumetric configuration suitable to an operating speed range of the towed lines and upon inflation will space the towed lines in a three-dimensional arrangement therearound. A sheath may also be formed around the toroidal and inflatable tube member, the sheath being formed in cross section as a tear drop or similar streamlined shape.

Abstract: A spreader arm aperture generation system for use with a towed array is provided. The spreader arm aperture generation system broadly comprises a plurality of lines and a plurality of hydraulically activated, inflatable tubes for generating horizontal and vertical separation among the lines. Each of the tubes is filled with seawater to a desired pressure to achieve the desired horizontal and vertical line separation. Preferably, each of the tubes is formed from a high strength woven fabric.

Abstract: A heat exchange tube includes a tubular conduit for flowing a working fluid therethrough and for conducting heat between the working fluid and a thermal field proximate the tube, and a wire extending axially through the tubular conduit and spaced from an inside surface of the tubular conduit. The invention also provides a method for increasing heat transfer about a tubular conduit by positioning a wire in the conduit.

Abstract: The present invention relates to a tether retraction device having particular utility with multi-line towed arrays. A system for retrieving and deploying a multi-line towed array having a plurality of array lines has at least one tether joinable between two of the plurality of array lines. A tether retraction device is incorporated into at least one of the array lines for retracting the tether. Each tether retraction device has a tether take-up spool, and a spring driven drive means which causes the tether to wind onto the take-up spool when the array is towed at slow speeds and allows deployment of the tether from the take-up spool when tension in the tether caused by tow forces exceeds the spring force applied by the spring driven drive means.