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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>THE LIFT DISTRIBUTION ON LOW ASPECT RATIO WINGS AT SUBSONIC SPEED</title>
      <link>https://trid.trb.org/View/159258</link>
      <description><![CDATA[No Abstract.]]></description>
      <pubDate>Thu, 21 May 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/159258</guid>
    </item>
    <item>
      <title>APPLICATION OF HYBRID COMPOSITES TO HYDROFOIL STRUCTURES</title>
      <link>https://trid.trb.org/View/147391</link>
      <description><![CDATA[Studies are presented on application of advanced composites to hydrofoil structural components such as struts and foils. It is shown that to satisfy the strut/foil structural requirements and constraints, the most cost-effective and structurally efficient designs are achieved by using hybrid composites consisting of a combination of high-strength and high-modulus graphite fibers.  Typical curves are presented for determining the various mechanical properties of hybrid composites as a function of the amounts and orientations of the constituent materials.  To make a realistic assessment of efficiency of hybrid composites as applied to hydrofoil structural components, the various mechanical properties of 0.5-in. thick multilayer, multidirectional hybrid composites are evaluated experimentally.  The experimental results for strength and elastic properties of hybrid composites show excellent correlation with predictions and verify the efficiency of these materials as applied to structural components of advanced naval hydrostructures.  Preliminary results are also presented on fabrication and testing of a 60-in. long hybrid composite, tapered box beam structure simulating the forward foil on the PCH.]]></description>
      <pubDate>Thu, 20 Mar 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/147391</guid>
    </item>
    <item>
      <title>LIFT EFFECTS ASSOCIATED WITH DRAG-REDUCING POLYMER INJECTION ON TWO-DIMENSIONAL HYDROFOILS</title>
      <link>https://trid.trb.org/View/66595</link>
      <description><![CDATA[The effect of a boundary-layer injection of drag-reducing additive solutions on the lift and drag of a 10-cm chord, NACA 63A020 symmetrical two-dimensional hydrofoil was investigated for various freestream and injection velocities, foil incidences, and additive concentrations ranging from 50 to 400 ppm of POLYOX WSR 301.  The experimental results demonstrate that the lift of the hydrofoil can either increase or decrease depending upon whether the polymer injection is made on the suction or pressure side of the foil surface, respectively.  In both cases, however, the drag is reduced.  The net result of the injection of the drag-reducing agent is an augmentation of the lift-drag ratio.  The magnitude of this augmentation and its dependence on the freestream velocity, the injection velocity, the concentration of polymer, and the incidence of the foil are analyzed.]]></description>
      <pubDate>Wed, 16 Feb 1977 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/66595</guid>
    </item>
    <item>
      <title>A VALIDATION STUDY OF THE MIXED FOIL CONCEPT FOR HIGH SPEED HYDROFOILS</title>
      <link>https://trid.trb.org/View/30729</link>
      <description><![CDATA[A hydrodynamic validation study of the concept of the mixed foil has been carried out.  A mixed foil is a streamlined hydrofoil equipped with a flap or other device which, above a certain speed, can be activated so as to change the flow around the foil into a supercavitating flow.  At takeoff and at moderate speeds, a mixed foil is operated as a subcavitating foil; at high speeds, it is operated as a supercavitating foil.  During high speed operations, a reduction in the wetted planform area of a mixed foil is proposed.  Two hydrofoils which have as their sections plano-convex foils of thickness to chord ratios of 5% and 6% are used for the study.]]></description>
      <pubDate>Wed, 21 Jan 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/30729</guid>
    </item>
    <item>
      <title>DESIGN AND CALIBRATION OF A DYNAMOMETER FOR MEASUREMENT OF OSCILLATORY FORCES ON HYDROFOILS</title>
      <link>https://trid.trb.org/View/33538</link>
      <description><![CDATA[Modifications in the design of the Rudder Dynamometer of the MIT Variable Pressure Water Tunnel were made, in order to permit measurements of oscillatory forces on hydrofoils. The apparatus involves the measurement of Lift, Drag and Moment for any mean angle of attack and oscillatory angles of attack up to plus minus 4.0 deg.  The dynamometer is provided with Lebow load cells for measurements of Drag and Lift while the measurement of torque is accomplished by foil strain gages applied to a thin wall shaft section.  The signals are amplified, filtered, averaged, rectified and plotted for a posteriori analysis.  The result of the dynamic calibration of the system indicates that a more detailed description of the distribution of the masses and springs of the system is needed to develop a mathematical model that fully simulates its real behavior.]]></description>
      <pubDate>Sat, 18 Oct 1975 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/33538</guid>
    </item>
    <item>
      <title>STRUCTURAL DESIGN CONCEPT OF TAP-1 HYDROFOIL</title>
      <link>https://trid.trb.org/View/28296</link>
      <description><![CDATA[A structural design concept of the TAP-1 foil and strut configuration was evolved and simplified stress analyses were performed in selected critical stress locations. Although conclusive determination of feasibility and establishment of ultimate criteria for optimum structural design and weight definition must await more sophisticated structural analyses, this preliminary study indicates that it will be feasible to ultimately produce a structurally adequate design capable of withstanding anticipated maximum load conditions. /Author/]]></description>
      <pubDate>Sat, 18 Oct 1975 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/28296</guid>
    </item>
    <item>
      <title>DETERMINATION OF OVERLOADS DURING THE IMPACT OF A PROFILE ON THE SURFACE OF A LIQUID</title>
      <link>https://trid.trb.org/View/40339</link>
      <description><![CDATA[For strength calculations of subaqueous and surface hydrofoils, it is necessary to know the magnitude of overloads during their impact against the free surface of the liquid.  Theoretical and experimental results are presented regarding the determination of impact overloads when a flat plate falls upon the free surface of a liquid. The possibilities of an approximate modeling of this phenomenon are pointed out.]]></description>
      <pubDate>Tue, 30 Sep 1975 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/40339</guid>
    </item>
    <item>
      <title>DIVERGENCE ANALYSIS OF SWEPT HYDROFOILS--COMPUTER PROGRAM (SWDIVRG)</title>
      <link>https://trid.trb.org/View/16490</link>
      <description><![CDATA[A systematic approach is described by which divergence characteristics of swept or unswept hydrofoils may be calculated.  The computer program, called SWDIVRG, developed to do the calculations, makes use of a lumped-parameter approach, resulting in a matrix solution of the system.  The bending and torsional displacements at any of N stations along the hydrofoil span can be calculated at speeds less than divergence.  Bending and torsional moments can be calculated for the condition of cantilever-beam constraints. The divergence speed is principally computed by an eigenvector iteration scheme.  A convenient formulation and a plot are provided for estimating the hydrodynamic loading parameters for finite-span, surface-piercing hydrofoils. Also, a useful closed-form divergence formulation, which considers submergence level, has been derived for the special case of a uniform cantilever strut or foil.  Test calculations of airfoil models and one hydrofoil model, using both SWDIVRG and the closed-form solution, show good agreement with experimental model-divergence speeds.]]></description>
      <pubDate>Mon, 15 Jul 1974 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/16490</guid>
    </item>
    <item>
      <title>PRESSURE CHARACTERISTICS AND CAVITATION ON AN OSCILLATING HYDROFOIL</title>
      <link>https://trid.trb.org/View/18552</link>
      <description><![CDATA[Unsteady cavitation that results from the non-uniformity of the flow field renders evil influences on marine propellers. It has been a general experiment for the investigation on such problems to observe unsteady cavitation in a flow field analogous to a wake pattern.  At the time being, however, quantitative information cannot be derived from such kinds of experiment, and explanations of unsteady cavitation are likely to be qualitative, which can sometimes give us erroneous conclusions.  The most basic and fruitful quantity for the study of cavitation is the pressure distribution on an unsteady hydrofoil in non-cavitating condition. With this quantity we can clarify unsteady cavitation more rigorously. This paper deals with two-dimensional hydrofoils pitching simple-harmonically.  With this simplification pressure distributions can be directly measured, and can be calculated by the use of unsteady wing theory.  These pressure characteristics have intimate relations with the real cavitation phenomena that were observed by high-speed motion pictures.  Principal conclusions obtained are as follows:  1. The oscillatory flat-plate-wing theory shows good agreements with experiments when a rigorous correction is made for the steady component.  2. Characteristics of cavitation on a pitching hydrofoil can be explained by the time-dependent pressure distribution calculated by the unsteady wing theory.  3. Unsteadiness of pressure field strongly affects the process of the collapse of cavity. Increase of unsteadiness will lead to serious erosion.  4. Maximum length of unsteady cavitation on two-dimensional pitching hydrofoils tends to be shortened with the increase of reduced frequency up to 1.0.]]></description>
      <pubDate>Mon, 18 Mar 1974 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/18552</guid>
    </item>
    <item>
      <title>NUMERICAL COMPUTATIONS OF SUPERCAVITATING HYDROFOILS OF PARABOLIC SHAPE WITH WU AND WANG'S EXACT METHOD</title>
      <link>https://trid.trb.org/View/10641</link>
      <description><![CDATA[Wu and Wang in 1963 proposed a method to solve a system of nonlinear integral equations obtained to determine the supercavitating (s/c) flow past arbitrary hydrofoil shapes in which a functional iterative method was used.  The application of the method is presently concerned with arbitrary-shaped s/c hydrofoils, especially with those having rounded leading edges, since there have been no such successful results up to date.  The rounded nosed body in the present paper was a parabolic strut and the position of the upper cavity separation point and the body thickness were changed in several ways while the cavitation number was fixed to be zero throughout the investigation. (Modified author abstract)]]></description>
      <pubDate>Thu, 28 Feb 1974 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/10641</guid>
    </item>
    <item>
      <title>OPTIMIZATION OF FORWARD FOIL LIFT CONTROL FOR AG(EH) HYDROFOIL CRAFT. VOLUME I: HYDRODYNAMICS</title>
      <link>https://trid.trb.org/View/9966</link>
      <description><![CDATA[The report presents the foil and craft characteristics required by the Grumman Specific Linear Optimal Control Program for hydrofoil craft (SLOCOP). The characteristics are presented in generalized form, compared with certain experimental measurements, and evaluated for the AG(EH). The prediction confidence level is deficient in three significant areas: hinge moment, particularly for flaps; unsteady loading, particularly for orbital motion; and flap cavitation boundaries.  SLOCOP trending studies are underway to establish the sensitivity of the autopilot design to the unsteady loading representation employed.  These studies are intended to identify those unsteady loading responses for which further experimental effort is required for confident autopilot design.  (Author)]]></description>
      <pubDate>Wed, 14 Nov 1973 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/9966</guid>
    </item>
    <item>
      <title>OPTIMIZATION OF FORWARD FOIL LIFT CONTROL FOR AG(EH) HYDROFOIL CRAFT. VOLUME II: CONTROL</title>
      <link>https://trid.trb.org/View/9967</link>
      <description><![CDATA[The report summarizes the development, to date, of a linear optimal plant plus controller model for hydrofoil craft. Optimization relative to quadratic performance indices is performed on a control system using restricted state feedback. Application is made to an AG(EH) longitudinal control system with fixed pitch and height gains.  The model is driven by a discretized two dimensional Pierson-Moskowitz sea (steady wind of 26 kts) comprised of 13 spectral components. Vehicle responses and control system gains are trended relative to craft speed and heading for fixed sea state.  Implications regarding control system structure are reviewed.  (Author)]]></description>
      <pubDate>Wed, 14 Nov 1973 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/9967</guid>
    </item>
    <item>
      <title>SELECTING A SCHEME TO CALCULATE WING SYSTEM STRENGTH IN RAKETA-TYPE HYDROFOIL BOATS</title>
      <link>https://trid.trb.org/View/936</link>
      <description><![CDATA[An analysis is given of several simplest force schemes for calculating the dynamic strength of Raketa-type hydrofoils under the effect of impact loads occurring during sailing in rough water. Both numerical and illustrative data are given to substantiate the hydrofoil calculation scheme recommended by the authors.]]></description>
      <pubDate>Mon, 07 May 1973 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/936</guid>
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