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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>
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      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>FLOW DEFLECTORS-A CURE FOR VIBRATION</title>
      <link>https://trid.trb.org/View/167175</link>
      <description><![CDATA[The paper summarizes work at the National Maritime Institute (NMI) on the use of flow deflectors to cure propeller-excited vibration on two similar classes of single screw, multi-purpose cargo liners operating at service speeds of around 18 knots.  The deflectors were cambered aerofoils of rectangular planform with a span (projection from hull) of about 1/2% of the ship's length and chord about three times the span.]]></description>
      <pubDate>Thu, 21 May 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/167175</guid>
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    <item>
      <title>A METHOD FOR PREDICTING EFFECTS OF PROPELLER-HULL CONFIGURATIONS ON VIBRATORY EXCITATION OF SHIPS</title>
      <link>https://trid.trb.org/View/161218</link>
      <description><![CDATA[An outstanding problem in naval architecture is the selection of the propeller geometry and the location of the propeller in the aperture in order to reduce the sum of the propeller-induced vibratory bearing forces and moments and the hull surface forces and moments to an acceptable minimum.  This paper presents a reliable method for calculating these net excitations for arbitrary stern and propeller configurations.  A computer solution for the propeller and hull excitations has been developed and assessed by comparison with two independent sets of model measurments. The paper describes the physical mechanisms involved in visualisation of the velocity field and outlines the mathematical models employed to represent the propeller in the hull wake and the hull surface.  Although the method is currently limited to non-cavitating propellers, it can embrace the dominating excitations arising from intermittent blade cavitation.  Order from BSRA as No. 54,391.]]></description>
      <pubDate>Thu, 12 Mar 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/161218</guid>
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      <title>PROPELLER INDUCED SHIP HULL VIBRATION: DESIGN STAGE CALCULATION WITH SUFFICIENT ACCURACY AT A REASONABLE COST</title>
      <link>https://trid.trb.org/View/161222</link>
      <description><![CDATA[Analysis of propeller excitation forces and vibration response is discussed in detail with special emphasis on methods for keeping the cost of the analysis on a reasonable level.  Two case studies are presented (A) local vibration of decks in a 80,000-dwt OBO carrier and (B) Deck-house--hull vibration of a 42,000-dwt Ro-Ro carrier.  Order from BSRA as No. 54,392.]]></description>
      <pubDate>Thu, 12 Mar 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/161222</guid>
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    <item>
      <title>STEADY-STATE DYNAMIC LOADINGS AND RESPONSE</title>
      <link>https://trid.trb.org/View/156428</link>
      <description><![CDATA[The mandate of the committee is to report on excitation, damping and response of structures and their component elements.  The following is dealt with: Excitation including propeller-induced-, engine-induced-, and wave-induced exitations; vibration parameters for ship and offshore structures; structural systems including vibration phenomena of ships and offshore structures; vibration limits and criteria; and conclusions and recommendations of the committee.  Order from NSFI as No. 19763.]]></description>
      <pubDate>Wed, 19 Nov 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/156428</guid>
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    <item>
      <title>ADVANCED ANALYTICAL METHODS FOR EXCITING FORCES OF AN ENGINE AND WHIRLING OF A PROPELLER SHAFTING</title>
      <link>https://trid.trb.org/View/161795</link>
      <description><![CDATA[A new concept taking the rigidity of the engine and its foundation into consideration is used to evaluate the excitation forces of the diesel engine.  A method for analysis of the natural frequencies of propeller shaft whirling is outlined.  Vibration response calculations are presented.  The discussion on the paper is included.  Order from NSFI as No. 19837.]]></description>
      <pubDate>Wed, 08 Oct 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/161795</guid>
    </item>
    <item>
      <title>EXPERIMENT ON REDUCTION OF PROPELLER EXCITED VIBRATORY FORCES AND MOMENTS OF A FISHING BOAT BY A WATERJET SYSTEM</title>
      <link>https://trid.trb.org/View/154474</link>
      <description><![CDATA[One method that has been suggested for the reduction of propeller-excited vibration is the addition of a water jet. The Authors here discuss the application of this method to a fishing boat, and describe tests on a trawler model in which a water jet was installed.  It is mentioned that most fishing vessels have pumping capacity that can be utilised in this way, and it may be possible to reduce the wake peak by fitting a water jet at the stern, directed towards the propeller.  In the model tested, that of an ocean-going stern trawler, four circular jets were fitted in this position, directed towards the top of the propeller disc, and a pump was fitted inside the model.  Results of these tests are presented in some detail.  The water jet had a favourable effect; there was reduction of over 20% in thrust variation, and this was supported by theoretical calculations, measured velocity distribution being used in both cases.  The estimated power required for such jets in the full-scale ship was about 82 hp, or about 3% of the main-engine output.  Order from BSRA as No. 52,650.]]></description>
      <pubDate>Wed, 27 Aug 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/154474</guid>
    </item>
    <item>
      <title>VIBRATORY PROPELLER FORCES ON ARBITRARY HULLS</title>
      <link>https://trid.trb.org/View/154020</link>
      <description><![CDATA[An outstanding problem in regard to the design of ships is the selection of the propeller geometry and the location of the propeller in the aperture in order to reduce the sum of the propeller-induced vibratory bearing forces and moments and the hull surface forces and moments to an acceptable minimum.  This paper presents a reliable method to predict these net excitations for quite arbitrary stern and propeller configurations.  A computer solution for the propeller and hull excitations has been developed and assessed for its adequacy by comparisons with two sets of model measurements.]]></description>
      <pubDate>Wed, 27 Aug 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/154020</guid>
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      <title>RESEARCH ON PROPELLER HULL INTERACTION AND ASSOCIATED VIBRATION</title>
      <link>https://trid.trb.org/View/154227</link>
      <description><![CDATA[At a recent three-day symposium organised by the Royal Institution of Naval Architects a joint paper was presented giving a general view on the character and progress of UK research into propeller-hull interaction and associated ship vibration.  The achievements so far can be summarised as follows:  The crucial significance of pressure forces on the hull, generated by unsteady cavitation has been demonstrated and a considerable understanding of the factors determining this cavitation has been reached.  Methods of estimating the excitation forces, mostly by empirical rules, and the structural responses, by both calculations and empirical rules, have been developed.  They are available as useful tools at those stages in the design process where changes are still possible.  Experimental methods of checking any specific design, particularly by cavitation tests, have been developed to reasonable reliability.  In the current joint project, advances are being made especially in the preparation of more comprehensive computer programs for calculating wake flow and propeller cavitation with the support of both basic and specific experiments to ensure a sound foundation and a valid check.  Again, these will be available for application in the early design.]]></description>
      <pubDate>Tue, 22 Jul 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/154227</guid>
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    <item>
      <title>AN OWNERS VIEW OF PROPELLER INDUCED VIBRATIONS</title>
      <link>https://trid.trb.org/View/149766</link>
      <description><![CDATA[After an introduction in which he mentions the difficulty of avoiding propeller-induced vibration and noise in single-screw ships of very high power, and the need to consider, in the initial design stage of ships of conventional as well as high speed and power, the possibility that harmful vibration might occur, the Author (of A. P. Moller, Copenhagen) discusses these problems from a shipowner's viewpoint.  Vibration velocity is more significant than acceleration or amplitude as a vibration parameter, and the inclusion, in the ISOD Draft Proposal "Interim Guidelines for the Evaluation of Vibration in Merchant Ships", of velocity as a parameter for judging vibration levels for frequencies above 5 or 6 Hz, is welcomed.  The question of judging acceptable vibration levels is discussed in some detail, and it is suggested that it would be useful if owners and builders had a reference available containing actual vibration limits, preferably using RMS values of vibration velocities.  The introduction of vibration levels based on the summation and weighting of the vibration spectrum, together with differentiation of acceptable levels according to the purpose of the location within the ship, seems reasonable.  The relationship between vibration and noise is also discussed.  Decision-making in the preliminary design stage is considered with particular reference to single-screw propulsion, and to the choice of a low propeller-speed.  It is mentioned inter alia that some single-screw ro/ro ships built during the last few years have shown that wide flat after-bodies represent a special problem in propeller-induced hull-pressure fluctuations. Shipbuilders today are generally successful in avoiding resonant frequencies, but success has been less certain in estimating and avoiding harmful excitations from the propeller working in a wake.  Some examples of these problems, and their consideration in the initial design phase, are discussed, including the design procedure adopted in a recent project for six 20,000-dwt cargo liners with stern ramps.  Knowledge now being gained from analytic and experimental methods and shipboard measurements should be condensed into guidelines and practical procedures that will enable the ship designer to control the level of propeller-induced vibration from the beginning of the project.  An excellent example of a step in this direction is B.S.R.A.'s "Design Guidance Note on the Avoidance of Propeller Excited Vibration Problems".  Order from BSRA as No. 52,508.]]></description>
      <pubDate>Thu, 26 Jun 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/149766</guid>
    </item>
    <item>
      <title>GENERAL VIEW OF U.K. RESEARCH ON PROPELLER/HULL INTERACTION AND ASSOCIATED SHIP VIBRATION</title>
      <link>https://trid.trb.org/View/149767</link>
      <description><![CDATA[Any attempt at solving the problem of propeller/hull interaction and the associated ship-vibration (the problem generally known as propeller-excited vibration) must take a broad and balanced approach that covers not only the full range of hydrodynamic and structural problems, but also the range of designers' requirements.  This approach is the one used in the U.K., where co-operation between the interested organisations has enabled the PEV (Propeller-Excited Vibration) project to be completed (in Mar. 1977) and the PHIVE (Propeller-Hull Interactive Vibration Excitation) project, due to terminate in June 1980, to be carried out. The latter project is concerned entirely with the hydrodynamic generation of the excitation force, with emphasis on the provision of information and procedures to ensure good hydrodynamic design of hull and propeller.  The Authors (of, respectively, British Shipbuilders, the National Maritime Institute, and B.S.R.A.) describe this work and discuss the results of the PEV project, the stage reached with the PHIVE project, and the objectives underlying both.  The paper is arranged under the headings:--1. Introduction.  2. The General Plan of Research.  3. Work Done and Results Achieved (1--Sea Trials. 2--Mechanical Exciter Trials. 3--Finite-Element Calculations. 4--Scaled Model Tests. 5--Hydrodynamic Calculations).  4. Application to Ship Design.  5. Conclusions.  Under this last heading, it is concluded that, in both hydrodynamics and structural dynamics, substantial advances in guidance for ship designers have resulted from the development of both analytical methods and systematic empirical knowledge.  A brief summary of these achievements is included.  Order from BSRA as No. 52,509.]]></description>
      <pubDate>Thu, 26 Jun 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/149767</guid>
    </item>
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      <title>THE RELATIVE IMPORTANCE OF SHIP VIBRATION EXCITATION FORCES</title>
      <link>https://trid.trb.org/View/149768</link>
      <description><![CDATA[The Authors, of Det norske Veritas, point out that experience has shown that the propeller is the main source of vibration in the after part of the ship, and that ro/ro ships and some other types are even more sensitive to propeller excitation than tankers and other bulk carriers. The importance of the excitation forces transmitted through the shaft, as compared with those transmitted through the water and the hull surface, is then examined in the light of the results of extensive calculations and full-scale measurements.  The paper is presented under the main headings:--1. Introduction.  2. Excitation Forces from Propeller (1--Shaft Forces. 2--Hull Surface Forces).  3. Relative Magnitude of Propeller-Induced Excitation Forces. 4. Dynamic Response of Hull and Superstructure (1--The Mode Superposition Method. 2--Transfer Functions between Excitation Force and Response).  5. The Relative Importance of the Excitation Forces.  6. Correlation between Analyses and Measurements.  7. Conclusions.  Under 7., it is concluded that the forces transferred to the hull surface as pressure fluctuations are, in general, the largest excitation forces; they are mainly the result of transient cavitation on the propeller blades.  Wake variation is a very important factor in cavitation-induced pressure fluctuations, but some remarkable improvements have been obtained by such devices as skewed blades and/or unloaded blade-tips.  As the afterbody lines determine the size of the area exposed to the pressure fluctuations, these fluctuations alone are not a reliable measure of the magnitude of the total hull-surface forces.  Several further conclusions are drawn, and a general conclusion is that propeller forces transmitted through the shafting are of no significance as long as longitudinal and whirling resonances are avoided.  It is also found that the pressure impulses, the fundamental resonant frequency of the superstructure, and the vibration level can be calculated with sufficient accuracy at the design stage.  Order from BSRA as No. 52,510.]]></description>
      <pubDate>Thu, 26 Jun 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/149768</guid>
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      <title>SOME EXPERIENCES FROM VIBRATION EXCITATION TESTS IN THE SSPA LARGE CAVITATION TUNNEL</title>
      <link>https://trid.trb.org/View/149769</link>
      <description><![CDATA[Cavitation Tunnel No. 2 at the SSPA (the Swedish State Shipbuilding Experimental Tank at Gothenburg) has been in operation since 1969.  The Author describes the tunnel, including some modifications that have been incorporated since it was brought into use, and discusses its design philosophy.  The experimental techniques used with the low-speed section of the tunnel, and methods of analysing the results, are described with particular reference to propeller-excited vibration and to the pressure fluctuations at a reference point on the ship-model above the propeller, and the significance of such measurements for the prediction of vibration on the full-scale ship is examined.  The Author also briefly discusses unconventional propellers and stern fins as devices for reducing the amplitudes of the pressure fluctuations.  Some cavitation-tunnel results are presented that indicate the respective amplitude-reductions through unloading the blade tips, skew-back, and fitting stern fins. Order from BSRA as No. 52,511.]]></description>
      <pubDate>Thu, 26 Jun 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/149769</guid>
    </item>
    <item>
      <title>VIBRATION PERFORMANCE OF HIGHLY SKEWED C.P. PROPELLERS</title>
      <link>https://trid.trb.org/View/149771</link>
      <description><![CDATA[The Author, of the KaMeWa company, first summarises the main advantages of highly-skewed propellers, in particular those with controllable pitch, discusses various criteria that have been proposed for estimating the maximum allowable level of the propeller-induced fluctuating pressures acting on hull surfaces adjacent to the propeller, and describes a proposed new criterion, intended to take hull stiffness and dynamic amplification due to resonance into account, which is based on the vibration equation for a single mass system subject to harmonic excitation and damping.  The main part of the paper consists of a presentation and discussion of full-scale results of pressure-pulse, vibration, and noise measurements on ships with KaMeWa highly-skewed c.p. propellers.  The ships are of several different classes, mostly single-screw.  Most of the propellers are the original ones as fitted to the new ships, but some are propellers in which conventional blades have been replaced by the highly-skewed ones to cure vibration problems of ships already in service.  Results of model tests, and a few results from sea trials, are included in which the propeller-induced pressure amplitudes from conventional propellers are compared with those from highly-skewed propellers.  Comparisons are also made between the results of cavitation-tunnel tests, with the propellers fitted to dummy afterbodies, and the corresponding full-scale measurements on some of the ships.  Agreement between model and full-scale propeller-induced pressure amplitudes is quite good, and demonstrates the feasibility of cavitation-tunnel tests as a means of predicting propeller excitation and the possible risk of unacceptable afterbody vibrations.  Several other conclusions and recommendations, based on the results of this work, are included.  Order from BSRA as No. 52,515.]]></description>
      <pubDate>Thu, 26 Jun 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/149771</guid>
    </item>
    <item>
      <title>CAVITATION-INDUCED HULL PRESSURES: A COMPARISON OF ANALYTICAL RESULTS, SHIP AND MODEL MEASUREMENTS</title>
      <link>https://trid.trb.org/View/149772</link>
      <description><![CDATA[The Propeller Excited Vibration (PEV) project carried out by B.S.R.A. between 1974 and 1977 has provided design guidance and experimental and analytical procedures to assist the designer to avoid excessive levels of propeller-induced vibration.  In this paper, the Author (of B.S.R.A.) reports on the outcome of the part of the PEV research that was particularly concerned with the analytical assessment of propeller and wake.  After an introduction in which, some relevant effects of cavitation are discussed, the paper is arranged under the main headings:--The Role of Analytical Propeller Methods in the Design Sequence; B.S.R.A.'s Current Analytical Method; Basic Assumptions; Comparison of Analytical Predictions with Ship Measurements and Model. B.S.R.A.'s current analytical method consists of a program suite conforming, like most analytical methods for estimating hull excitation forces due to the propeller and wake, to a four-module philosophy, and the particular modes of evaluation are (A) Propeller analysis, (B) Determination of cavity geometry, (C) Determination of free space pressure, and (D) Determination of hull excitation force. This analytical method, applied to four combinations of scaled model propeller and wake, has been found to predict, reasonably well, blade rate amplitude of pressure close to the blade tips.  However, the calculated blade-rate pressure components do not show the same fall-off rate (with increasing distance from the tips) as the ship and the model, a tendency which causes an over-estimate in the integration of pressure to obtain the exciting force.  These results indicate that, to obtain reliable estimates of excitation from the calculated pressures, the method requires further assessment and development.  Development can be envisaged in each of the four modules, if ship and model tests can provide a deeper insight into several matters that require clarification.  Order from BSRA as No. 52,516.]]></description>
      <pubDate>Thu, 26 Jun 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/149772</guid>
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      <title>PROPELLER EXCITED VIBRATION-THE PRACTICAL APPLICATION OF THEORETICAL METHODS TO SHIP DESIGN. PART I-EXCITATION</title>
      <link>https://trid.trb.org/View/149773</link>
      <description><![CDATA[Techniques such as the finite-element method, the lifting line and lifting surface theories, and the vortex lattice method now represent, potentially, extremely powerful tools for the mathematical simulation of the propeller/wake interaction problem.  However, an "exact" solution to the problem of predicting propeller-induced excitation forces is not yet possible and is not likely in the immediate future, and the Authors' main purpose is to give a more realistic perspective to the practical applications of these techniques.  In the absence of a better prediction method, the assessment of the capability of an available method must be based on its ability to give an "engineering" evaluation of the probable excitation levels.  In such a context, overall accuracy objectives should be about 25-30%, and current prediction methods can achieve this for most design configurations.  Even with these relaxed objectives, the problem is still complex, and its solution must at present be reached by a hybrid approach in which both model techniques and empirical methods are used in those areas where current theoretical capabilities are deficient.  A prediction capability based on this philosophy must still encompass a number of diverse aspects such as: model testing; velocity wake scaling and induction effects; propeller hydrodynamic and loading models; cavitation models; propeller induced pressure and velocity fields; and solid boundary reflection effects.  At Lloyd's Register, this philosophy has been used in the development of a computer capability for predicting propeller-induced excitation levels, and, anticipating future progress, each of the aspects enumerated has been programmed as a separate module, with a master program linking them to form the complete capability.  This part (Part I) of the two-part paper consists largely of a discussion on each of these modules.  Several conclusions are drawn, and it is suggested that current theoretical methods such as those discussed, though capable of much improvement in certain areas, can give results reliable enough to enable a reasonably confident "engineering" assessment to be made of the probable full-scale excitation levels.  It is also suggested that the most effective use of theoretical techniques lies in the early evaluation and, if necessary, optimisation of the design arrangement, together with model cavitation tests of the final configuration in cases where moderate to high hull surface-pressures are indicated.  Order from BSRA as No. 52,519.]]></description>
      <pubDate>Thu, 26 Jun 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/149773</guid>
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