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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>BILGE VORTEX CONTROL DEVICES AND THEIR BENEFITS IN PROPULSION</title>
      <link>https://trid.trb.org/View/432226</link>
      <description><![CDATA[Multifilar stern flow visualisations of U-shaped models confirmed existing data on cross flow and bilge-vortex separation and gave an improved insight into propeller intake flow characteristics.  In order to reduce the detrimental effects of the cross flow which promotes bilge vortices and affects propeller efficiency, a specially adapted flow-straightening device was used which considerably reduced the power output on the shaft and the propeller thrust and also reduced thrust- and torque fluctuations and wake peaks.  The article includes a general survey of recent research of stern flow with bilge vortices and inherent scale effects and of past full scale experience with a fin system.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/432226</guid>
    </item>
    <item>
      <title>A PRACTICAL ESTIMATION METHOD OF WAKE PATTERN</title>
      <link>https://trid.trb.org/View/441120</link>
      <description><![CDATA[The most important characteristic of the wake pattern of full hulls is that its main part is occupied by the bilge vortex. This characteristic makes it difficult to estimate the wake pattern of such hulls.  The author has tried to develop a practical estimation method of the wake pattern which can be applied to such hulls.  This paper describes its development.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/441120</guid>
    </item>
    <item>
      <title>ON STERN FLOW FIELD OF FULL SHIP FORMS AND INDUCED DRAG DUE TO BILGE VORTICES (PART 2)</title>
      <link>https://trid.trb.org/View/441367</link>
      <description><![CDATA[An investigation of flow characteristics at the stern was made for two stern forms:  one is a newly-developed asymmetric stern of the letter-C-type and the other is its parent stern having the usual form.  Velocity distributions were measured by five-hole pilot tube at the propeller area for the two forms. The flow characteristics, including vorticity distribution, the energy saving mechanism due to inflow rotation, and induced drag, is discussed.  A new formula is presented for calculating induced drag due to longitudinal vortices.  The scale effect of induced drag is also discussed.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/441367</guid>
    </item>
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      <title>BOUNDARY LAYER MEASUREMENTS AND EVALUATION OF VISCOUS RESISTANCE COMPONENTS ON FULL HULL FORMS</title>
      <link>https://trid.trb.org/View/394987</link>
      <description><![CDATA[A three-dimensional turbulent boundary layer on several ship hulls, whose stern forms are changed systematically, is calculated by a simple integral-type prediction method with small crossflow assumption, and is measured by three-hole Pitot tube in a circulating water channel. The viscous resistance components due to streamwise momentum loss in the boundary layer and stern bilge vortices are evaluated by Himeno's method.  The usefulness of the estimation method of viscous resistance is examined in stern-form design problems. A change of the frameline shape at the stern affects not only the crossflow in the boundary layer and the strength of the longitudinal vortices, but also the streamwise momentum loss. The viscous resistance becomes small by reducing the fullness of the stern shoulder.]]></description>
      <pubDate>Thu, 21 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/394987</guid>
    </item>
    <item>
      <title>ON A STERN FLOW FIELD WITH BILGE VORTICES: 2ND REPORT</title>
      <link>https://trid.trb.org/View/396679</link>
      <description><![CDATA[In a previous paper, a simple prediction of velocity distribution around a ship stern was made using the streamline tracing method. The calculation involved the use of the potential pressure field with displacement effect, under the assumption that the fluid is invisid but rotational. In this paper, the calculation is instead carried out based on the use of a modified potential pressure field, with a correction for the pressure gradient perpendicular to the hull surface. Some improvement is obtained. The calculation is also made for the initial value, calculated by three dimensional boundary layer theory.]]></description>
      <pubDate>Thu, 21 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/396679</guid>
    </item>
    <item>
      <title>MEASUREMENT OF WAKE-VELOCITY AT SHIP-MODEL STERN IN FORCED PITCHING MOTION BY USE OF FIVE-HOLE PITOT TUBE</title>
      <link>https://trid.trb.org/View/397175</link>
      <description><![CDATA[Measurements made with a five-hole Pitot tube are used to evaluate three components of unsteady velocity in periodic flow. The frequency response of the whole pressure measurement system is examined in regular head waves. Using the results, the velocity distribution in the stern section of a ship model in forced pitching motion is measured by use of the Pitot tube. The time-mean velocity in pitching motion is found to be larger than that in still water near the propeller position and the bilge vortices in this region are found to become smaller.]]></description>
      <pubDate>Thu, 21 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/397175</guid>
    </item>
    <item>
      <title>BILGE VORTEX CONTROL DEVICES AND THEIR BENEFITS FOR PROPULSION</title>
      <link>https://trid.trb.org/View/400513</link>
      <description><![CDATA[Cross flow at the stern of a ship strengthens bilge vortices and diminishes propeller efficiency. A flow straightening device was investigated and resulted in a considerable reduction in shaft horsepower, propeller thrust, thrust and torque fluctuations and wake peaks. Included is a review of research on stern flow with bilge vortices and inherent scale effects, and of full scale experience with the described fin system.]]></description>
      <pubDate>Thu, 21 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/400513</guid>
    </item>
    <item>
      <title>NUMERICAL SIMULATIONS OF THE VISCOUS FLOW AROUND SHIPS INCLUDING BILGE VORTICES</title>
      <link>https://trid.trb.org/View/403078</link>
      <description><![CDATA[This paper deals with numerical simulations of viscous flow around mathematical ship models generating bilge vortices. The methods used are applied to simulating the flow around several ship models, and results are compared with experiments. General features of the stern flow are adequately predicted from the practical point of view, although some discrepancies are found in details. The paper also describes the influence of propeller action on the viscous stern flow. A propeller is simulated by giving the pressure jump at its position. Propeller-hull interaction is numerically investigated and the results are compared with those of the experiments.]]></description>
      <pubDate>Thu, 21 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/403078</guid>
    </item>
    <item>
      <title>A BILGE VORTEX CALCULATION</title>
      <link>https://trid.trb.org/View/403767</link>
      <description><![CDATA[A slender-body line-vortex potential model of the flow past hull- like blocks at leeway is described. The downstream evolution of the flow is determined by a marching calculation procedure. At each cross flow plane, an iterative procedure is used to solve a transformed problem with simpler boundary conditions. The solution is then conformally mapped to provide a potential solution in the cross flow problem. When bilge vortices cease growing, they are shed and new vortices are allowed to form near the bilge. The lift force is determined by the integration of pressure forces. Important qualitative features of the flow are correctly modeled, but good quantitative agreement is not achieved. The reasons for discrepancies are discussed. Optimism is expressed about the future for this type of model.]]></description>
      <pubDate>Thu, 21 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/403767</guid>
    </item>
    <item>
      <title>CALCULATION OF THE BOUNDARY-LAYER FLOW AROUND THREE SHIP AFTERBODIES</title>
      <link>https://trid.trb.org/View/156171</link>
      <description><![CDATA[A description is given of a differential method for the calculation of the boundary layer on ship hulls, and its application to three slightly different ship afterbodies. The boundary layer equations are solved in a curvilinear coordinate system, together with two turbulence model equations.  The results are compared with experimental data. The correspondence appears to be excellent on the greater part of the hull.  In some regions, differences are present, which result mainly from the neglection of the potential flow-boundary layer interaction.  The prediction of bilge vortex formation is examined, and the incorporation of higher order effects in the method is briefly discussed.]]></description>
      <pubDate>Wed, 08 Oct 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/156171</guid>
    </item>
    <item>
      <title>A STUDY ON SEPARATION VORTICES AROUND A FULL SHIP MODEL</title>
      <link>https://trid.trb.org/View/147720</link>
      <description><![CDATA[In this paper numerical calculations of the motion of the bow bilge vortex and the circulations of the bow and stern bilge vortices are carried out.  The circulations of vortices are obtained by integrating the pressure differences at both ends of the boundary layer involved into separation vortices.  The calculated values agree with the measured values with acceptable accuracy.  Order from NSFI as No. 18525.]]></description>
      <pubDate>Mon, 11 Feb 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/147720</guid>
    </item>
    <item>
      <title>EFFECT OF AFTERBODY FORMS AND AFTERBODY FINS ON THE WAKE DISTRIBTUTION OF SINGLE-SCREW SHIPS</title>
      <link>https://trid.trb.org/View/70597</link>
      <description><![CDATA[The wake distribution is an important parameter regarding propeller-induced vibrations.  The present report is a description of the influence of afterbody form, particularly section shape, upon wake distribution.  Examples are also presented showing how after body fins can be applied to improve unfavourable wake distribtuions.]]></description>
      <pubDate>Wed, 19 Jul 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/70597</guid>
    </item>
    <item>
      <title>BILGE VORTEX SCALE EFFECT</title>
      <link>https://trid.trb.org/View/56976</link>
      <description><![CDATA[It is concluded that when going from model to full scale the bilge vortices move horizontally so that their distance from the centre plane of the propeller disc is reduced by about 25 percent.  This is about half the motion predicted by the "Sasajiima-Tanaka" method for the frictional wake contours.]]></description>
      <pubDate>Fri, 13 Jan 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/56976</guid>
    </item>
    <item>
      <title>INVESTIGATION ON COMPONENTS OF SHIP RESISTANCE</title>
      <link>https://trid.trb.org/View/20733</link>
      <description><![CDATA[The results of a decade of research on the separate measurements of the various components of resistance are summarized. Theoretical bases and equipment and experimental procedures developed for determining the viscous, wave, and bilge vortex resistance, as well as some preliminary results on 'blockage effect', are mentioned. (Author)]]></description>
      <pubDate>Thu, 19 Dec 1974 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/20733</guid>
    </item>
    <item>
      <title>WAKE DISTRIBUTION OF FULL FORM SHIP</title>
      <link>https://trid.trb.org/View/24831</link>
      <description><![CDATA[In order to investigate the wake distribution of full ships, the measurement of the flow around the stern of a 200,000 DWT tanker together with its two model ships, 7m and 30m models respectively, was carried out using 5-hole spherical Pitot tubes.  For both the ship and its 30m models, the measured section was forward to the propeller at a distance of 90% of the propeller diameter, while the 7m model was measured at several additional points, besides the foregoing allocation.  In addition to these experiments, a detailed study of stern flow through boundary layer measurements of the 7m model was conducted with a 3-hole arrow type Pitot tube.  The pressures through the 5-hole and 3-hole Pitot tubes were measured using autobalacing pressure transducers and a digital record system.  The boundary layer measurement revealed the flow in the vicinity of the hull surface, the mechanism and growing process of the bilge vortex.  From the wake measurement it was proven that the complicated flow, otherwise known as a bilge vortex, exists in a ship's wake as well as in its model wake, and a method of estimating the wake distribution of ships from their model is also applicable to full form ships.  Moreover, when this method is applied to the estimation of the flow direction of a ship's wake, the estimated direction will prove itself to be in fairly close agreement with the experimental values.]]></description>
      <pubDate>Thu, 19 Dec 1974 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/24831</guid>
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