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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>TIP VORTEX INDEX - AN ENGINEERING APPROACH TO PROPELLER NOISE PREDICTION</title>
      <link>https://trid.trb.org/View/480414</link>
      <description><![CDATA[Experience from high-powered cruise/passenger ships, indicates that the noise generated by propeller tip vortices is much more important for inboard noise than was previously realised.  The article discusses the experience and encouraging results obtained by a study performed in 1995 by a classification society, of available noise measurement results from cruise/passenger ships, in order to identify if the classification society's present prediction method for propeller noise was valid and, if not, to identify the main parameters which were influencing the inboard noise.]]></description>
      <pubDate>Thu, 27 Mar 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/480414</guid>
    </item>
    <item>
      <title>PROPELLER TIP VORTEX CAVITATION NOISE (ON OPV'S)</title>
      <link>https://trid.trb.org/View/456505</link>
      <description><![CDATA[The use of offshore protection vessels (OPVs) for a great number of different types of mission leads to requirements of great flexibility.  An OPV will have to comply with a wide range of performance requirements in order to be able to fulfil the different tasks.  One performance characteristic of interest is noise and vibration.  Propeller cavitation has long been known to be a major source of noise and vibration on board marine vehicles.  For OPVs the problem of cavitation is primarily manifested as interior noise and degradation in the performance of hydro-acoustic sensors.  This paper deals with characteristics of propeller tip vortex cavitation and related noise.  Tip vortex cavitation is highlighted as it is usually the first type of cavitation to occur and as it is hard to avoid at all but very loads speeds.]]></description>
      <pubDate>Wed, 27 Mar 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/456505</guid>
    </item>
    <item>
      <title>A NEW THEORETICAL MODEL OF FORMATION OF VORTEX CAVITATION</title>
      <link>https://trid.trb.org/View/455621</link>
      <description><![CDATA[The paper presents the results of experimental and theoretical research on the modelling of the flow around the tips of propeller blades and of the formation of vortex cavitation.  A new vortex model of the blade is described, which enables detailed studies of the mechanism of formation of vortex cavitation.]]></description>
      <pubDate>Mon, 04 Mar 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/455621</guid>
    </item>
    <item>
      <title>RECENT RESULTS ON TIP VORTEX CAVITATION SCALE EFFECTS AT HIGH REYNOLDS NUMBERS</title>
      <link>https://trid.trb.org/View/455069</link>
      <description><![CDATA[In order to verify the Reynolds extrapolation law on tip vortex cavitation (TVC), basic experiments were conducted on two 3.8 area ratio elliptical hydrofoils with a NACA0020 and a NACA16020 cross sections for Reynolds numbers reaching 8.2x106.  Critical cavitation numbers, axial and tangential velocity profiles of the tip vortex were measured.  The NACA0020 foil displays much larger desinent cavitation numbers as well as larger tangential and axial velocities compared to the NACA16020.  This is due to the increase of the lift coefficient, caused by the change of the cross section.  The influence of the Reynolds number on TVC and its dependence with the angle of attack of the foil are determined.  It is shown that the desinent cavitation number scales with the Reynolds to the power 0.4 and the square of the lift coefficient.]]></description>
      <pubDate>Wed, 28 Feb 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/455069</guid>
    </item>
    <item>
      <title>DETERMINATION OF THE TURBULENT DIFFUSION PARAMETER IN THE TIP VORTEX OF A NACA 0015 FOIL</title>
      <link>https://trid.trb.org/View/455089</link>
      <description><![CDATA[No abstract provided.]]></description>
      <pubDate>Wed, 28 Feb 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/455089</guid>
    </item>
    <item>
      <title>NEAR-FIELD BEHAVIOUR OF A TIP VORTEX</title>
      <link>https://trid.trb.org/View/455129</link>
      <description><![CDATA[The near-field behaviour of a tip vortex trailing behind a low aspect ratio wing, attached to an axisymmetric body, is investigated in this paper.  This study was performed in a tow tank and involved the use of particle displacement velocimetry. Evolution of the tip vortex was studied by mapping its instantaneous lateral velocity at several consecutive axial locations.  The axial velocity distribution was also measured. Experiments were repeated at various Reynolds number and incidence angles.  Repeatability was also examined at the same conditions.  The results indicate that roll-up is almost complete at the trailing edge and that less than 66% of the root circulation is entrained into the vortex.  At Rec=2.2x105, the results are steady, and the spatially averaged tangential velocity agrees well with the existing models.  At Rec<105 the entire flow structure, including the overall circulation, fluctuates from one experiment to the next.  The tangential velocity profiles seem to be dominated by secondary vortices located primarily outside the vortex core.  Axial variations in the flow structure along the parallel middlebody, during the same run, are limited to the location of these secondary vortices. The vortex is observed to expand in the afterbody region, without a change in its total strength.  For all but one case (Rec=2.2x105 and alpha=10 deg), there is a substantial axial velocity deficit within the vortex core near the trailing edge of the wing.  At Rec<105, the axial velocity deficit increases with incidence angle and decreasing Rec.]]></description>
      <pubDate>Wed, 28 Feb 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/455129</guid>
    </item>
    <item>
      <title>NUMERICAL SIMULATION OF TIP VORTICES OF WINGS IN SUBSONIC AND TRANSONIC FLOWS</title>
      <link>https://trid.trb.org/View/433429</link>
      <description><![CDATA[A multiblock zonal algorithm is used to solve numerically the thin-layer Navier-Stokes and the Euler equations for simulating the flowfields of isolated wings, with particular emphasis on understanding the formation and roll-up of tip vortices in subsonic and transonic flows. Four test cases consisting of wings of different planforms have been considered to examine the influence of the tip-cap shape, tip planform, and freestream Mach number. Comparison of the numerical results with the available experimental data shows good agreement for the surface pressures in the regions where the flow is attached or mildly separated. However, discrepancies exist in regions of massive shock-induced separation in transonic flow and in the immediate vicinity of the wing tip in subsonic flow. In general, a fairly good definition of the formation and roll-up of the tip vortex is demonstrated for all of the cases considered here, subject to the coarseness of the grid in the far field. Finally, the calculated lift, drag, and pitching-moment coefficients agree well with the experimentally determined values, where available.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/433429</guid>
    </item>
    <item>
      <title>EFFECT OF ROUGHNESS ON ROLLUP OF TIP VORTICES ON A RECTANGULAR HYDROFOIL</title>
      <link>https://trid.trb.org/View/433946</link>
      <description><![CDATA[Experiments focusing on the development of a tip vortex on a rectangular NACA-66 have been performed in a towing tank. The study consists of flow visualisation by illumination with a laser sheet and by distributing fluorescing dye in the water. It also includes surface pressure measurements, particularly around the tip. The experiments have been performed with a smooth surface, and by painting a layer of roughness elements with characteristic sizes of 250 and 500 microns. The observations demonstrate that the physical dimensions of the tip vortex are not affected significantly by surface roughness, whereas the surface pressure, particularly just under the tip vortex, changes substantially. This observation leads to the conclusion that an increase in the surface roughness reduces the strength of the tip vortex. The flow visualisation experiments also demonstrate that for all the roughness sizes, the tip vortex dimensions increase with the incidence angle and decrease as the velocity is increased. In addition, the study demonstrates that the flow is unsteady and that the tip region is dominated by multiple secondary vortex structures. A series of sample photographs demonstrating these phenomena is provided.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/433946</guid>
    </item>
    <item>
      <title>SCALING OF TIP VORTEX CAVITATION INCEPTION</title>
      <link>https://trid.trb.org/View/436163</link>
      <description><![CDATA[A practical method for predicting tip vortex cavitation inception of marine propellers is described. Cavitation of tip vortex first occurs when the local pressure inside the vortex reduces to the vapour pressure of the fluid. The minimum pressure in the vortex is reached at the radius of the viscous core. An expression for tip vortex cavitation inception number is derived based on a study of Hsu (1989) with the assumption of power-law circulation distribution. The radius of the viscous core in this approximation depends on the circulation distribution and diffusive action of the fluid viscosity. Accurate determinations of circulation distribution for propellers operating behind ships by purely theoretical means can be quite difficult. In this paper a calculation procedure for estimating tip vortex cavitation inception number is outlined with the aid of model experimental data. Cavitation experiments of various model propeller in simulated full scale wake were carried out in the David Taylor Research Center 36-in variable pressure water tunnel. Experimental data have been extensively analysed and used for tip vortex cavitation inception predictions. some comparisons between the present prediction method and ship trial data are made, with results in good agreement.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/436163</guid>
    </item>
    <item>
      <title>TIP VORTEX/AIRFOIL INTERACTION FOR A LOW REYNOLDS NUMBER CANARD/WING CONFIGURATION</title>
      <link>https://trid.trb.org/View/438721</link>
      <description><![CDATA[The effects of the vortical wake shed by a finite span canard on a low Reynolds number airfoil were examined. Aerodynamic performance was evaluated through direct measurements of lift, drag and 1/4-chord pitching moment. Spanwise static pressure and surface film visualisation data were also acquired. A reduction in the down-stream airfoil drag coefficient and an increase in its lift/drag were noted in the presence of the canard for a wide range of configurations. Static pressure and surface visualisation data provided indication of some of the boundary-layer characteristics responsible for the drag behaviour.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/438721</guid>
    </item>
    <item>
      <title>SOME OBSERVATIONS OF TIP-VORTEX CAVITATION</title>
      <link>https://trid.trb.org/View/439132</link>
      <description><![CDATA[Cavitation has been observed in the trailing vortex system of an elliptic platform hydrofoil.  A complex dependence on Reynolds number and gas content is noted at inception.  A complex dependence on Reynolds number and gas content is noted at inception.  Some of the observations can be related to tension effects associated with the lack of sufficiently large-sized nuclei.  Inception measurements are compared with estimates of pressure in the vortex obtained from LDV measurements of velocity within the vortex.  It is concluded that a complete correlation is not possible without knowledge of the fluctuating levels of pressure in tip-vortex flows.  When cavitation is fully developed, the observed tip-vortex trajectory shows a surprising lack of dependence on any of the physical parameters varied, such as angle of attack, Reynolds number, cavitation number, and dissolved gas content.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/439132</guid>
    </item>
    <item>
      <title>STUDIES OF SCALING OF TIP VORTEX CAVITATION INCEPTION ON MARINE LIFTING SURFACES</title>
      <link>https://trid.trb.org/View/439641</link>
      <description><![CDATA[The roll up of vortex sheet on a lifting surface in early stages is studied.  The structures of tip vortex flow, both in the outer inviscid and inner viscous regions, are examined.  The velocity in the viscous core is determined and used as basis for the prediction of tip vortex cavitation.  Some comparisons between the calculated and measured tip vortex cavitation inception numbers are made, and the results are generally in good agreement.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/439641</guid>
    </item>
    <item>
      <title>STUDY OF JUNCTION AND TIP VORTICES USING PARTICLE DISPLACEMENT VELOCIMETRY</title>
      <link>https://trid.trb.org/View/440292</link>
      <description><![CDATA[No abstract provided.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/440292</guid>
    </item>
    <item>
      <title>THE GRIM WHEEL CAVITATION AND TIP VORTEX. OBSERVATIONS AND CONCLUSIONS</title>
      <link>https://trid.trb.org/View/440839</link>
      <description><![CDATA[Full-scale cavitation of a propeller and a Grim (vane) wheel was observed through several hull windows in front of and above the propulsors.  Initial concerns that propeller cavitation might cause erosion at the Grim wheel where not confirmed during dry-dock inspection.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/440839</guid>
    </item>
    <item>
      <title>LEADING EDGE ROUGHNESS - A WAY TO IMPROVE PROPELLER TIP VORTEX CAVITATION</title>
      <link>https://trid.trb.org/View/440897</link>
      <description><![CDATA[Cavitation has detrimental effects on propeller performance causing high levels of radiated noise for Naval Ships and the effects on the internal environment from vibrations and noise could be very disturbing for Commercial Ships.  Tip vortex cavitation, being the first type of cavitation to appear on most propellers, can be delayed by disturbing the vortex shedding at the blade tips.  In this paper a practical method to delay the tip vortex cavitation is presented together with results from cavitation tests giving the background and some highlights from the development.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/440897</guid>
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