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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <language>en-us</language>
    <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>EXPERIMENTAL STUDY ON DEVELOPMENT OF ADD-ON VORTEX SUPPRESSION DEVICE</title>
      <link>https://trid.trb.org/View/480524</link>
      <description><![CDATA[This study proposes a cable with ribbons attached 120 degrees apart.  The ribbons can adjust themselves with the flow coming in any direction.  Experiments were carried out to investigate the effects of the length of the ribbons, and the direction of flows for various uniform velocities.  The experiments were conducted in a circulating water channel.  Flow visualization was carried out using laser sheet beam.  Laser Doppler Velocimetry was employed to measure the velocity field in the wake.  This experiment demonstrates that the attached ribbons can be used to reduce the drag force on a cylinder even when the direction of the flow is not constant.]]></description>
      <pubDate>Thu, 27 Mar 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/480524</guid>
    </item>
    <item>
      <title>DYNAMICS OF A HYDROELASTIC CYLINDER WITH VERY LOW MASS AND DAMPING</title>
      <link>https://trid.trb.org/View/480735</link>
      <description><![CDATA[An experimental facility for the study of the forces and response associated with vortex-induced vibration of a rigid cylinder has been constructed with extraordinarily low normalized mass and normalized damping.  This facility achieves a level of combined mass and damping which is an order of magnitude less than previous studies of this type.  Measurements of the total integrated forces on a static cylinder demonstrate the importance of the end conditions.  By varying the end conditions, the case of vortices shed parallel to the cylinder was compared to the oblique shedding case.  The results show that the mean drag is consistently higher in the parallel shedding case, throughout the range of Reynolds number, whereas the variation in r.m.s. lift is highly dependent on Reynolds number. At Re = 12 000, the parallel case had five times the r.m.s. lift of the oblique case, a ratio which would become larger as the aspect ratio of the cylinder increases.  However, despite this dependence upon Reynolds number in the magnitude of the lift force, the dominant nondimensional frequencies of the lift force were independent of Reynolds number, even in the present case of cellular shedding. The study of the response in the hydroelastic case has brought two previously neglected points to the fore.  The data at very low mass- damping ratio shows that the response has two branches of resonance.  The implication at low mass-damping ratios is that there are actually two distinct levels of resonance, rather than a single one as previously assumed.  The second observation is that the adjustment of the mass ratio affects the response, even when the combined mass-damping ratio is kept constant.  An equation of motion is developed, with inclusion of the inviscid "added-mass" force which will necessarily become important at low mass ratios.]]></description>
      <pubDate>Thu, 27 Mar 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/480735</guid>
    </item>
    <item>
      <title>RECENT ADVANCES IN THE COMPUTATION OF VORTEX INDUCED VIBRATIONS AND THE SHIELDING EFFECT</title>
      <link>https://trid.trb.org/View/456537</link>
      <description><![CDATA[The paper presents some recent results obtained by the computer program VISFLO.  This program computes viscous flow around circular cylinders by the vortex-in-cell method.  The first problem studied is a case with two cylinders that can move independently of each other.  Results are shown which indicates if the cylinders can be expected to collide.  The other type of problem studies is a large array of fixed cylinders.  The aim of the study is to compute the shielding effect in steady flow.  Results are shown for both model scale and full scale cases.  The scaling effect is shown to be very important.]]></description>
      <pubDate>Wed, 27 Mar 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/456537</guid>
    </item>
    <item>
      <title>EFFECTS OF VORTEX EXCITATION ON THE RESPONSE OF FLEXIBLE RISERS</title>
      <link>https://trid.trb.org/View/456538</link>
      <description><![CDATA[A new approach to vortex shedding, incorporating lift forces by a quasi-steady model, is used to evaluate the effects of vortex excitation.  The modelled lift forces are used directly as a part of the external forces in the equations of motion.  The effects of the vortex excitation on the flexible riser are presented by comparing the results derived in analyses with and without lift forces.  Lift forces produce small lateral vibrations of the riser, and cause larger displacements under current and wave loading because of the larger displacements under current and wave loading because of the larger effective drag coefficient.  Even though the vibration amplitudes are modest, the associated bending stresses are not insignificant in the context of fatigue.]]></description>
      <pubDate>Wed, 27 Mar 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/456538</guid>
    </item>
    <item>
      <title>SEARISER FULL SCALE TEST CAMPAIGNS: RISER DYNAMIC BEHAVIOUR UNDER CURRENT AND UNDER SINUSOIDAL TOP MOTIONS</title>
      <link>https://trid.trb.org/View/456539</link>
      <description><![CDATA[Results of extensive tests at sea on a single instrumented riser are presented.  The tests were conducted to examine the validity of existing calculation procedures of riser response to current loading and to investigate the occurance of hydroelastic vibration due to vortex shedding.  It was identified that the riser was vibrating laterally in the first natural mode due to vortex shedding.  Lateral amplitude was 52% of the diameter.  When top of riser executed sinusoidal motion, a lock-in condition occurred at the first and second natural frequency, with the lateral response about 0.50 of the diameter.  The hydrodynamic coefficients calculated from these tests are also reported and show agreement with the published data.]]></description>
      <pubDate>Wed, 27 Mar 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/456539</guid>
    </item>
    <item>
      <title>A GAUSSIAN MODEL FOR PREDICTING THE EFFECT OF UNSTEADY WINDSPEED ON THE VORTEX-INDUCED VIBRATION RESPONSE OF STRUCTURAL MEMBERS</title>
      <link>https://trid.trb.org/View/456549</link>
      <description><![CDATA[In a previous study the authors showed that the expected duration of visit by the windspeed to the critical velocity interval of a structural member is an important time scale in determining the ultimate fatigue damage of the member due to vortex-induced vibration in naturally time varying winds.  In this paper, a Gaussian windspeed assumption is introduced in which the expected duration of visit can be expressed explicitly in terms of simple wind statistics. This assumption is verified with high sampling rate maritime wind data.  The wind statistics necessary for calculation of the expected duration of visit are extracted from the raw wind data.]]></description>
      <pubDate>Wed, 27 Mar 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/456549</guid>
    </item>
    <item>
      <title>RESPONSE OF FREE HANGING CAISSON TO OCEAN CURRENTS</title>
      <link>https://trid.trb.org/View/456557</link>
      <description><![CDATA[An analysis is made of the effect of turbulence on the vortex shedding induced vibrations of very long caissons in ocean currents. It is shown that the turbulence characteristics are important for the response.  If the ratio between the typical period of the turbulent fluctuations and the time scale for growth of vortex induced vibrations falls below a certain threshold then the fatigue damage done to the system will be rapidly decreasing with increasing turbulence intensity. The effect is particularly large when the vibrational diameter is below 0.5 diameters such that the development of the vortex correlation length becomes important.  The particular behaviour is of great importance in the design of spoiler systems for long caissons.]]></description>
      <pubDate>Wed, 27 Mar 1996 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/456557</guid>
    </item>
    <item>
      <title>A METHOD FOR COMPUTATION OF INTEGRATED VORTEX INDUCED FLUID LOADING AND RESPONSE INTERACTION OF MARINE RISERS IN WAVES AND CURRENTS</title>
      <link>https://trid.trb.org/View/433224</link>
      <description><![CDATA[A new numerical method for fully integrated hydrodynamic loading and structural response interaction of a marine riser is presented.  The method is tested for a string subjected to uniform flow.  The empirical Morison's formula is replaced by a newly developed numerical technique for computation of vortex induced forces on circular cylinders subjected to an arbitrary incoming flow.  These forces are computed by the Visflo program which is for this purpose integrated as a subroutine to the nonlinear finite element structural analysis program system Fenris.  Visflo is based on operator splitting, random walk and the vortex-in-cell method, where the vorticity is modelled by a large number of discrete vortices.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/433224</guid>
    </item>
    <item>
      <title>DEVELOPMENT OF FLOW STRUCTURES IN THE LEE OF AN INCLINED BODY OF REVOLUTION</title>
      <link>https://trid.trb.org/View/433947</link>
      <description><![CDATA[Laser-induced fluorescence has been utilised for visualising the flow structures behind an inclined body of revolution in a large towing tank. The observations have focused on the effects of the incidence angle and the Reynolds number on the axial development of the large-scale structures within the separated region, as well as the location of boundary-layer separation and reattachment. At low angles of incidence and low Reynolds numbers the flow is symmetric, containing two large centres (foci) of coalescing stream surfaces as well as several secondary structures. The transition to an asymmetric flow is observed to begin first in the downstream sections with the gradual detachment of the left primary sector and an inward motion of the right-hand centre. While detaching, the primary left structure becomes elongated as the stream surfaces break and coalesce into two distinct centres. The resulting two foci start interacting further downstream and eventually recombine. When the left centre of coalescence is completely detached, an additional centre forms in its place and the right-hand structure starts lifting away from the surface. Evidence of asymmetry very close to the tip of the model at 45 degree inclination is also provided. A series of qualitative drawings of the flow topology is provided. They follow the evolution of the flow structures in the lee of the model.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/433947</guid>
    </item>
    <item>
      <title>A FULL-SCALE EXPERIMENTAL STUDY OF THE EFFECT OF SHEAR CURRENT ON THE VORTEX-INDUCED VIBRATION AND QUASI-STATIC CONFIGURATION OF A LONG TOW CABLE</title>
      <link>https://trid.trb.org/View/434695</link>
      <description><![CDATA[The analysis of data of a unique experiment on the quasi-statics and vortex-induced dynamic of a long vertical tow cable. The measured steady-state configuration of the cable was used to calculate the cable's average drag coefficient which was 2.2 plus or minus 0.24. It was observed during the sea trials that the vortex-induced motion of the cable was modulated by a beat due to the presence of a shear current. This is confirmed here by spectral and time domain analysis of the acceleration records. The modulated amplitude caused the RMS motion of the cable to be lower than that in a uniform flow. The modulation phenomenon that is caused by the presence of a shear current thus accounts for the lower drag amplification that is observed here an has been reported elsewhere by others. The RMS motion of the cable decreases with depth which indicates that the drag coefficient of the cable also decreases with depth.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/434695</guid>
    </item>
    <item>
      <title>COMPUTATION OF VORTEX INDUCED VIBRATION AND THE EFFECT OF CORRELATION ON CIRCULAR CYLINDERS IN OSCILLATORY FLOW</title>
      <link>https://trid.trb.org/View/434697</link>
      <description><![CDATA[A numerical method for the computation of vortex shedding induced vibration is presented. The method is a discrete vortex method based on operator splitting, random walk and vortex-in-cell techniques originally developed by Stansby and Dixon (1983) at University of Manchester. Simulation of the oscillatory flow around a flexibly mounted rigid cylinder is carried out. The results are compared with experiments (Bearman et Hall 1987). The 2-dimensional fluid loading method is then applied  by a strip theory formulation for a number of sections along the same flexibly mounted rigid cylinder. The different sections are hydrodynamically uncoupled. When the cylinder starts to oscillate, the correlation between the transverse forces for each section increases, due to the motion of the cylinder only. The effect of correlation on vibration amplitudes is shown. The method is also compared with experiments for prescribed displacement of a model riser in still water (Lyons and Patel 1987).]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/434697</guid>
    </item>
    <item>
      <title>ON THE DAMPING OF AND FORCES ON A CURRENT INDUCED VIBRATING PIPELINE</title>
      <link>https://trid.trb.org/View/434698</link>
      <description><![CDATA[The influence from structural damping on the vibration amplitude of a current induced vibrating pipeline in a free span has been investigated experimentally. the gap to diameter ratio was 1.0 and the stability parameter Ks was varied in the range 1.12 - 8.8 or reduced damping in the range 0.28 - 2.22. Furthermore results of measurements of fluid forces on a current induced vibrating pipeline are presented and discussed.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/434698</guid>
    </item>
    <item>
      <title>COMPUTATION OF VORTEX INDUCED FLUID LOADING AND RESPONSE INTERACTION OF MARINE RISERS</title>
      <link>https://trid.trb.org/View/434699</link>
      <description><![CDATA[A numerical method for fully integrated hydrodynamic loading and structural response interaction of marine risers is presented. The empirical Morison's formula is replaced by a numerical technique for computation of vortex induced forces on circular cylinders subjected to an arbitrary incoming flow. The method is a discrete vortex method based on operator splitting, random walk and vortex-in-cell techniques originally developed by Stansby et al at University of Manchester. Vortex shedding induced nonsteady in-line and transverse forces on the structure are computed taking into account ambient flow from waves, current and the motion response of the compliant structure itself. The 2-dimensional fluid loading program is applied by a strip theory formulation in a number of sections along the riser, and the loads are distributed on the elements within each section. The method is tested for a marine steel riser subjected to current, waves and top-point displacement in 310m water depth. Results in form of time histories of displacements, trajectory plots, deformed shapes, power density spectra of force and response are presented. In addition a comparison with the use of the traditional Morison formula wave and current loading is shown.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/434699</guid>
    </item>
    <item>
      <title>THE SIGNIFICANCE OF WATER DEPTH ON VORTEX INDUCED VIBRATION OF MARINE RISERS</title>
      <link>https://trid.trb.org/View/442112</link>
      <description><![CDATA[A semi-empirical vortex induced vibration model which has been validated against experimental tests is the subject of this paper investigating the effects of spatial variation of wave and sheared current with increasing water depth.  A realistic tensioned riser of fixed section is extended into increasingly deep water to examine the variation of multi-modal vortex induced vibration.  Some surprises arise in respect of the occasions when vibrations become of concern.  This results from the localised nature of the regions of excitation for any mode of interest, when of course all modes which might possibly be excited are of interest.  The interactive effects of wave frequencies with vortex shedding frequencies and riser natural frequencies are shown to be important in determining the likelihood and level of vibrations.  The components of the model explain why the sometimes high levels of vibration predicted by less comprehensive models are not found in practice.  The implications for case study investigations in respect of fatigue are highlighted to show the importance of an adequately detailed range of flow conditions.  This is so since small variations can have a significant impact on the fatigue lives.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/442112</guid>
    </item>
    <item>
      <title>THE INTRODUCTION OF A SECOND PHASE AS A MEAN OF REDUCING VORTEX INDUCED VIBRATIONS</title>
      <link>https://trid.trb.org/View/442113</link>
      <description><![CDATA[Vortex shedding induced oscillations of marine structures such as, risers platform members and cold water pipes is an important fluid-structure interaction phenomenon since it can lead to structural damage and even sometimes to destructive failures.  To avoid failures of cylindrical structures in uniform or sheared flows one has to use means of suppressing or decorrelating the vortices shed behind it.  In this paper we describe a new method for reducing vortex induced vibrations of structures, by introducing a second phase (air) in the vicinity of the structure.  Laboratory experiments were carried out in 1 m deep water flume for three current speeds (u) of 0.25 m/s, 0.45 m/s and 0.8 m/s.  The air was released from manifolds attached to the structure.  The amplitude of vibrations and the forces on the structure were measured.  It was found that the amplitude of vibration was reduced by 82% when air was released at 0.5L and 0.4L (L being the cylinder length) simultaneously.  Furthermore, the mean drag force on the structure is reduced by 13% as compared to a bare cylinder.  A semi-empirical equation relating the amplitude reduction to the air flow required has been derived.]]></description>
      <pubDate>Mon, 14 Aug 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/442113</guid>
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