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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>Numerical Analysis and Structural Optimization of a Jet Pig Using a Rifling Structure</title>
      <link>https://trid.trb.org/View/2587129</link>
      <description><![CDATA[Since pigging technology is commonly used to reduce blockage or clogging during the pipeline transportation process, jet pig optimization is essential. This paper proposed a method for incorporating a rifling structure into the inner jet hole wall of a jet pig. Two types of jet pigs with differing jet hole configurations were created using modeling software, one with rifling and one without. The computational fluid dynamics (CFD) method was utilized for the analysis of the flow distribution changes in crude oil pipeline pigs. The contour maps and change curves of the fluid velocity, pressure, and turbulent kinetic energy (TKE) of the two types of pigs were obtained at different bypass fractions and inlet flow velocities. The results demonstrate that a constant inlet fluid velocity and a higher bypass fraction decrease the flow velocity and TKE of the pigs of two types, while the differential pressure values across the pigs decline gradually. The flow velocity, pressure difference, and TKE of the rifling pig exceed those of the nonrifling pig. When the bypass fraction is set at 3%, the rifling pig demonstrates about a 3.4% increase in exit flow velocity compared to its nonrifling pig, while the TKE at the outlet increases by over 13.5%. This indicates that using a rifling structure on the inner jet hole wall of the jet pig improves its dispersal ability.]]></description>
      <pubDate>Fri, 24 Oct 2025 16:53:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2587129</guid>
    </item>
    <item>
      <title>CFD Investigation on Leakage Mechanism of Natural Gas Pipeline: Flow Behavior and Quantity Estimation</title>
      <link>https://trid.trb.org/View/2526740</link>
      <description><![CDATA[Leakage in gas pipelines can lead to catastrophic consequences due to the highly flammable and explosive nature of natural gas. The main objective of this study is to investigate the leakage behavior and estimate the leakage quantity of natural gas pipelines, with the aim of timely detection of leakage sources, risk assessment, and ultimately reducing leakage disasters. To achieve this, multistage coupled numerical models considering transient gas flow and leakage diffusion are developed. The leakage behavior and the influencing factors are numerically investigated. Further, an optimal leakage rate calculation model is proposed based on simulated data sets. The results show that neglecting the boundary layer effect and the nonconstant distribution of the gas state leads to overestimation of the leakage rate. Additionally, the expansion of high-pressure gas flow in the leakage zone leads to the formation of a low-temperature zone nearby, which may further exacerbate the hazards of the leakage. The Mach disk formed impedes the diffusion of the leaking gas within the area zone. Leakage rates exhibit a basic linear relationship with pipeline operational pressure and a quadratic relationship with leakage diameter. Moreover, the deviation between real and ideal gas predictions for leakage rates increases linearly with pressure. The slight increase in leakage rate with increasing pipeline diameter is attributed to the greater density at the leak, while wall thickness and gas flow velocity within the pipeline minimally impact leakage rates. The proposed leakage model demonstrates accurate predictions across a wide range of pressures and diameters.]]></description>
      <pubDate>Tue, 22 Apr 2025 15:51:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2526740</guid>
    </item>
    <item>
      <title>Application of Electrical Analogies for Simultaneous Modeling and Simulation of Gas Transmission Pipelines and Station Turbo Compressors</title>
      <link>https://trid.trb.org/View/2526793</link>
      <description><![CDATA[Gas flow modeling and simulation are essential for identifying and managing gas transmission networks, particularly when pipelines and turbo compressors are involved. This paper presents a methodological approach for simultaneous modeling of the gas transmission pipelines and station turbo compressors using an electrical analogy. For this purpose, the electrical analogy is initially applied to form electric circuits representing gas flow in pipelines. In this study, three electrical structures are proposed for the pipeline modeling: one for the steady state and two for the transient state. The idea of two transient structures is proposed in this study to use two different electric circuits for various boundary conditions usually given for the main and demand branch lines. In addition, electric elements are incorporated to model the turbo compressor and determine its fuel consumption. Using the methodology proposed in this study, the pressure and temperature drop along the pipeline, the performance and fuel consumption of the turbo compressors, the system settling time during flow rate changes, the impact of the demand branch lines on the gas flow rate of the main pipeline, and the influence of the demand on the line pack of the branches can be evaluated. The proposed methodology is evaluated using experimental data from a real gas transmission line with industrial compressors. Finally, the Iran Gas Trunkline is used as a case study to simulate gas flow in both steady and transient states by introducing three scenarios. The results obtained from the simulation of the case study demonstrate that the proposed approach is effective for simultaneous observation of the turbo compressor performance and gas behavior at any point along the main and branch pipelines.]]></description>
      <pubDate>Tue, 22 Apr 2025 15:51:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2526793</guid>
    </item>
    <item>
      <title>Research on Transient Analysis Method for the Thermal-Fluid-Mechanical Coupling of Steel Pipelines under Natural Gas Jet Flame</title>
      <link>https://trid.trb.org/View/2526336</link>
      <description><![CDATA[The safe operation of parallel oil and gas pipelines has become a key research focus. Jet flame accidents resulting from natural gas pipeline leakages may lead to the adjacent pipelines’ failure. Therefore, it is imperative to investigate the thermal-mechanical failure of steel pipelines under natural gas jet flame, thereby determining the appropriate parallel pipeline spacing. In this paper, a thermal-fluid-mechanical coupling numerical model is established to analyze the jet flame combustion characteristics and pipe thermal-mechanical response condition. Then, the turbulence model, methane/air non-premixed combustion model, and radiation model are determined by comparing the simulation and experimental results of flame morphology, flame temperature, and heat flux. Combining the simulation method and thermal-mechanical failure criteria, a parallel spacing design method is developed. The results indicate that based on the 56-step reaction mechanism + realizable k-ε turbulence model + EDC combustion model + P1 radiation model, the average error of flame temperature, flame heat flux, pipeline temperature, and pipeline stress is 6.4%, 7.0%, 6.9%, and 8.5%, respectively, all of which meet the accuracy requirements of 10%. As the flow velocity of the pipeline decreases, valve chamber spacing and operating pressure increase, leading to a gradual increment in parallel spacing. The parallel spacing design method can prevent adjacent pipeline failure under natural gas jet flame.]]></description>
      <pubDate>Tue, 22 Apr 2025 15:51:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/2526336</guid>
    </item>
    <item>
      <title>Flow-rate Characteristics of Lubricating Oil Flow Around Discharge Hole in Rotating Shaft</title>
      <link>https://trid.trb.org/View/2505965</link>
      <description><![CDATA[Stable supply of oil for lubrication and cooling into drive units has become an important issue. The author focused on the shafts of transmissions installed in automobiles and applied the technology of current automatic transmissions. In this study, the behavior of oil lubricating a pipe simulating a shaft rotating at high speed in a multiphase state dominated by centrifugal and agitation forces was evaluated through experiments. The pipe geometry was varied, and the oil discharge behavior and discharge flow rate ratio were evaluated. The discharge velocity of lubricant in the pipe and the discharge behavior of oil from the discharge hole with changes in pipe velocity were evaluated in three patterns, and their correlations were evaluated.]]></description>
      <pubDate>Tue, 25 Mar 2025 16:57:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/2505965</guid>
    </item>
    <item>
      <title>Dynamics and Speed Control of Instrumented Pipeline Inspection Gauge in Gas Pipelines</title>
      <link>https://trid.trb.org/View/2516964</link>
      <description><![CDATA[Instrumented pipeline inspection gauges (IPIGs) are used to carry out in-line inspection of the pipelines transporting petroleum cargo. The inspection of the pipelines carrying high-speed gas needs the speed of the tool to be maintained within a specified band to produce an optimum result. It can only be achieved by introducing an effective bypass vane with a motor controller in the tool commonly known as the speed control mechanism. The mechanism controls the tool speed at a desired set value without affecting the throughput. The reported information on the effect of flow transients on the motion of the tool inside the pipelines and its control is limited in the open domain. The challenge lies in the effective design of the speed control mechanism for an IPIG tool to address the transients envisaged during the motion of the tool inside the pipeline. A computational fluid dynamics (CFD) code, based on the method of characteristics, and a control algorithm have been developed to numerically simulate the IPIG motion with a set of actual gas pipeline data. Transients incorporated in the analysis include a sudden increase in inlet flow rate and abrupt closing/opening of the bypass vane. Tool dynamics have also been studied at different openings of the vane angles in order to observe the steady-state behavior following an initial disturbance. The theoretical analysis of this initial transient is of considerable interest. The peak-to-peak speed fluctuation experienced by the IPIG is found to be inversely proportional to the local average speed of gas and directly proportional to the dynamic friction per unit area. The suitably scaled peak-to-peak speed fluctuation has been analytically correlated with the vane angle opening. The simulation results conform to the actual field data and achieve the desired speed control of the tool.]]></description>
      <pubDate>Tue, 25 Mar 2025 09:28:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/2516964</guid>
    </item>
    <item>
      <title>Bending Response and Design Equations for Gravity-Flow Pipe Liners Passing across Ring Fractures or Joints</title>
      <link>https://trid.trb.org/View/2408152</link>
      <description><![CDATA[Vehicle loads and differential ground movements can induce tensile strains in close-fitting polymer liners installed within gravity flow pipes, where the liner stretches across ring fractures or joints experiencing rotation (i.e., opening of the joint at the invert if the joint is moving down relative to the other ends of the pipe segments, or at the crown if the joint is moving upward compared with the other ends). A finite-element model is established and suitable pipe length and mesh size are determined. The stress and strain distributions along hoop and axial directions are then evaluated, considering factors such as inside diameter of the host pipe, liner thickness, rotation angle, liner elastic modulus, friction coefficient between the liner and host pipe, and Poisson’s ratio of the liner. After that, curve fitting is used to develop design equations for estimating stress and strain, and their performance is evaluated against the finite-element data. Finally, the potential effects of gravity and buoyancy are investigated. For small rotations, the stress is proportional to strain, and the maximum stress of the liner occurs directly at the joint, at the point where joint opening is greatest. The friction coefficient and liner thickness have a small effect on the maximum stress, so this simplifies consideration of this limit state in design. The design equation for stress provides estimates within 8.6% of those obtained from the three-dimensional finite-element analysis (with 𝑅² between 0.992 and 0.993). Subsequent evaluation of the proposed equation using strain measurements obtained from full-scale experiments is recommended.]]></description>
      <pubDate>Mon, 16 Sep 2024 09:00:38 GMT</pubDate>
      <guid>https://trid.trb.org/View/2408152</guid>
    </item>
    <item>
      <title>Nonlinear vortex-induced vibrations of slightly curved pipes conveying fluid in steady and oscillatory flows</title>
      <link>https://trid.trb.org/View/2118077</link>
      <description><![CDATA[An effective nonlinear dynamic model is developed to investigate vortex-induced vibration (VIV) characteristics of a slightly curved pipe conveying fluid in steady and oscillatory flows. Initial displacement caused by geometric imperfection of the slightly curved pipe is considered. Interaction between the pipe and external flow is evaluated by the van der Pol equation. Based on Hamilton's principle and the Galerkin method, the nonlinear equations of motion of the pipe system taking into account the fluid-structure interaction are established, and solved by the fourth-order Runge-Kutta method. Typical vibration features in oscillatory flows such as build-up-lock-in-die-out cycle are studied and compared with the existing experimental results to validate the accuracy of the present model. The influences of some parameters on the VIV responses of the slightly curved pipe are examined and discussed. It is found that for steady external flow, there are obvious lock-in regions for the first three mode resonances of cross-flow vibration while the displacement amplitudes of in-line vibration increase monotonically with the increase of the reduced external fluid velocity. For oscillatory external flow, the VIV dynamical behaviors are more complicated and the lock-in regions are influenced by more factors, which are distinctly different from those of the steady flow.]]></description>
      <pubDate>Wed, 22 Feb 2023 09:53:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2118077</guid>
    </item>
    <item>
      <title>Aero-Acoustic Source Terms from Large-Eddy Simulation in Turbulent Pipe Flow</title>
      <link>https://trid.trb.org/View/2004641</link>
      <description><![CDATA[In the acoustic design of flow guiding components, novel simulation concepts for predicting relevant sound sources in the early design state become increasingly important. This requires accurate numerical methods to describe the involved phenomena. The present study computationally investigates the flow-induced aeroacoustic sound sources, generated in turbulent pipe flow. The analysis follows a hybrid approach, where the acoustic sound field is predicted separately from the underlying turbulent flow field, supplied with acoustic source terms from an incompressible flow simulation of the considered configuration in the limit of low Mach number. Source terms for use as input into different acoustic wave equations, the Lighthill wave equation, the vortex sound theory, and the Perturbed Convective Wave Equation (PCWE) are computed performing incompressible Direct Numerical Simulations (DNS) and Large-Eddy Simulations (LES) of fully developed pipe flow. The predictions for the different source terms are analyzed in physical and spectral space. The comparison of the LES results against the corresponding highly resolved DNS data particularly highlights the marked effect of the applied spatial resolution as well as the contributions from the subgrid-scale model, met with different LES grids. The source terms for Lighthill and vortex sound theory are shown as highly different in magnitude reflecting the diffusion of the kinetic energy included in the latter. The transient and the convective component of the PCWE source term are shown to be strongly negative correlated, which significantly reduces the predicted amplitudes of the sound source at all frequencies.]]></description>
      <pubDate>Thu, 18 Aug 2022 15:06:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/2004641</guid>
    </item>
    <item>
      <title>Correction Factor on Dynamic Force in a Marsh Funnel Test for Tunneling</title>
      <link>https://trid.trb.org/View/1990744</link>
      <description><![CDATA[This paper presents an improvement on a previous model for predicting the Marsh funnel (MF) test that is used in slurry shield tunneling for evaluating the rheological properties of bentonite slurries. The improvement focuses on the prediction of the dynamic part for fluids with small MF times. The velocity profile of the Herschel–Bulkley fluid in a laminar pipe flow condition is first investigated and a correction factor is introduced in the improved model. Comparisons of results from experiments and calculations with the previous model confirm the improved performance over the existing model. The rheological parameters obtained from the improved model show good resemblance to those obtained from a laboratory viscometer. The work also provides a reference to similar applications such as fluid transportation through pipelines where dynamic pressure dominates and therefore should be correctly predicted considering its velocity profile in a laminar condition.]]></description>
      <pubDate>Fri, 29 Jul 2022 09:21:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/1990744</guid>
    </item>
    <item>
      <title>Computational Investigation of Concrete Pipe Flow: Critical Review</title>
      <link>https://trid.trb.org/View/1985080</link>
      <description><![CDATA[The prediction of concrete pumpability is of particular interest to properly design pumping circuits and select suitable pumps for successful processing of concrete. A critical review of empirical, analytical, and numerical models is carried out to predict concrete pumpability as a function of pipeline geometry, rheological properties of the bulk concrete, and the characteristics of the lubrication layer. The main mechanisms leading to the formation of the lubrication layer, including the wall effect, Reynolds dilatancy, and shear-induced particle migration (SIPM), are discussed. The main phenomenological models governing SIPM are formulated in terms of spatial variations of particles interaction frequency and viscosity. In addition to the single-phase methodology, new computational approaches on SIPM in pipe flow of solid-liquid suspensions are discussed. The coupled computational fluid dynamics-discrete element method (CFD-DEM) and smoothed-particle hydrodynamics (SPH) methods are recommended as the most precise and realistic approaches to simulate concrete pipe flow compared to the DEM and single-phase modelings.]]></description>
      <pubDate>Mon, 18 Jul 2022 11:25:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/1985080</guid>
    </item>
    <item>
      <title>Numerical study on the pipe flow characteristics of grouting repairing pastes used in slab track</title>
      <link>https://trid.trb.org/View/1901790</link>
      <description><![CDATA[In this study, the pipe flow characteristics of the grouting repairing pastes (GRPs) used in slab track were investigated based on three-dimensional flowing models taking into account the hydration effects. Firstly, the rheological properties of GRPs at different hydration times were measured and fitted to obtain key rheological parameters of GRPs. Then the flowing models of GRPs in pipes were established based on these rheological parameters and were verified by comparing with theoretical values. Finally, the effects of pressure gradients, pipe diameters and cement hydration on the flow characteristics of GRPs were systematically studied in terms of four indices including plug diameter, plug velocity, average velocity and the velocity ratio. Results show that the increases of pipe diameters and pressure gradients both lead to the growth of flow velocity, causing an inhomogeneity flow of GRPs in pipes. Yield stress of GRPs has the greatest influence on the flow indices. Consistency index contributes more to plug velocity and average velocity while fluid behavior index dominates the velocity ratio. To achieve a homogeneous flow at high flow rate, it is recommended to prepare a grouting repair material with moderate yield stress and low consistency index and fluid behavior index. Moreover, cement hydration causes noticeable decreases of plug velocity and average velocity under the coupling effects of rheological parameters, which may lead to the setting of GRPs near pipe wall and eventually to the occurrence of pipe blockage during transportation. In order to satisfy efficient repairing in short skylight period, it is suggested to adopt a special grouting repair material featured with slow hydration during grouting but rapid hardening after filling in the debonding area.]]></description>
      <pubDate>Tue, 01 Feb 2022 10:56:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/1901790</guid>
    </item>
    <item>
      <title>Research on bypass pigging in offshore riser system to mitigate severe slugging</title>
      <link>https://trid.trb.org/View/1905985</link>
      <description><![CDATA[During pigging operations in offshore pipelines, severe slugging can block the pig or cause sudden velocity changes. Therefore, this paper proposed a method involving bypass pigs to mitigate the influence of severe slugging on the pigging process. The impact of different inlet mass flow rates and pig bypass fractions on the characteristic parameters, such as the pressure in the riser bottom, pig velocity, and liquid-phase distribution patterns, were analyzed by combining OLGA and CFD simulations. Furthermore, the accuracy of the simulations was verified by the comparisons of OLGA and CFD, as well as the transient indoor experiments. The results show that the bypass pig significantly reduces pressure fluctuations in the riser bottom and pig velocity in severe slugging conditions, compared with the conventional pig. Consequently, the bypass pig dissipates downstream liquid slugs, reducing the mass flow rate and liquid holdup in the riser outlet. In addition, an increase in bypass fraction reduces the pressure fluctuations in the riser bottom and pig velocity, increases the ability to dissipate the downstream liquid slug, and decreases the mass flow rate and liquid holdup in the riser outlet. Increasing the inlet mass flow rate improves the ability to dissipate the downstream liquid slug. However, the inlet mass flow rate has a lower mitigation effect on severe slugging than the bypass fraction.]]></description>
      <pubDate>Wed, 26 Jan 2022 14:17:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/1905985</guid>
    </item>
    <item>
      <title>An investigation on vortex-induced vibration of a flexible riser transporting severe slugging</title>
      <link>https://trid.trb.org/View/1905984</link>
      <description><![CDATA[An investigation on the dynamic characteristics of a flexible riser due to the coupling effects of Vortex-Induced Vibration (VIV) and severe slugging is performed in this paper. Firstly, a 2D Computational Fluid Dynamics (CFD) model is developed for capturing the dynamic characteristics of severe slugging. Based on the mass and velocity of internal fluid from the CFD analysis, a classical van der Pol oscillator is employed to simulate the dynamic characteristics of the effect of VIV coupled with severe slugging. The governing equation of the riser with internal flow is discretized by the finite difference method and it is then solved by the Runge-Kutta method. The results show that the effect of severe slugging exhibits quite distinguished dynamics owing to the intermittent feature both in in-line (IL) and cross-flow (CF) directions. The VIV characteristics of the riser with severe slugging, such as frequencies, dominant modes, and root mean square (RMS) displacements, are substantially different from those of the riser without internal flow. In addition, severe slugging may trigger new mode responses of the riser and a multi-frequency vibration phenomenon in IL and CF directions due to severe slugging is observed.]]></description>
      <pubDate>Wed, 26 Jan 2022 14:17:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/1905984</guid>
    </item>
    <item>
      <title>Effects of Viscosity on Pumping Concrete Behavior Using Computational Fluid Dynamics Method</title>
      <link>https://trid.trb.org/View/1854302</link>
      <description><![CDATA[This paper aims to find the effects of viscosity on concrete behavior in pipelines. Concrete was prepared according to ACI 304.2R-96. Experiments were conducted for measuring its workability by means of slump test. Fluidity and rheology measurements of fresh mortar were investigated. The concrete behavior in pipes was directly investigated using computational fluid dynamics (CFD) simulation, which is based on the Eulerian approach and the dense discrete phase model (DDPM). Concrete behavior including flow profiles, aggregate distributions, and migration was analyzed and discussed. It was observed that the flow characteristic varies from shear flow to plug flow with increased viscosity, and the aggregate distribution along the central axis is more homogeneous. Aggregate radial migration is more pronounced with increased shearing time, decreased viscosity, and enlarged size of aggregates. It was also found that concrete between 12 and 22 Pa·s (1.74 × 10–3 and 3.19 × 10–3 psi·s) is more suitable for pumping.]]></description>
      <pubDate>Wed, 30 Jun 2021 12:01:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/1854302</guid>
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