Simplified Hydrodynamic Design Procedure of a Submerged Floating Tube Bridge Across the Digernessund of Norway

2017 ◽  
Author(s):  
Xu Xiang ◽  
Arianna Minoretti ◽  
Mathias Egeland Eidem ◽  
Kjell Håvard Belsvik ◽  
Tale Egeberg Aasland ◽  
...  
Keyword(s):  
Cross Sections ◽  
Present Model ◽  
Design Procedure ◽  
Analysis Procedure ◽  
Hydrodynamic Coefficients ◽  
Bending Moments ◽  
Vortex Induced Vibrations ◽  
Simplified Method ◽  
Hydrodynamics Coefficients ◽  
The Given

The paper will look into the hydrodynamic loads and responses on the proposed Submerged Floating Tube Bridge (SFTB) through the Digernessund by the Norwegian Public Roads Administration (Statens vegvesen, NPRA). The aim is to show how different hydrodynamics aspects during the prelimiary design can be simply addressed under the given environmental conditions. Different SFTB systems are introduced as the first step. A simplified method based on modal analysis is introduced and implemented for evaluation of the motions and stress, bending moments along the bridge. Firstly, a 2D Boundary Element Method (BEM) solver is developed and verified, which is further used for solving the hydrodynamics coefficients of different bridge cross sections. The 3D hydrodynamic coefficients of pontoons are solved by the commercial software AQWA. The analysis procedure of the simplified method for the global SFTB responses is presented. The Eigen periods of the Bjørnefjord SFTB is re-calculated by the present model as a first validation of the implementation. The loads and responses of the bridge under given wave conditions are then estimated. The evaluation of the possibility of vortex induced vibrations of the current SFTB design is given.

scholarly journals Low Energy Antikaon-nucleon/nuclei interaction studies by AMADEUS

2019 ◽  
Vol 199 ◽  
pp. 01014
Author(s):  
K. Piscicchia ◽  
M. Bazzi ◽  
G. Belloti ◽  
A. M. Bragadireanu ◽  
D. Bosnar ◽  
...  
Keyword(s):  
Cross Sections ◽  
Transition Amplitude ◽  
Nuclear Interaction ◽  
Branching Ratios ◽  
Analysis Procedure ◽  
Low Energy ◽  
Carbon Target ◽  
Pure Carbon ◽  
Nuclear Targets ◽  
Mass Spectroscopic Study

The AMADEUS experiment at the DAΦNE collider of LNF-INFN deals with the investigation of the at-rest, or low-momentum, K− interactions in light nuclear targets, with the aim to constrain the low energy QCD models in the strangeness sector. The 0 step of the experiment consisted in the reanalysis of the 2004/2005 KLOE data, exploiting K− absorptions in H, 4He, 9Be and 12C, leading to the first invariant mass spectroscopic study with very low momentum (about 100 MeV) in-flight K− captures. With AMADEUS step 1 a dedicated pure Carbon target was implemented in the central region of the KLOE detector, providing a high statistic sample of pure at-rest K− nuclear interaction. The first measurement of the non-resonant transition amplitude $\left| {{A_{{K^ - }n \to \Lambda {\pi ^ - }}}} \right|$ at $\sqrt s = 33\,MeV$ below the K̄N threshold is presented, in relation with the Λ(1405) properties studies. The analysis procedure adopted in the serarch for K− multi-nucleon absorption cross sections and Branching Ratios will be also described.

scholarly journals PECULIARITIES OF MODELING OF STRESS-STRAIN STATE OF PIPELINES THROUGH WHICH GAS-LIQUID MIXTURES WITH AGGRESSIVE COMPONENTS ARE TRANSPORTED

2019 ◽  
pp. 128-135
Author(s):  
A. P. Oliinyk ◽  
B. S. Nezamay ◽  
L. I. Feshanych
Keyword(s):  
Internal Pressure ◽  
Cross Sections ◽  
Strain State ◽  
Smoothing Splines ◽  
Liquid Mixtures ◽  
Equilibrium Equations ◽  
Stress Strain ◽  
Stress Strain State ◽  
Current State ◽  
The Given

The task of estimating the stress-strain state of pipelines through which gas-liquid mixtures with aggressive components are transported is considered, the purpose, object and object of research are established. The analysis of the current state of scientific and technical researches on the given subject is carried out, the circle of unresolved problems is revealed. The combined effect on the pipelines through which gas-liquid mixtures with aggressive components are transported stress – strained state change  is estimated by two models - the model for determining the change of the stress-strain state of the pipeline by data on the surface points certain set displacement   taking into account the quasi-stationarity of the process. The device uses interpolation smoothing splines and methods of differential geometry, 6 components of strain and stress tensors are determined. In order to substantiate the method of estimation of annular stresses at the wear of the pipeline walls due to the action of the aggressive components of the transported mixtures, systems of equilibrium equations for pipeline sections and for quasi-rectilinear sections with altered cross-section configuration have been derived. Boundaryt conditions for equilibrium equations are established. Calculation formulas for estimation of annular stresses arising under the action of internal pressure for sections with shape defects caused by the action of aggressive components are established. The results of calculations that allow to quantify the change of the most significant ring stresses arising in the pipeline material under the action of internal pressure in the pipeline cross sections, which were exposed to the aggressive components, are presented. It is assumed that the deformed sections are little different from the shape of the circle.

Reducing Damage to Low-Volume Roads by Using Trucks with Reduced Tire Pressures

1997 ◽  
Vol 1589 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Maureen A. Kestler ◽  
Richard L. Berg ◽  
Thomas L. Moore
Keyword(s):  
Cross Sections ◽  
Design Procedure ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Tire Pressure ◽  
Low Volume Roads ◽  
Minimal Damage ◽  
Allowable Load ◽  
Low Volume ◽  
Pavement Damage

Heavy-volume highways in seasonal frost areas are designed to resist the effects of spring thaw. However, timber access roads, county roads, and other low-volume roads with thin bituminous surfaces can be quite susceptible to pavement damage during midwinter- and spring-thaw periods. To reduce damage to low-volume roads, towns, cities, and states typically either post reductions in allowable load or completely prohibit hauling during damage-susceptible periods. Associated economic impact can be significant. To evaluate the effects of tire pressure on cumulative road damage, a mechanistic pavement design procedure developed by the U.S. Army Corps of Engineers for use in seasonal frost areas was used on a matrix of tire pressures, low-volume pavement cross sections, and environmental conditions. A series of computer simulations showed ( a) trucks operating with conventional tire pressures can cause excessive damage, particularly in the form of cracking, to low-volume roads with thin bituminous surfaces during relatively short thaw periods; ( b) pavement damage could be reduced substantially by restricting hauling to trucks operating with reduced tire pressures; and ( c) there are “threshold” tire pressures under which only minimal damage occurs, even during critical spring thaw. These results could influence guidelines for hauling restrictions and, in turn, associated economics.

scholarly journals Premature destruction of two-span RC beams exposed to high temperature caused by a redistribution of shear forces

2016 ◽  
Vol 23 (4) ◽  
pp. 431-439 ◽  
Author(s):  
Robert KOWALSKI ◽  
Michał GŁOWACKI ◽  
Marian ABRAMOWICZ
Keyword(s):  
High Temperature ◽  
Cross Sections ◽  
Bending Moment ◽  
Middle Part ◽  
Transverse Reinforcement ◽  
Shear Load ◽  
Bending Moments ◽  
Rc Beams ◽  
Shear Forces ◽  
Load Bearing Capacity

When multi-span RC elements are exposed to fire one usually observes a yielding of span cross-sections while a safety reserve of support cross-sections is still significant. Due to this phenomenon a redistribution of bending moments occurs and the values of sagging moment in span cross-sections decrease while the values of hogging moment in support cross-sections increase. This paper shows the results of tests conducted on two-span RC beams in a situation when only one span has been exposed to high temperature from the bottom. The beams were 12×16 cm in their cross-section. The length of the span was 165 cm. The load has been applied by two forces put on each span. The beams were made of C25/30 concrete with siliceous aggregate. As a result of significant stiffness decrease of the heated span, redistribution of shear forces and bending moment occurs. Due to this redistribution the tested beams were prematurely damaged due to exhaust of the shear load bearing capacity in the middle part of the beam span where there was no transverse reinforcement.

Reynolds Number Effects on Hydrodynamic Coefficients for Pure In-Line and Pure Cross-Flow Forced Vortex Induced Vibrations

2009 ◽  
Author(s):  
Jamison L. Szwalek ◽  
Carl M. Larsen
Keyword(s):  
Reynolds Number ◽  
Prediction Models ◽  
Current Knowledge ◽  
Cross Flow ◽  
Reynolds Numbers ◽  
Added Mass ◽  
Hydrodynamic Coefficients ◽  
Vortex Induced Vibrations ◽  
Reynolds Number Effects ◽  
Sinusoidal Oscillations

In-line vibrations have been noted to have an important contribution to the fatigue of free spanning pipelines. Still, in-line contributions are not usually accounted for in current VIV prediction models. The present study seeks to broaden the current knowledge regarding in-line vibrations by expanding the work of Aronsen (2007) to include possible Reynolds number effects on pure in-line forced, sinusoidal oscillations for four Reynolds numbers ranging from 9,000 to 36,200. Similar tests were performed for pure cross-flow forced motion as well, mostly to confirm findings from previous research. When experimental uncertainties are accounted for, there appears to be little dependence on Reynolds number for all three hydrodynamic coefficients considered: the force in phase with velocity, the force in phase with acceleration, and the mean drag coefficient. However, trends can still be observed for the in-line added mass in the first instability region and for the transition between the two instability regions for in-line oscillations, and also between the low and high cross-flow added mass regimes. For Re = 9,000, the hydrodynamic coefficients do not appear to be stable and can be regarded as highly Reynolds number dependent.

scholarly journals Development of the computerized decision-making support system for the prevention and revealing of dangerous zones of flooding

2019 ◽  
Vol 97 ◽  
pp. 05040 ◽  
Author(s):  
Farrukh Shaazizov ◽  
Bakhtiyar Uralov ◽  
Elyor Shukurov ◽  
Aydar Nasrulin
Keyword(s):  
Cross Sections ◽  
Calculation Method ◽  
Visual Inspection ◽  
Wave Speed ◽  
Emergency Situation ◽  
Technical Condition ◽  
The Common ◽  
The Given ◽  
Modern Condition ◽  
Partial Destruction

In considered article the results are presented of the carried out researches on high-mountainous lakes of the Tashkent area. Visual inspection of a modern condition of natural dams of considered high-mountainous lakes of the Tashkent oblast is carried out. On the basis of the analysis of visual inspection it is possible to note, that the common technical condition of natural dams of the submitted high-mountainous lakes safe and does not represent danger to downstream situated territories. It was carried out the modeling of occurrence of emergency situation on high-mountainous lakes of the Tashkent oblast in case of full or partial destruction of natural dams. By an available calculation method of flooding waves are determined its key parameters, height of a wave, speed of distribution of a wave of break on the certain distances and reaching time the given wave up to the certain distances. On the basis of calculation method have been calculated and put on cross-sections of the rivers Pskem and Kocy zones of possible flooding in full and partial destruction of dams of high-mountainous lakes. Results of the carried out calculations have been put on the digital map, created on platform ArcView 3.2a.

Use of Centrifuge and Numerical Modeling in Design of Pier 400 at the Port of Los Angeles

1997 ◽  
Vol 1582 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Kanthasamy K. Muraleetharan ◽  
Kandiah Arulmoli ◽  
Richard C. Wittkop ◽  
John E. Foxworthy
Keyword(s):  
Los Angeles ◽  
Seismic Design ◽  
Cross Sections ◽  
Model Tests ◽  
Analysis Procedure ◽  
Centrifuge Model ◽  
Port Of Los Angeles ◽  
Centrifuge Models ◽  
Fully Coupled ◽  
Centrifuge Model Tests

Port of Los Angeles (POLA) is involved in the creation of 235 ha (580 acres) of new land called Pier 400 by dredging and landfilling behind rock dikes. Because of the complicated nature of the project, POLA chose a fully coupled, elastoplastic, dynamic finite-element code called DYSAC2 as part of the seismic design of Pier 400. The predictions made by DYSAC2 were first validated using dynamic centrifuge model tests. Centrifuge model tests consisting of gravel dikes retaining sand backfills overlying stratified foundation soils also provided insight into the expected deformation mechanisms of Pier 400 cross sections. Centrifuge models indicated that the dikes will move more or less as a rigid block with most of the lateral deformations being concentrated in the foundation soils. These observations were confirmed by analyses of centrifuge models and Pier 400 cross sections using DYSAC2. Because of the rigid body movement of the dikes, a hybrid analysis procedure, between simplified Newmark’s method and the DYSAC2 analysis procedure in sophistication, was developed for the lateral deformation calculations of the Pier 400 cross sections. The hybrid method is similar to Newmark’s method, but yield acceleration values are calculated using average excess pore pressures predicted by DYSAC2 in the foundation soils and the landfill. In essence, the Pier 400 design team and POLA used results from sophisticated fully coupled procedures and centrifuge model tests together with traditional embankment analysis techniques and engineering judgment to produce a viable and safe seismic design of Pier 400 dikes and landfill.

Improved In-Line Vortex-Induced Vibrations Prediction for Combined In-Line and Cross-Flow Vortex-Induced Vibrations Responses

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Decao Yin ◽  
Elizabeth Passano ◽  
Carl M. Larsen
Keyword(s):  
Cross Flow ◽  
Hydrodynamic Coefficients ◽  
Marine Structures ◽  
Flexible Pipe ◽  
Flexible Beams ◽  
Forced Motion ◽  
Pipe Model ◽  
Vortex Induced Vibrations ◽  
Flow Vortex ◽  
Semi Empirical

Slender marine structures are subjected to ocean currents, which can cause vortex-induced vibrations (VIV). Accumulated damage due to VIV can shorten the fatigue life of marine structures, so it needs to be considered in the design and operation phase. Semi-empirical VIV prediction tools are based on hydrodynamic coefficients. The hydrodynamic coefficients can either be calculated from experiments on flexible beams by using inverse analysis or theoretical methods, or obtained from forced motion experiments on a circular cylinder. Most of the forced motion experiments apply harmonic motions in either in-line (IL) or crossflow (CF) direction. Combined IL and CF forced motion experiments are also reported. However, measured motions from flexible pipe VIV tests contain higher order harmonic components, which have not yet been extensively studied. This paper presents results from conventional forced motion VIV experiments, but using measured motions taken from a flexible pipe undergoing VIV. The IL excitation coefficients were used by semi-empirical VIV prediction software vivana to perform combined IL and CF VIV calculation. The key IL results are compared with Norwegian Deepwater Programme (NDP) flexible pipe model test results. By using present IL excitation coefficients, the prediction of IL responses for combined IL and CF VIV responses is improved.

scholarly journals Discrete Velocity Boltzmann Model for Quasi-Incompressible Hydrodynamics

Mathematics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 993
Author(s):  
Oleg Ilyin
Keyword(s):  
Cross Sections ◽  
Lattice Boltzmann ◽  
Present Model ◽  
Test Problems ◽  
Hydrodynamic Equations ◽  
Interacting Particles ◽  
Closed Expression ◽  
Discrete Velocity ◽  
H Theorem ◽  
Boltzmann Model

In this paper, we consider the development of the two-dimensional discrete velocity Boltzmann model on a nine-velocity lattice. Compared to the conventional lattice Boltzmann approach for the present model, the collision rules for the interacting particles are formulated explicitly. The collisions are tailored in such a way that mass, momentum and energy are conserved and the H-theorem is fulfilled. By applying the Chapman–Enskog expansion, we show that the model recovers quasi-incompressible hydrodynamic equations for small Mach number limit and we derive the closed expression for the viscosity, depending on the collision cross-sections. In addition, the numerical implementation of the model with the on-lattice streaming and local collision step is proposed. As test problems, the shear wave decay and Taylor–Green vortex are considered, and a comparison of the numerical simulations with the analytical solutions is presented.

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