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Numerical estimation of bank-propeller-hull interaction effect on ship manoeu-vring using CFD method

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Journal of Hydrodynamics 2017年第1期29卷 154-167页

作者： S.Kaidi H.Smaoui P.Sergent cerema-DtecEMF 60280 Margny-les-CompiegneFrance Sorbonne universites Universite de technologie de Compiegnelaboratoire Roberval60203 Compiegne cedexFrance

This paper presents a numerical investigation of ship manoeuvring under the combined effect of bank and propeller. The incompressible turbulent flow with free surface around the self-propelled hull form is simulated using a commercial CFD software （ANSYS-FLUENT）. In order to estimate the influence of the bank-propeller effect on the hydrodynamic forces acting on the ship, volume forces representing the propeller are added to Navier-Stokes equations. The numerical simulations are carried out using the equivalent of experiment conditions. The validation of the CFD model is performed by comparing the numerical results to the availa- ble experimental data. For this investigation, the impact of Ship-Bank distance and ship speed on the bank effect are tested with and without propeller. An additional parameter concerning the advance ratio of the propeller is also tested.

关键词： Viscous fluid flow simulation (CFD) bank effect bank-propeller-hull interaction hydrodynamic forces estimations,advance ratio

Two-dimensional modeling of fine sediment transport with mixed sediment and consolidation: Application to the Gironde Estuary,France

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International Journal of Sediment Research 2021年第6期36卷 736-746页

作者： Sylvain Orseau Nicolas Huybrechts Pablo Tassi Damien Pham Van Bang Fabrice Klein cerema Direction Technique Eau Mer et Fleuves Sorbonne Universités Université de Technologie de Compiégne CNRSFRE2012 RobervalCentre de Recherche Royallieu Electricité de France R&D Department Laboratoire d'Hydraulique Saint Venant (ENPC-EDF/R&D-cerema) 5. Centre Eau Terre et Environnement INRS-ETE 6. Grand Port Maritime de Bordeaux

In order to optimize ship navigation in the macrotidal Gironde Estuary, a recent project funded by the port of Bordeaux aims at better understand and forecast hydrodynamic and fine sediment transport within the estuary. In the framework of this project, a two-dimensional hydro-sedimentary model is built. The model includes hydrodynamic forcings, mixed-sediment transport, and consolidation processes. The harmonic analysis of the astronomical tides reveals a strong distortion of the tidal wave inducing the growth of overtide constituents and the non-significant effect of tide-surge interactions in annual-scale prediction. Depending on hydrological conditions, river discharge can considerably alter the model accuracy due to the migration of the turbidity maximum zone modifying the bottom *** with measurements shows the ability of the model to reproduce suspended-sediment concentrations in the central Estuary. Sensitivity of the model to sediment features has also been discussed in regard of suspended-sediment concentrations and fluid mud deposits. The model will be further coupled with ship squat predictions and a morphodynamic model.

关键词： Sediment transport Numerical modeling Mixed sediment Gironde Estuary Opentelemac

Simulation of the overtaking maneuver between two ships using the non-linear maneuvering model

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Journal of Hydrodynamics 2018年第5期30卷 791-802页

作者： Peng Du A. Ouahsine K. T. Tran p. Sergent Laboratoire Roberval UMR-CNRS 7337 Sorbonne Universites Universite de Technology de Compiegne Centre de Recherches Royallieu CS 60319 60203 Compiegne cedex France cerema-134 Rue de Beauvais CS 60039 60200 Compiegne cedex France

The overtaking maneuver of two Esso Bernicia 1.9×10^5 DWT tankers was investigated using the system-based maneuvering method. The Brix model was incorporated to account for the overtaking interactions. Forces/moment acting on the ship hulls and maneuvering motions were analyzed for both ships during the overtaking. The influences of the speed ratio and the passing distance were specially studied. Two fitting formulas for the minimum distance during the overtaking were finally established as functions of the two factors respectively. They can be used to predict the minimum distance during an overtaking maneuver under similar conditions to avoid marine accidents.

关键词： Ship-to-ship interaction maneuvering overtaking draught yaw

Replacement of alkali silicate solution with silica fume in metakaolin-based geopolymers

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International Journal of Minerals,Metallurgy and Materials 2019年第5期26卷 555-564页

作者： Ahmed Nmiri Myriam Duc Noureddine Hamdi Oumaya Yazoghli-Marzouk Ezzeddine Srasra National Center for Research in Materials Sciences Technop?le Borj Cedria (CNRSM) Department of Chemistry Faculty of Sciences of Tunis University of Tunis El-Manar French Institute of Science and Technology for Transport Development and Networks (IFSTTAR) Center for Studies and Expertise on Risks Environment Mobility and Development (CEREMA)

A metakaolin(Mk)-based geopolymer cement from Tunisian Mk mixed with different amounts of silica fume(SiO_2/Al_2O_3 molar ratio varying between 3.61 and 4.09) and sodium hydroxide(10M) and without any alkali silicate solution, is developed in this work. After the samples were cured at room temperature under air for 28 d, they were analyzed by X-ray diffraction(XRD), Fourier transform infrared(FTIR) spectroscopy, environmental scanning electron microscopy, mercury intrusion porosimetry, ^(27)Al and ^(29)Si nuclear magnetic resonance(NMR) spectroscopy, and compression testing to establish the relationship between microstructure and compressive strength. The XRD, FTIR, and ^(27)Al and ^(29)Si NMR analyses showed that the use of silica fume instead of alkali silicate solutions was feasible for manufacturing geopolymer cement. The Mk-based geopolymer with a silica fume content of 6 wt%(compared with those with 2% and 10%), corresponding to an SiO_2/Al_2O_3 molar ratio of 3.84, resulted in the highest compressive strength, which was explained on the basis of its high compactness with the smallest porosity. Silica fume improved the compressive strength by filling interstitial voids of the microstructure because of its fine particle size. In addition, an increase in the SiO_2/Al_2O_3 molar ratio, which is controlled by the addition of silica fume, to 4.09 led to a geopolymer with low compressive strength, accompanied by microstructures with high porosity. This high porosity, which is responsible for weaknesses in the specimen, is related to the amount of unreacted silica fume.

关键词： metakaolin silica fume geopolymer cement compressive strength

Effect of self-weight consolidation on a hydro-sedimentological model for the Río de la Plata estuary

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International Journal of Sediment Research 2019年第5期34卷 444-454页

作者： Pablo Santoro Mónica Fossati Pablo Tassi Nicolas Huybrechts Damien Pham Van Bang Ismael Piedra-Cueva Instituto de Mecánica de los Fluidos e Ingeniería Ambiental Facultad de Ingeniería Universidad de la República Université Paris-Est Laboratory for Hydraulics Saint-Venant (ENPC-EDF/R& D-CEREMA) Electricity of France R&D Department Sorbonne Universités Université de Technologie de Compiègne FRE UTC-CNRS 3023 Roberval Centre de Recherche Royallieu cerema Direction Technique Eau Mer et Fleuves Institut National de la Recherche Scientifique Centre-Eau Terre Environnement

The effect of the consolidation process on the morphodynamics and fine sediment dynamics of the Río de la Plata estuary is explored through a circulation-wave-sediment transport model. The consolidation model is calibrated based on settling column experimental data. Different simulations are done in order to initialize the mud layer distribution and to investigate the impact of different erosion parameter assumptions on the modeled sediment dynamics. Finally a two-year simulation is done with and without the consolidation process and realistic hydrodynamic forcings. Considering the consolidation process, the model correctly reproduces measured vertical density profiles in the Montevideo Bay access channel. The simulated suspended sediment dynamics behavior in Montevideo Bay with the consolidation process provides a more realistic deposition pattern in regard to the dredging activities.

关键词： Cohesive sediment Self-weight consolidation Morphodynamics Numerical modeling

Three-dimensional simulation of horseshoe vortex and local scour around a vertical cylinder using an unstructured finite-volume technique

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International Journal of Sediment Research 2020年第3期35卷 295-306页

作者： Wei Zhang Miguel Uh Zapata Xin Bai Damien Pham-Van-Bang Kim Dan Nguyen Laboratory for Hydraulics Saint-Venant (LHSV ENPC-EDF R&D-Cerema)University Paris-Est CONACYT Centro de Investigacion en Matematicas A.C.(CIMAT)Unidad Merida 3. Laboratory for Hydraulics and Environment (LHE)Institut National de La Recherche ScientifiqueUniversite Du Quebec

A Large Eddy Simulation model is developed to simulate the hydrodynamics and scour process around a circular *** Navier-Stokes solver is based on the projection method and a second-order unstructured finite-volume method.A sigma-coordinate system is used to obtain an accurate representation of the evolution of the sediment-water *** erosion is simulated by solving the sediment continuity equation using a mass-conservating sand-slide algorithm and a bedload transport rate,which is based on a description of physical processes(Engelund & Freds(?)e,1976).Simulations of flow around a vertical cylinder for free-slip bed,rigid bed,and live-bed cases are *** mean velocity profile and shear stress validate the accuracy of this *** vortex and lee-wake vortex shedding structure are simulated,and the results are thoroughly discussed in *** formation and the temporal development of the scour hole and other topographic bed features are successfully *** current paper reports the first known investigation of both scour evolution and coherent structure using large-eddy simulation.

关键词： Non-hydrostatic flows Horseshoe vortex Wake region Scouring Bedload transport

Development and Evolution of the Size of Polygonal Fracture Systems during Fluid-Solid Separation in Clay-Rich Deposits

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Journal of Earth Science 2018年第6期29卷 1319-1334页

作者： Teodolina Lopez Raphael Antoine JoséDarrozes Michel Rabinowicz David Baratoux CESBIO Universite de ToulouseCNES/CNRS/IRD/UPSloulousePrance International Space Science Institute(ISSI) BernSwitzerland cerema Laboratoire Regional de RouenGroupe Sciences de la TerreCS 90245F-76121 Le Grand QuevillyFrance GET Universite de ToulouseUPS/CNRS/IRD/CNESToulouseFrance Institut Fondamental d'Afrique Noire(IFAN) Cheikh Anta DioDakarSenegal

In continental and oceanic conditions, clay-rich deposits are characterised by the development of polygonal fracture systems（PFS）. PFS can increase the vertical permeability of clay-rich deposits（mean permeability ≤10-16 m2） and are pathways for fluids. On continents, the width of PFS ranges from centimeters to hundreds of meters, while in oceanic contexts they are up to a few kilometers large. These structures are linked to water-solid separation during deposition, consolidation and complete fluid squeeze of the clay horizon. During the last few decades, modeling of melt migration in partially molten plastic rocks led to rigorous quantifications of two-phase flows with a particular emphasis on 2D and 3D induced flow structures. The numerical modeling shows that the melt migrates on distances almost equal to a few times the compaction length L that depends on permeability and viscosity. Consequently, polygonal structures in partially molten plastic rocks are resulted from the melt-rock separation and their sizes are proportional to L. Applying these results to fluid-solid separation in clay-rich horizons, we show that（1） centimetric to kilometric PFS are resulted from the dramatic increase of L during compaction and（2）, this process involves agglomerates with 100 μm to 1 mm size.

关键词： compaction clay deposit agglomerates polygonal fractures desiccation cracks

Static-based early-damage detection using symbolic data analysis and unsupervised learning methods

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Frontiers of Structural and Civil Engineering 2015年第1期9卷 1-16页

作者： Joao Pedro SANTOS Christian CREMONA Andre D. ORCESI Paulo SILVEIRA Luis CALADO Department of Structures Av. Brasil 101 Lisbon 1700-066 Portugal Technical Center for Bridge Engineering CEREMA B.P. 214 Provins Cedex 77487 France Materials and Structures Department IFSTTAR University Paris-Est 14-20 Boulevard Newton Champs sur Marne Marne la Vallee Cedex2 F-77447 France Department of Civil Engineering Technical University Lisbon Avenida Rovisco Pais Lisbon 1096 Portugal

A large amount of researches and studies have been recently performed by applying statistical and machine learning techniques for vibration-based damage detection. However, the global character inherent to the limited number of modal properties issued from operational modal analysis may be not appropriate for early-damage, which has generally a local character. The present paper aims at detecting this type of damage by using static SHM data and by assuming that early-damage produces dead load redistribution. To achieve this objective a data driven strategy is proposed, consisting of the combination of advanced statistical and machine learning methods such as principal component analysis, symbolic data analysis and cluster analysis. From this analysis it was observed that, under the noise levels measured on site, the proposed strategy is able to automatically detect stiffness reduction in stay cables reaching at least 1%.

关键词： structural health monitoring early-damage detection principal component analysis symbolic data symbolic dissimilarity measures cluster analysis numerical model damage simulations

欧洲的“出行即服务”——学习借鉴赫尔辛基、维也纳和汉诺威的经验

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人民公交 2021年第2期 6-13页

作者：无王健胡敏翔管妮娜王承翔法国风险、环境、出行与规划中心(cerema) 共享出行实验室

出行即服务(MaaS)被看作改变人类出行服务的一种革命性工具,在特定区域可以方便地接驳各种公共交通、共享出行或私人交通的数字化服务。许多出行即服务系统都在大城市地区发展,基于智能手机的应用程序为出行者提供个性化和方便的出行服... 详细信息

出行即服务(MaaS)被看作改变人类出行服务的一种革命性工具,在特定区域可以方便地接驳各种公共交通、共享出行或私人交通的数字化服务。许多出行即服务系统都在大城市地区发展,基于智能手机的应用程序为出行者提供个性化和方便的出行服务,出行即服务这个新概念在世界各地不同城市所反应的实际情况却各有不同。

关键词：应用程序出行服务数字化服务智能手机私人交通特定区域公共交通赫尔辛基