scholarly journals Numerical Modeling of Wave Disturbances in the Process of Ship Movement Control

Algorithms ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 130 ◽  
Author(s):  
Piotr Borkowski
Keyword(s):  
Stochastic Process ◽  
Numerical Modeling ◽  
Numerical Model ◽  
Wave Spectrum ◽  
Movement Control ◽  
Angular Speed ◽  
Stabilization System ◽  
Wave Impact ◽  
Wave Disturbances ◽  
Sea Wave

The article presents a numerical model of sea wave generation as an implementation of the stochastic process with a spectrum of wave angular velocity. Based on the wave spectrum, a forming filter is determined, and its input is fed with white noise. The resulting signal added to the angular speed of a ship represents disturbances acting on the ship’s hull as a result of wave impact. The model was used for simulation tests of the influence of disturbances on the course stabilization system of the ship.

Three-dimensional numerical modeling of cohesive sediment transport and wind wave impact in a shallow oxbow lake

2008 ◽  
Vol 31 (7) ◽  
pp. 1004-1014 ◽  
Author(s):  
Xiaobo Chao ◽  
Yafei Jia ◽  
F. Douglas Shields ◽  
Sam S.Y. Wang ◽  
Charles M. Cooper
Keyword(s):  
Numerical Modeling ◽  
Sediment Transport ◽  
Wind Wave ◽  
Three Dimensional ◽  
Cohesive Sediment ◽  
Oxbow Lake ◽  
Wave Impact ◽  
Cohesive Sediment Transport

scholarly journals Dating the Irrigation System of the Samarkand Oasis: A Geoarchaeological Study

Radiocarbon ◽  
2012 ◽  
Vol 54 (1) ◽  
pp. 91-105 ◽  
Author(s):  
Luca C Malatesta ◽  
Sébastien Castelltort ◽  
Simone Mantellini ◽  
Vincenzo Picotti ◽  
Irka Hajdas ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Numerical Model ◽  
Radiocarbon Dating ◽  
Overland Flow ◽  
Irrigation System ◽  
Archaeological Sites ◽  
New Approach ◽  
Sedimentary Deposits ◽  
New Evidence ◽  
Southern Flank

The oasis of Samarkand in the Middle Zeravshan Valley (modern Uzbekistan) was a major political and economic center in ancient western Central Asia. The chronology of its irrigation system was, until now, only constrained by the quality and quantity of archaeological findings and several different hypotheses have been proposed for it. We use a new approach combining archaeological surveying, radiocarbon dating, sedimentary analysis, and the numerical modeling of a flood event to offer new evidence for, and quantitative dating of, the development of irrigation system on the southern flank of the Middle Zeravshan Valley. We analyzed 13 bones and charcoals from 3 archaeological sites and obtained new 14C ages from Afrasiab (ancient Samarkand), a dwelling damaged by flooding in the 2nd century AD (site code: SAM-174) and the fortress of Kafir Kala. We established the origin of sedimentary deposits at the sites to infer the presence of the 2 most important canals of the southern flank: the Dargom and the Yanghiaryk. Finally, we show with a numerical model of overland flow that a natural flood was unlikely to have produced the damage observed at SAM-174. The combined results of the study indicate that the canals south of Samarkand existed, and were mainly developed, in the 2nd century AD and were not connected to the main feeding canal of Afrasiab at that time.

scholarly journals Field surveys and numerical modeling of the August 2016 Typhoon Lionrock along the northeastern coast of Japan: the first typhoon making landfall in Tohoku region

2020 ◽  
Vol 105 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Mohammad Heidarzadeh ◽  
Takumu Iwamoto ◽  
Tomohiro Takagawa ◽  
Hiroshi Takagi
Keyword(s):  
Numerical Modeling ◽  
Numerical Model ◽  
Tide Gauge ◽  
Wave Runup ◽  
Field Surveys ◽  
Death Toll ◽  
Hurricane Wind ◽  
Northeastern Japan ◽  
Strong Winds ◽  
Severe Flooding

AbstractTyphoon Lionrock, also known as the national number 1610 in Japan, caused severe flooding in east Japan in August 28–31, 2016, leaving a death toll of 22. With a maximum sustained wind speed of ~ 220 km/h from the Joint Typhoon Warning Center’s best track, Lionrock was classified as a category 4 hurricane in Saffir–Simpson Hurricane Wind Scale and as a typhoon in Japan Meteorological Agency’s scale. Lionrock was among unique typhoons as it started its landfall from north of Japan. Here, we studied the characteristics of this typhoon through tide gauge data analysis, field surveys and numerical modeling. Tide gauge analysis showed that the surges generated by Lionrock were in the ranges of 15–55 cm with surge duration of 0.8–3.1 days. Our field surveys revealed that the damage to coastal communities/structures was moderate although it caused severe flooding inland. We measured a maximum coastal wave runup of 4.3 m in Iwaisaki. Such a runup was smaller than that generated by other category 4 typhoons hitting Japan in the past. Our numerical model was able to reproduce the storm surge generated by the 2016 Typhoon Lionrock. This validated numerical model can be used in the future for typhoon-hazard studies along the coast of northeastern Japan. Despite relatively small surge/wave runups in coastal areas, Lionrock’s death toll was more than that of some other category 4 typhoons. We attribute this to various primary (e.g., flooding, surges, waves, strong winds) and secondary (e.g., landslides, coastal erosions, debris flows, wind-blown debris) mechanisms and their combinations and interactions that contribute to damage/death during a typhoon event.

2-D AUTOMATIC COMPOSITION OF NODAL VALUES FROM NUMERICAL MODEL USING SCRIPT PROGRAMMING

2013 ◽  
Vol 62 (1) ◽  
Author(s):  
Rudi Heriansyah
Keyword(s):  
Finite Element ◽  
Numerical Modeling ◽  
Numerical Model ◽  
Finite Difference ◽  
Two Dimensional ◽  
Commercial Software ◽  
One Dimensional ◽  
Automatic Composition ◽  
The Individual ◽  
Individual Nodes

There are many commercial software to perform numerical modeling based on finite element (FEM) and finite difference (FDM) methods. It is often a requirement to the designer, that the values of the individual nodes in the numerical model are known. Usually, these softwares provide two methods to achieve this; firstly, by clicking directly onto the nodes of interest and secondly, by saving or exporting the whole nodal values to an external file. The former way is appropriate for models with small number of nodes, but as the number of nodes increases, it is no longer an efficient or effective way. Through the latter method, all nodal values are obtained, however the values are one-dimensional, and in some cases, only certain nodal values are required for presentation. In this paper, an algorithm for automatic composition of nodal values obtained from the second method mentioned above. The composed nodal values will be in two-dimensional form as this is the format used for uniform shaped model (square or rectangular). Since numerical softwares usually have facilities to save the data in a spreadsheet format, the proposed algorithm is implemented in this environment by using spreadsheet script programming.

Numerical Modeling of a Nonlinear MEMS Membrane

2004 ◽  
Author(s):  
Owen I. Crabtree ◽  
Sinisa Dj. Mesarovic ◽  
Ismail Demir ◽  
Robert F. Richards ◽  
David F. Bahr ◽  
...  
Keyword(s):  
Residual Stress ◽  
Numerical Modeling ◽  
Numerical Model ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Empirical Data ◽  
Geometrically Nonlinear ◽  
Mems Device ◽  
The Finite Difference Method ◽  
Stress Layer

A numerical model is developed to understand the behavior of a laminated, piezoelectric, geometrically nonlinear MEMS device. The finite difference method is chosen, along with the Newmark technique to model the static and vibrational behavior. This technique is validated by comparison to empirical data. The developed model is exercised to understand and optimize the device by studying residual stress, layer thicknesses, and electrode sizes with the goal of reduction of fundamental frequency and increase of charge output.

Experimental and Numerical Investigation of Dynamic Impact on Universal Breakaway Steel Post

2019 ◽  
Author(s):  
Javad Mehrmashhadi ◽  
Mojdeh A. Pajouh ◽  
John D. Reid
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Numerical Model ◽  
Dynamic Impact ◽  
Roadside Safety ◽  
Impact Performance ◽  
Component Testing ◽  
Long Span ◽  
Finite Element Package ◽  
The Impact

Abstract A closed guardrail system, known as “bullnose” guardrail system, was previously developed to prevent out-of-control vehicles from falling into the elephant trap. The bullnose guardrail system originally used Controlled Release Terminal (CRT) wood posts to aid in the energy absorption of the system. However, the use of CRT had several drawbacks such as grading and the need for regular inspections. Universal Breakaway Steel Post (UBSP) was then developed by the researchers at Midwest Roadside Safety Facility as a surrogate for CRT. In this study, the impact performance of UBSP on the weak-axis and strong-axis was studied through numerical modeling and component testing (bogie testing). A numerical model was developed using an advanced finite element package LS-DYNA to simulate the impact on UBSP. The numerical results were compared to experimental data. Further research on soil models was recommended. The numerical model will be used to investigate other applications for UBSP such as the Midwest Guardrail System (MGS) long span system, guardrail end terminal designs, or crash cushions.

Experimental Observations and Numerical Simulations of Wave Impact Forces on Recurved Parapets Mounted Above a Vertical Wall

2009 ◽  
Author(s):  
David Newborn ◽  
Nels Sultan ◽  
Pierre Beynet ◽  
Tim Maddux ◽  
Sungwon Shin ◽  
...  
Keyword(s):  
Numerical Model ◽  
Numerical Simulations ◽  
Shear Force ◽  
Experimental Testing ◽  
Vertical Wall ◽  
Experimental Tests ◽  
Vertical Force ◽  
Base Shear ◽  
Wave Impact ◽  
Overturning Moment

Large-scale hydraulic model tests and detail numerical model investigations were conducted on recurved wave deflecting structures to aid in the design of wave overtopping mitigation for vertical walls in shallow water. The incident wave and storm surge conditions were characteristic return period events for an offshore island on the North Slope of Alaska. During large storm events, despite depth-limited wave heights, a proposed vertical wall extension was susceptible to wave overtopping, which could potentially cause damage to equipment. Numeric calculations were conducted prior to the experimental tests and were used to establish the relative effectiveness of several recurved parapet concepts. The numerical simulations utilized the COrnell BReaking waves and Structures (COBRAS) fluid modeling program, which is a Volume-of-Fluid (VOF) model based on Reynolds Averaged Navier-Stokes equations [1] [2]. The experimental testing was conducted in the Large Wave Flume (LWF) at Oregon State University, O.H. Hinsdale Wave Research Laboratory. The experimental test directly measured the base shear force, vertical force, and overturning moment applied to the recurved parapets due to wave forcing. Wave impact pressure on the parapet and water particle velocities seaward of the wall were also measured. Results from the experimental testing include probability of exceedance curves for the base shear force, vertical force, and overturning moment for each storm condition. Qualitative comparisons between the experimental tests and the COBRAS simulations show that the numerical model provides realistic flow on and over the parapet.

FEM Analysis of Mecano-Welding Process for Manufacturing Cylinders

2013 ◽  
Vol 549 ◽  
pp. 444-451
Author(s):  
Zheng Kun Feng ◽  
Henri Champliaud
Keyword(s):  
Numerical Modeling ◽  
Numerical Model ◽  
Welding Process ◽  
Fem Analysis ◽  
Ansys Software ◽  
Process Mechanism ◽  
Design And Optimization ◽  
Implicit Solvers ◽  
Roll Bending

Cylindrical components produced by mecano-welding process are widely used in industries. The mecano-welding process consists of a roll bending sub-process which can produce non-closed cylinders and a welding process which can seam gaps. This paper proposes a numerical model to simulate the process and to get better understanding of the process mechanism. Explicit and implicit solvers are applied to the numerical modeling by using LS-DYNA and ANSYS software. The numerical model can provide a useful tool for design and optimization of the mecano-welding process.

Numerical Modeling of the Oil Spill Trajectory and Real-Time Tracking Using Intelligent Swarm Robots

2013 ◽  
Vol 446-447 ◽  
pp. 1261-1265 ◽  
Author(s):  
Mohsen Pashna ◽  
Rubiyah Yusof ◽  
Zool H. Ismail
Keyword(s):  
Numerical Modeling ◽  
Numerical Model ◽  
Crude Oil ◽  
Oil Spill ◽  
Water Surface ◽  
Sea Surface ◽  
Sea Waves ◽  
Robot Locomotion ◽  
Swarm Robots ◽  
Real Time Tracking

An oil spill is discharge of fluid petroleum such as crude oil or its by-product derivations such as diesel and gasoline on the water surface. In this paper, a numerical model of the oil spill has been introduced as a simulation of releasing oil on the sea surface. Meantime, the influence of sea waves and wind has been considered and shown. Moreover, a swarm of robots is engaged in order to track the spreading boundaries of the slicked oil, so that a novel schedule of robot locomotion is presented, based on the online sharing information in the flock network. Therefore, the swarm of robots tracks the oil spill margins intelligently and successfully.

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