Development of Design Technologies for Optimum Moonpool Shapes of Drill Ship

2007 ◽  
Author(s):  
Jong Jin Park ◽  
Mun Sung Kim ◽  
Hee Sung Lee ◽  
Young Kyu Ahn ◽  
Young Bok Kim ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Free Surface ◽  
Input Data ◽  
Three Dimensional ◽  
Ship Motions ◽  
Surface Movement ◽  
Seakeeping Analysis ◽  
Simulation Results ◽  
Six Degree Of Freedom ◽  
Rough Sea

The present study is concerned with the numerical and experimental analysis of a moonpool in rough sea. From hydrodynamic viewpoint, a moonpool of drill ships can cause various problems. Among them, two major problems arise such as an increased resistance and overflow on the deck due to pumping up phenomena. To overcome these inherit problems, we have carried out various numerical analysis to find optimum moonpool shapes. The three-dimensional numerical model adopting SOLA-VOF scheme is used to predict violent free surface movement inside of a moonpool due to irregular ship motions with six degree of freedom. For accurate input data of ship motions, a three dimensional panel method program is applied for seakeeping analysis. The resistance and seakeeping model test have been carried out at MARINE to validate the proposed moonpool shapes, which have been designed based on numerical simulation results.

Prediction of Ship Motions Via a Three-Dimensional Time-Domain Method Following a Quad-Tree Adaptive Mesh Technique

2020 ◽  
Vol 27 (1) ◽  
pp. 29-38
Author(s):  
Teng Zhang ◽  
Junsheng Ren ◽  
Lu Liu
Keyword(s):  
Free Surface ◽  
Incident Wave ◽  
Time Domain ◽  
Three Dimensional ◽  
Adaptive Mesh ◽  
Wave Profile ◽  
Time Domain Method ◽  
Ship Motions ◽  
Quad Tree ◽  
Mesh Technique

AbstractA three-dimensional (3D) time-domain method is developed to predict ship motions in waves. To evaluate the Froude-Krylov (F-K) forces and hydrostatic forces under the instantaneous incident wave profile, an adaptive mesh technique based on a quad-tree subdivision is adopted to generate instantaneous wet meshes for ship. For quadrilateral panels under both mean free surface and instantaneous incident wave profiles, Froude-Krylov forces and hydrostatic forces are computed by analytical exact pressure integration expressions, allowing for considerably coarse meshes without loss of accuracy. And for quadrilateral panels interacting with the wave profile, F-K and hydrostatic forces are evaluated following a quad-tree subdivision. The transient free surface Green function (TFSGF) is essential to evaluate radiation and diffraction forces based on linear theory. To reduce the numerical error due to unclear partition, a precise integration method is applied to solve the TFSGF in the partition computation time domain. Computations are carried out for a Wigley hull form and S175 container ship, and the results show good agreement with both experimental results and published results.

scholarly journals MEMS-Based Integrated Triaxial Electrochemical Seismometer

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1156
Author(s):  
Wenjie Qi ◽  
Bowen Liu ◽  
Tian Liang ◽  
Jian Chen ◽  
Deyong Chen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Ground Motion ◽  
Small Volume ◽  
Three Dimensional ◽  
Experimental Results ◽  
Good Prospect ◽  
High Symmetry ◽  
Noise Levels ◽  
Sensitivity Curves ◽  
Simulation Results

This paper presents a micro-electromechanical systems (MEMS)-based integrated triaxial electrochemical seismometer, which can detect three-dimensional vibration. By integrating three axes, the integrated triaxial electrochemical seismometer is characterized by small volume and high symmetry. The numerical simulation results inferred that the integrated triaxial electrochemical seismometer had excellent independence among three axes. Based on the experimental results, the integrated triaxial electrochemical seismometer had the advantage of small axial crosstalk and could detect vibration in arbitrary directions. Furthermore, compared with the uniaxial electrochemical seismometer, the integrated triaxial electrochemical seismometer had similar sensitivity curves ranging from 0.01 to 100 Hz. In terms of random ground motion response, high consistencies between the developed integrated triaxial electrochemical seismometer and the uniaxial electrochemical seismometer could be easily observed, which indicated that the developed integrated triaxial electrochemical seismometer produced comparable noise levels to those of the uniaxial electrochemical seismometer. These results validated the performance of the integrated triaxial electrochemical seismometer, which has a good prospect in the field of deep geophysical exploration and submarine seismic monitoring.

Numerical Simulation of the Kinetic Energy Projectile Oblique Penetration into the Concrete

2014 ◽  
Vol 989-994 ◽  
pp. 982-985
Author(s):  
Jun Chen ◽  
Xiao Jun Ye
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Kinetic Energy ◽  
Three Dimensional ◽  
Test Results ◽  
Destruction Process ◽  
3D Finite Element ◽  
Finite Element Software ◽  
Simulation Results ◽  
Target Characteristics

ANSYS-LS/DYNA 3D finite element software projectile penetrating concrete target three-dimensional numerical simulation , has been the target characteristics and destroy ballistic missile trajectory , velocity and acceleration and analyze penetration and the time between relationship , compared with the test results , the phenomenon is consistent with the simulation results. The results show that : the destruction process finite element software can better demonstrate concrete tests revealed the phenomenon can not be observed , estimated penetration depth and direction of the oblique penetration missile deflection .

scholarly journals Control Technology of Surface Movement Scope with Directional Hydraulic Fracturing Technology in Longwall Mining: A Case Study

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3480 ◽  
Author(s):  
Zhanjie Feng ◽  
Wenbing Guo ◽  
Feiya Xu ◽  
Daming Yang ◽  
Weiqiang Yang
Keyword(s):  
Numerical Simulation ◽  
Hydraulic Fracturing ◽  
Longwall Mining ◽  
Numerical Models ◽  
Surface Subsidence ◽  
The Sustainable Development ◽  
Surface Movement ◽  
Directional Hydraulic Fracturing ◽  
Simulation Results ◽  
Overlying Strata

Mining-induced surface subsidence causes a series of environmental hazards and social problems, including farmland destruction, waterlogging and building damage in the subsidence area. To reduce mining damages, an innovative method of controlling the surface movement scope via artificial weak planes generated by hydraulic fracturing technology was proposed in this paper. Numerical models were built to analyze the influence of weak planes with different heights and dips on the overlying strata movement. The numerical simulation results showed that the weak planes structure cut off the development of the overlying strata displacement to the surface and affected the surface movement scope. When the weak planes’ dips were bigger than the angle of critical deformation, with the increase of the weak planes’ heights (0–120 m) the advance angle of influence changed from 53.61° to 59.15°, and the advance distance of influence changed from 173.31 m to 140.27 m which decreased by 30.04 m. In applications at Sihe coal mine in China, directional hydraulic fracturing technology was used in panel 5304 to form artificial weak planes in overlying strata. The measured surface subsidence and deformation value met the numerical simulation results and the mining-induced surface movement scope reduced. Moreover, no damage occurred to the surface buildings which were predicted to be in the affected area after extraction. This technology provided a new method to protect the surface structures from damages and had great benefits for the sustainable development of coal mines.

scholarly journals Study on Fluorine Pollution in a Slag Yard

2019 ◽  
Vol 9 (5) ◽  
pp. 847
Author(s):  
Lide Wei ◽  
Changfu Wei ◽  
Sugang Sui
Keyword(s):  
Numerical Simulation ◽  
Experimental Investigation ◽  
Numerical Simulations ◽  
Solute Transport ◽  
Large Scale ◽  
Three Dimensional ◽  
Simulation Method ◽  
Laboratory Studies ◽  
Survey Results ◽  
Simulation Results

This paper suggests a large-scale three-dimensional numerical simulation method to investigate the fluorine pollution near a slag yard. The large-scale three-dimensional numerical simulation method included an experimental investigation, laboratory studies of solute transport during absorption of water by soil, and large-scale three-dimensional numerical simulations of solute transport. The experimental results showed that the concentrations of fluorine from smelting slag and construction waste soil were well over the discharge limit of 0.1 kg/m3 recommended by Chinese guidelines. The key parameters of the materials used for large-scale three-dimensional numerical simulations were determined based on an experimental investigation, laboratory studies, and soil saturation of survey results and back analyses. A large-scale three-dimensional numerical simulation of solute transport was performed, and its results were compared to the experiment results. The simulation results showed that the clay near the slag had a high saturation of approximately 0.9, consistent with the survey results. Comparison of the results showed that the results of the numerical simulation of solute transport and the test results were nearly identical, and that the numerical simulation results could be used as the basis for groundwater environmental evaluation.

Study on the Principle of Yarn Splicing of Pneumatic Splicer Using Numerical Simulation

2012 ◽  
Vol 588-589 ◽  
pp. 1355-1358
Author(s):  
Xiao Xing ◽  
Guo Ming Ye
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Numerical Results ◽  
Simulation Results

During the splicing process of pneumatic splicer, the principle of yarn splicing is closely related to the flow field inside the splicing chamber. This paper presents a numerical simulation of the flow char-acteristics inside the splicing chamber of the pneumatic splicer. A three-dimensional grid and the realizable tur¬bulence model are used in this simulation. The numerical results of veloc¬ity vectors distribution inside the chamber are shown. Streamlines starting from the two air injectors are also acquired. Based on the simulation, the principle of yarn splicing of the pneumatic splicer is discussed. The airflow in the splicing chamber can be divided into three regions. In addition, the simulation results have well sup¬ported the principle of yarn splicing of pneumatic splicer claimed by the splicing chamber makers.

Numerical Simulation of Seepage Field in Aquifer under the Coal Seam

2014 ◽  
Vol 955-959 ◽  
pp. 3120-3124
Author(s):  
Kai Bian ◽  
Shi Lei Chen ◽  
Xue Yuan Li ◽  
Ying Wang Zhao
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Coal Seam ◽  
Three Dimensional ◽  
Seepage Field ◽  
Limestone Aquifer ◽  
Flow Models ◽  
Hydrogeological Parameters ◽  
Simulation Results ◽  
Technical Basis

In order to figure out seepage field in aquifer under the coal seam, the geology and hydrogeology conditions systematically of study area were analyzed, hydrogeological conceptual model was generalized, mathematical model was built, seepage field of the Taiyuan limestone aquifer was simulated with software Feflow. Simulation results show that hydrogeological parameters of Taiyuan limestone aquifer change greatly in different partitions. The model also indicates the heterogeneity of karst fissure of Taiyuan limestone aquifer. The drainage quantity is from the Ordovician limestone aquifer besides supplying from runoff of upstream and capture excretion of downstream. The research is an attempt to simulate the seepage field in aquifer under coal seam, to some extent, it also provides a technical basis for safe coal mining and as a reference for simulation constructions of three-dimensional groundwater flow models in similar coal mines.

scholarly journals Development of an MTF in ADINA and its application to the study of the Yuxi Basin effect

2021 ◽  
Author(s):  
Tiefei Li ◽  
Xueliang Chen ◽  
Zongchao Li
Keyword(s):  
Numerical Simulation ◽  
Seismic Waves ◽  
Velocity Structure ◽  
Three Dimensional ◽  
Site Effect ◽  
Lumped Mass ◽  
Explicit Finite Element ◽  
Focusing Effect ◽  
Infinite Domains ◽  
Simulation Results

AbstractA three-dimensional multitransmitting formula is developed in ADINA to simulate the input of seismic waves and the scattering of infinite domains at the same time, consistent with the progress of the explicit finite element method of lumped mass. A three-dimensional cube model is built, and a delta pulse wave is input to compare the simulation results with the analytical solutions. The simulation results show that the peak error is 0.2% of the input wave, which meets the requirements of the usual numerical simulation. This method has a certain efficiency advantage in site effect analyses of fine models for localized fields. A velocity structure model of the Yuxi Basin is built, and the associated basin effect is studied by numerical simulation. The distribution of the focusing effect is related to the structure of the narrow east-west and wide north-south features in the Yuxi Basin, and the edge effect is related to the slope of the basin base. A distribution map is given of the amplification effect of ground motion in the basin.

Numerical Simulation and Stereo PIV Test of Inner Flow in a Double Blades Pump

2011 ◽  
Author(s):  
Kai Wang ◽  
Houlin Liu ◽  
Shouqi Yuan ◽  
Minggao Tan ◽  
Yong Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Velocity Field ◽  
Cfd Simulation ◽  
Research Work ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Absolute Velocity ◽  
Operation Condition ◽  
Test Technique ◽  
Simulation Results

A double blades pump is widely used in sewage treatment industry, while at present the research on the internal flow characteristics of the double blades pump is very few. So, the CFD technology and the stereo PIV test technique are applied to study the inner flow in a double blades pump whose specific speed is 110.9. The commercial code FLUENT is used to simulate the inner flow in the double blades pump at 0.6Qd, 0.8Qd, 1.0Qd, 1.2Qd and 1.4Qd. The RNG k-ε turbulence model and SIMPLEC algorithm are used in FLUENT. According to the results of the three-dimensional steady numerical simulation, the distributions of velocity field in the impeller are obtained at the five different operating conditions. The analysis of the numerical simulation results shows that there is an obvious vortex in the impeller passage at off-design conditions. But the number, location and area of the vortex are different from each operation condition. In order to validate CFD simulation results, the stereo PIV is used to test the absolute velocity distribution in the double blades pump at Jiangsu University. The distributions of three-dimensional absolute velocity field at the above five different operating conditions are obtained by the PIV test, and the measured results are compared with the CFD simulation results. The comparison indicates that there are vortexes in impeller passages of the double blades pump under the five operating conditions. But as to the area of the vortex and the relative velocity values of the vortex core, there are some differences between the experiment results and the numerical simulation results. The research work can be applied to instruct the hydraulic design of double blades pumps.

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