scholarly journals Buried Depth of a Submarine Pipeline Based on Anchor Penetration

2019 ◽  
Vol 7 (8) ◽  
pp. 257
Author(s):  
Xueyuan Zhu ◽  
Qinglong Hao ◽  
Jie Zhang
Keyword(s):  
Numerical Simulation ◽  
Penetration Depth ◽  
Water Depth ◽  
Calculation Method ◽  
Water Surface ◽  
Submarine Pipeline ◽  
Projected Area ◽  
Actual Measurement ◽  
Calculation Results ◽  
The Relationship

Anchor penetration is an important issue involved in the study of submarine pipeline damage accidents. To explore the penetration of a ship’s anchor under certain conditions, this study investigated the motion and force of an anchor and formulated a calculation method for the bottoming speed of an anchor. Meanwhile, the depth of anchor penetration was calculated under different conditions according to bottoming speed through programming. Finally, the reliability of the calculation method for the penetration depth was verified by comparing the actual measurement and the numerical simulation. On the basis of the findings, the calculation results were further analyzed, and conclusions were derived regarding the relationship between anchor mass, the horizontal projected area of the anchor, the anchor height on the water surface, and water depth. The conclusions provide suggestions for the application of anchor penetration in terms of seabed depth with certain reference values.

The Research of Calculation Method on Vertical Natural Frequency of the New Full-Prefabricated Floor

2016 ◽  
Vol 846 ◽  
pp. 506-511
Author(s):  
Chong Fang Sun ◽  
Shu Ting Liang ◽  
Xiao Jun Zhu
Keyword(s):  
Numerical Simulation ◽  
Natural Frequency ◽  
Calculation Method ◽  
Variable Stiffness ◽  
Series Method ◽  
Numerical Simulation Result ◽  
Stiffness Method ◽  
Calculation Results ◽  
New Type ◽  
Test Result

New-type floor is composed of three kinds of slabs joined together through fittings. It is a kind of anisotropic two-way slab. In order to study the calculation method of natural frequency, series method, variable thickness method and variable stiffness method are adopted to calculate the natural frequency. The calculation results of three methods are compared with test result and numerical simulation result. The conclusion is that the calculation result of the variable stiffness method is the closest to the real natural frequency of new-type floor.

Numerical Simulation for the Motion of the Flexible Floating Collision-Prevention System

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Xu-jun Chen ◽  
Guang-yuan Huang ◽  
Guang-huai Wu ◽  
Xue-feng Tang
Keyword(s):  
Numerical Simulation ◽  
Model Test ◽  
Calculation Method ◽  
Iterative Calculation ◽  
Collision Prevention ◽  
Prevention System ◽  
Movement Distance ◽  
History Of ◽  
The Relationship ◽  
Good Agreement

The flexible floating collision-prevention system (FFSCS) is a valuable floating engineering structure that can be used to prevent the uncontrolled ships to collide with the non-navigational bridge of a large sea-crossing bridge. The system is composed of buoys, block chains, mooring chains and gravity anchors. The deformation of the system under the acting of an uncontrolled ship as well as the movement distance of the gravity anchors are important factors that should be considered by the system designers. Based on the analysis of the relationship between the forces and the deformation of each part of the system, the approximately static equations are solved by a new numerical iterative calculation method. The position changes of the buoys, the movements of the anchors and the history of the inner forces of the block chains when a ship collides with the FFSCS are obtained by iterative calculation. The good agreement between the numerical value and the results of the model test indicate that the small balance method is a validation on the motion response simulation of the FFSCS under the acting of the uncontrolled ship. The results validate that FFSCS can stop the uncontrolled ship before it arrives at the place of the bridge.

Effects of Mesh Size and Target Dimension on Numerical Simulation of Shaped Charge Liner Penetration into Target

2011 ◽  
Vol 52-54 ◽  
pp. 162-167 ◽  
Author(s):  
Qin Shu Miao ◽  
Xiao Ming Wang ◽  
Yu Zheng
Keyword(s):  
Numerical Simulation ◽  
Penetration Depth ◽  
Mesh Size ◽  
Critical Dimension ◽  
Shaped Charge ◽  
Test Results ◽  
Calculation Time ◽  
Target Dimension ◽  
Simulation Results ◽  
The Relationship

In order to solve two problems when simulating the phenomenon of Shaped Charge Liner penetrating into target, an example was simulated to study the influence of mesh size and target dimension on the penetration results using AUTODYN-2D. The relationship between the Shaped Charge Liner parameters and the critical dimension of the target was gained．The effects of mesh sizes on the penetration depth, aperture，and calculation time were studied. After analyzing the simulation results，a proper range of mesh size was obtained. The simulation results agree well with the test results. The research could provide reference on the simulation of Shaped Charge Liner.

scholarly journals BUDIDAYA RUMPUT LAUT Sargassum sp. DENGAN METODE KANTONG PADA BEBERAPA TINGKAT KEDALAMAN DI DUA WILAYAH PERAIRAN BERBEDA

2018 ◽  
Vol 12 (3) ◽  
pp. 221
Author(s):  
Muslimin Muslimin ◽  
Wiwin Kusuma Perdana Sari
Keyword(s):  
Water Depth ◽  
Confidence Level ◽  
Water Surface ◽  
Growth Response ◽  
Mesh Size ◽  
North Sulawesi ◽  
Highest Weight ◽  
Cultivation Technology ◽  
Seaweed Production ◽  
The Relationship

Optimalisasi produksi rumput laut memerlukan teknologi budidaya yang tepat. Rumput laut Sargassum sp. mudah mengalami kerontokan talus. Hal inilah yang melatarbelakangi perlunya kajian penerapan metode kantong untuk budidaya rumput laut Sargassum sp. Tujuan penelitian ini adalah untuk mengetahui respons pertumbuhan rumput laut Sargassum sp. yang dibudidayakan dengan metode kantong pada beberapa tingkat kedalaman. Penelitian dilakukan di dua lokasi berbeda yakni perairan Kabupaten Pohuwato Provinsi Gorontalo dan perairan Kabupaten Bolaang Mongondow Utara Provinsi Sulawesi Utara pada bulan Maret-Mei 2016. Desain penelitian menggunakan RAL faktorial yang terdiri atas faktor wadah kantong (tanpa kantong, wadah kantong dengan ukuran mata jaring 1,5; 0,75; dan 0,25 inci) dan kedalaman (permukaan 0; 50; 100; 150; dan 200 cm) masing-masing diulang lima kali. Hasil penelitian menunjukkan bahwa faktor wadah kantong dan kedalaman, serta interaksi keduanya berpengaruh terhadap pertumbuhan rumput laut Sargassum sp. pada taraf uji 5% (P<0,05) di kedua lokasi penelitian. Pertumbuhan terbaik diperoleh dari perlakuan K0D0 (tanpa kantong dan di permukaan air) sedangkan pertumbuhan terendah terjadi pada perlakuan K3D4 (kantong meshsize 0,25 inci pada kedalaman 200 cm). Bobot tertinggi di lokasi-I mencapai 235,8 g dan terendah 19,2 g; sedangkan di lokasi-II tertinggi 208,4 g dan terendah 42,2 g. Penggunaan kantong rumput laut kurang efektif dalam memacu pertumbuhan rumput laut Sargassum sp. Pertumbuhan sangat dipengaruhi oleh intensitas cahaya, karenanya budidaya Sargassum sp. perlu memperhatikan faktor kedalaman perairan yang berkorelasi dengan intensitas cahaya matahari.Optimization of seaweed production requires an appropriate cultivation technology. The thallus of Sargassum sp. is easy to break. This was the underlying reason to study the application of bag method in cultivating Sargassum sp. The research aimed to find out the growth response of Sargassum sp. cultivated using bag method at various depth levels. The research was conducted in two different locations, namely Pohuwato Regency Gorontalo and North Bolaang Mongondow Regency North Sulawesi from March to May 2016. The experiment was carried out using the factorial design, consisting of bag factor (without bag; mesh size bag of 1.5; 0.75; and 0.25 inches) and depth factor (surface 0; 50; 100; 150; and 200 cm) with five replications. Results of the research showed that both parameters (bag and the depth factor) and their interaction have affected the growth of Sargassum sp. at 5% confidence level (P<0.05) in both locations. The highest growth response was found in K0D0 treatment (without bag on the water surface) whereas the lowest growth was showed by K3D4 treatment (mesh size bag of 0.25 inches at 200 cm depth). The highest weight at location-I was 235.8 g and the lowest weight was 19.2 g. In location-II, the highest weight was 208.4 g and the lowest was 42.2 g. The use of bags was ineffective in boosting the growth of cultured Sargassum sp. The growth of seaweed is strongly influenced by the intensity of light. Therefore, it is recommended that the cultivation of Sargassum sp. should consider the relationship between the water depth factor and the intensity of sunlight

scholarly journals Estimasi Debit Puncak Menggunakan Hidrograf Satuan Sintetik Pada Daerah Aliran Sungai Kayan Kabupaten Bulungan

2020 ◽  
Vol 3 (2) ◽  
pp. 115-128
Author(s):  
Asta Asta ◽  
Nurjaya Nurjaya
Keyword(s):  
Calculation Method ◽  
Peak Discharge ◽  
Unit Hydrograph ◽  
Flood Discharge ◽  
Synthetic Unit Hydrograph ◽  
Prone Area ◽  
Calculation Results ◽  
Flood Prone Area ◽  
The Relationship

The Kayan Watershed in Bulungan Regency is the largest river in North Kalimantan which has the potential for flooding in several irrigated points. Kayan River is a flood-prone area and prioritized to be handled immediately because there is already a smooth life for the community. Potentially need to know the great potential of flooding in the Kayan River. To find out the relationship between flood discharge and flood time, the Synthetic Unit Hydrograph calculation method is used. The aim is to determine the shape and results of peak discharge in Synthetic Unit Hydrograph Y (SUH). This study uses a debit calculation in the Kayan watershed using Snyder HSS a nd Nakayasu HSS. From the calculation results obtained Snyder SUH peak discharge of 118.0 m3/ sec at 73.85 hours, and Nakayasu SUH has a peak discharge of 109.35 m3 / sec at 54.09 hours.

Numerical Simulations on the Motions of Anchored Capesize Ships

2011 ◽  
Vol 65 (1) ◽  
pp. 145-158
Author(s):  
Youjia Zou ◽  
Chun Shen ◽  
Xiangying Xi
Keyword(s):  
Numerical Simulation ◽  
Water Depth ◽  
Significant Influence ◽  
Environmental Conditions ◽  
Current Velocity ◽  
Wind Force ◽  
Time Model ◽  
New Methods ◽  
External Forces ◽  
The Relationship

When a ship is moored by a single anchor at the anchorage, its combined motions (i.e. yaw, sway, surge, etc.) are usually induced by external forces. Previous studies have gained some insights into the forces on anchor chains, but the motions for Capesize vessels still need to be further investigated. The length of anchor chain required for safe anchoring also needs to be carefully calculated rather than determined solely by the experience and judgement of Captains. The relationship between the length of chain and water depth, wind force, current velocity and the trim (draught difference forward/aft) requires further study. Our new methods consider all necessary factors which may exert significant influence on ships, including not only the water depth at the anchoring location but also the particulars of the ships, its equipment and the environmental conditions. Here, a numerical simulation model to describe the behaviour of an anchored Capesize ship is presented, with the comparison of results between simulations and real time model tests carried out. A discussion highlights the important features of the methods which provide mariners with theoretical solutions.

scholarly journals Hydrodynamic Characteristics of Different Undulatory Underwater Swimming Positions Based on Multi-Body Motion Numerical Simulation Method

2021 ◽  
Vol 18 (22) ◽  
pp. 12263
Author(s):  
Jin Yang ◽  
Tianzeng Li ◽  
Zhiya Chen ◽  
Chuan Zuo ◽  
Xiaodong Li
Keyword(s):  
Numerical Simulation ◽  
Water Depth ◽  
Water Surface ◽  
Swimming Performance ◽  
Simulation Method ◽  
Lateral Position ◽  
Body Motion ◽  
Hydrodynamic Characteristics ◽  
Joint Center ◽  
Multi Body

The study of hydrodynamic characteristics of swimming is the main way to optimize the swimming movement. The relationship between position, water depth, and swimming performance of undulatory underwater swimming are one of the main concerns of scholars. Therefore, the aim of this study is to analyze the swimming performance of three different undulatory underwater swimming positions under various swimming depths using a numerical simulation method based on multi-body motion. The simulation was conducted using 3D incompressible Navier–Stokes equations using the RNG k-ε turbulence closure equations, and in combination with the VOF method thus that we could include the water surface in our calculations. Different swimming depths based on the distance from the shoulder joint center to the initial water surface were considered. The velocity of the shoulder joint center was captured with a swimming motion monitoring system (KiSwim) and compared with the calculated results. The study found that there was a significant difference in the hydrodynamic characteristics of the three undulatory underwater swimming positions (i.e., the dorsal, lateral, and frontal positions) when swimming near the water surface, and the difference decreased as the swimming depth increased. There was a negative correlation (R(dorsal)= −0.928, R(frontal)= −0.937, R(lateral)= −0.930) between the swimming velocities of the three undulatory underwater swimming positions and the water depth (water depth= 0.2–0.7 m) and that the lateral position had the greatest average velocity. Therefore, it is recommended that swimmers travel at least 0.5 m below the water surface in any undulatory underwater swimming position in order to avoid excessive drag forces. As the swimmer approaches the water surface, the lateral position is worth considering, which has better velocity and hydrodynamic advantage than the other two undulatory underwater swimming positions.

Numerical Modeling of the Effects of Wears on Cutting Loads

2011 ◽  
Vol 308-310 ◽  
pp. 2340-2344 ◽  
Author(s):  
Xiao Yu Wang ◽  
Zong Xi Cai ◽  
Peng Cheng Su ◽  
Hai Feng Zhao ◽  
Yi Lan Kang
Keyword(s):  
Numerical Simulation ◽  
Numerical Modeling ◽  
Numerical Simulations ◽  
Penetration Depth ◽  
Normal Force ◽  
Disc Cutter ◽  
Fem Model ◽  
Simulation Results ◽  
Modified Formula ◽  
The Relationship

In order to determine the normal force acting on the TBM disc cutter, a 3-D FEM model is established to simulate the cutting process, with the failure effect of the rock. Afterwards, by using this model, a series of numerical simulations are performed. Based on the numerical simulation results, via modifying Evans formula, an improved formula is given. The modified formula indicates the relationship between the normal force acting on a single disc cutter and the penetration depth, and contains the influence of formation stress and wear.

The Accurate Analysis of Magnetic Force of Bi-Stable Piezoelectric Cantilever Energy Harvester

2017 ◽  
Author(s):  
Yu-Yang Zhang ◽  
Yong-Gang Leng ◽  
Sheng-Bo Fan
Keyword(s):  
Energy Harvesting ◽  
Calculation Method ◽  
Magnetic Force ◽  
Shape Function ◽  
Accurate Analysis ◽  
Piezoelectric Cantilever ◽  
Calculation Results ◽  
Energy Harvesting System ◽  
Time Position ◽  
The Relationship

In the study of nonlinear bi-stable piezoelectric cantilever energy harvesting system, the accuracy of magnetic force’s calculation on which the potential function and dynamics of the system depend is essential to predict the output response and energy harvesting effect. In this paper, we built a shape function to calculate the trace of the end of the beam with the integral of the entire cantilever beam’s slope, and the magnetic force is consequently derived from the achieved magnets’ real-time position and posture using the magnetizing currents method. With the comprehensive consideration of axial magnetic force and lateral magnetic force, the change of both resultant magnetic force’s value and direction are achieved. The simulation results demonstrate that when the displacement of the magnet at the end of the beam is large enough, the axial and lateral magnetic forces change turn from repulsion to attraction, which leads to a large veer of the direction of resultant magnetic force across two quadrants. And the relationship between magnetic force and interval between two magnets is also achieved. The calculation results of this work are nicely consistent with experimental data. So, the accuracy of this calculation method has been proved to be much higher than the existing calculation method.

scholarly journals Numerical Simulation of Intrachamber Processes in the Power Plant

2021 ◽  
Vol 11 (11) ◽  
pp. 4990
Author(s):  
Boris Benderskiy ◽  
Peter Frankovský ◽  
Alena Chernova
Keyword(s):  
Numerical Simulation ◽  
Power Plant ◽  
Flow Structure ◽  
Power Plants ◽  
Control Volume ◽  
Conjugate Problem ◽  
Topological Features ◽  
Gas Dynamic ◽  
Calculation Results ◽  
Volume Method

This paper considers the issues of numerical modeling of nonstationary spatial gas dynamics in the pre-nozzle volume of the combustion chamber of a power plant with a cylindrical slot channel at the power plant of the mass supply surface. The numerical simulation for spatial objects is based on the solution conjugate problem of heat exchange by the control volume method in the open integrated platform for numerical simulation of continuum mechanics problems (openFoam). The calculation results for gas-dynamic and thermal processes in the power plant with a four-nozzle cover are presented. The analysis of gas-dynamic parameters and thermal flows near the nozzle cover, depending on the canal geometry, is given. The topological features of the flow structure and thermophysical parameters near the nozzle cap were studied. For the first time, the transformation of topological features of the flow structure in the pre-nozzle volume at changes in the mass channel’s geometry is revealed, described, and analyzed. The dependence of the Nusselt number in the central point of stagnation on the time of the power plants operation is revealed.

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