scholarly journals Numerical Study on the Hydrodynamic Characteristics of Submarine Pipelines under the Impact of Real-World Tsunami-Like Waves

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 221 ◽  
Author(s):  
Enjin Zhao ◽  
Ke Qu ◽  
Lin Mu ◽  
Simon Kraatz ◽  
Bing Shi
Keyword(s):  
Solitary Wave ◽  
Wave Height ◽  
Real World ◽  
Oil And Gas ◽  
High Efficiency ◽  
Numerical Study ◽  
Hydrodynamic Forces ◽  
Hydrodynamic Characteristics ◽  
Tsunami Waves ◽  
The Impact

Submarine pipelines have been extensively used for marine oil and gas extraction due to their high efficiency, safety, and low price. However, submarine pipelines are vulnerable to extreme waves (i.e., tsunami waves). Previous research has often used solitary waves as a basis for studying the impacts of tsunami waves on submarine pipelines, although the hydrodynamic characteristics and wave properties drastically differ from those of real-world tsunami waves. This paper numerically investigates the hydrodynamic characteristics of tsunami waves interacting with submarine pipelines, but instead uses an improved wave model to generate a tsunami-like wave that more closely resembles those encountered in the real-world. The tsunami-like wave generated based on a real-world tsunami wave profile recorded during a 2011 tsunami in Japan has been applied. Given the same wave height, simulation results show that peak hydrodynamic forces of the tsunami-like wave are greater than those of the solitary wave. Meanwhile, the duration of the acting force under the tsunami-like wave is much longer than that of the solitary wave. These findings underline the basic reasons for the destructive power of tsunamis. It is also noted that the hydrodynamic forces of the pipeline under the tsunami-like wave increase with wave height, but will decrease as water depth increases. In addition to the single pipeline, the complicated hydrodynamic characteristics of pipelines in tandem arrangement have been also numerically studied. It is believed that the findings drawn from this paper can enhance our understanding of the induced forces on submarine pipelines under extreme tsunami waves.

scholarly journals NUMERICAL STUDY OF ACOUSTIC CHARACTERISTICS OF A DTMB 4119 PROPELLER DUE TO TIP RAKE

2019 ◽  
Author(s):  
Danio Joe ◽  
Vijit Misra ◽  
R Vijayakumar
Keyword(s):  
Marine Mammals ◽  
Numerical Study ◽  
Hydrodynamic Performance ◽  
Hydrodynamic Characteristics ◽  
Acoustic Characteristics ◽  
Radiated Noise ◽  
Propeller Noise ◽  
Disk Plane ◽  
Propeller Geometry ◽  
The Impact

The impact of increased Underwater Radiated Noise (URN) over the past two decades on marine mammals has resulted in the pressing requirement to reduce it. Shipping contributes immensely to the URN. Propeller noise is a major source of URN. The reduction in Propeller noise can hence significantly help in the reduction of URN. With the sole objective of improving the hydrodynamic performance of propellers ways to prevent cavitation are being developed. However, the reduction of non cavitating noise produced by the propeller would still remain a challenge. The change in the propeller geometry can modify the acoustic characteristics. In this present study, effect of modifying the tip of DTMB4119 propeller on the acoustic and hydrodynamic characteristics is presented. The change in the flow pattern at the tip due to introduction of tip rake is also discussed. The SPL has been calculated by using the two-step Ffowcs William and Hawkings (FW-H) equations from the pressure distribution at various points around the propeller. SPL at various points in the downstream and propeller disk plane are numerically predicted and discussed.

scholarly journals The hydrodynamic conditions of the Volyn-Podillya oil and gas-bearing region

2018 ◽  
Keyword(s):  
Oil And Gas ◽  
Water Pressure ◽  
The State ◽  
Upper Devonian ◽  
State Enterprise ◽  
Hydrodynamic Characteristics ◽  
Gas Field ◽  
Hydrodynamic Field ◽  
The Impact ◽  
Gas Bearing

The purpose of the paper was to study hydrodynamic peculiarities of the aquifers of Volyn-Podillya oil and gas-bearing region and their impact on the formation and conservation of gas deposits. The research area is located in the western Ukraine and covers the structures of the Eastern European and the Western European platforms. At present, Lokachi and Velyki Mosty gas fields are discovered here in the deposits of the Middle and Upper Devonian. Non-commercial volumes of gas and oil were received in some exploration wells. Research methodology was based on the evaluation of water initial formation pressures and static levels that were obtained from the funds of the State Enterprise "Lvivgazvydobuvannia" and State Enterprise "Zakhidukrgeologia”. The formation pressures were transformed to one plane of comparison. Also the hydrodynamic characteristics were studied in this work on the basis of the hydrostatic coefficient (P f/P e) in order to evaluate the impact of the factors that determine the nature and form the state of the hydrodynamic field. The maps of the formation pressures and hydrostatic coefficients were constructed and interpreted. Results of researches. It was found out that the parameters of hydrodynamic fields of the Upper Proterozoic, Cambrian, and Lower-Devonian aquifers complexes of the Volyn-Podillya ORG have the features of an exfiltration system. The hydrodynamic tension extends from the most abyssal parts of the sedimentary basin to its peripheral parts. Formation pressures are caused by an increase in the volume of waters due to their squeezing out of clay sediments that have the ability to significant compression into weakly compression sandy rocks. The hydrodynamic energy of the Middle-Upper Devonian aquifer complex is directed from the periphery to its central (the most submerged) part. The peripheral parts have the characteristics of the infiltration water-pressure system. It was established that the hydrodynamic field of the Volyn-Podillya ORG compared with the Bilche-Volytsya ORG is marked by a much lower power due to weak effect of exfiltration in the aquifers and the absence of sustained lithological and tectonic screens. The lateral hydrodynamic field, investigated on the basis of the hydrostatic coefficient, increases from the south to the north. A certain spatial relationship of the isolines of hydrostatic coefficient with diagonal disjunctive breaks is observed. This can determine them as a way of the water-hydrocarbon mixtures migration. Gas deposits of Lokachy and Velyki Mosty fields are located in areas with higher values of the hydrostatic coefficient. Distribution of the hydrostatic coefficient in the section of Lokachi gas field indicates the connection of its overhydrostatic values with the existing gas deposits. Hydrodynamic isolation of the structures promoted conservation of hydrocarbon deposits from mechanical and biochemical destruction.

An Experimental and Numerical Study of a Hydrogen Fueled, Directly Injected, Heavy Duty Engine at Knock-Limited Conditions

2020 ◽  
Author(s):  
Joel Mortimer ◽  
Stephen Yoannidis ◽  
Farzad Poursadegh ◽  
Zhewen Lu ◽  
Michael Brear ◽  
...  
Keyword(s):  
High Efficiency ◽  
Numerical Study ◽  
Engine Performance ◽  
Cylinder Pressure ◽  
Heavy Duty ◽  
Ignition Timing ◽  
High Compression Ratio ◽  
Combustion Modeling ◽  
Wide Range ◽  
The Impact

Abstract This paper presents an experimental and numerical study of a directly injected, spark-ignited (DI SI), heavy duty hydrogen fueled engine at knock-limited conditions. The impact of air-fuel ratio and ignition timing on engine performance is first investigated experimentally. Two-zone combustion modeling of the hydrogen fueled cylinder is then used to infer burn profiles and unburned, end-gas conditions using the measured in-cylinder pressure traces. Simulation of the autoignition chemistry in this end-gas is then undertaken to identify key parameters that are likely to impact knock-limited behavior. The experiments demonstrate knock-limited performance on this high compression ratio engine over a wide range of air-fuel ratios, λ. Other trends with λ are qualitatively similar to those shown in previous studies of hydrogen fueled engines. Kinetic simulations then suggest that some plausible combination of residual nitric oxide from previous cycles and locally high charge temperatures at intake valve closing can lead to autoignition at the knock-limited conditions identified in the experiments. This prompts a parametric study that shows how increased λ makes hydrogen less likely to autoignite, and suggests options for the design of high efficiency, directly injected, hydrogen fueled engines.

scholarly journals 1D numerical study on hydrogen injection enabling ultra-lean combustion in a small gasoline Spark Ignition engine

2020 ◽  
Vol 197 ◽  
pp. 06001
Author(s):  
Luigi Teodosio ◽  
Dino Pirrello ◽  
Luca Marchitto
Keyword(s):  
High Efficiency ◽  
Laminar Flame ◽  
Numerical Study ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Pollutant Emissions ◽  
Numerical Code ◽  
Hydrogen Addition ◽  
1D Model ◽  
The Impact

This paper deals with the effects of hydrogen port injection on combustion evolution, efficiency and exhaust emissions of a small turbocharged gasoline Spark-Ignition engine through a 1D numerical code. First, the experiments on the base engine architecture are performed at different speeds and at low/medium loads. The experimental findings are used to validate a 1D model of the whole engine, developed within a commercial code. 1D model is also refined with “user-defined” sub-models for an accurate description of the in-cylinder phenomena, namely turbulence, combustion, heat transfer, and emissions. In a second step, 1D model is virtually modified through the installation of an hydrogen injector in each intake runner, while the combustion sub-model also accounts for the impact of hydrogen addition on the laminar flame speed through a dedicated correlation. 1D simulations are performed at low/medium loads and fixed speed of 2250 rpm with 5% of hydrogen by volume in the intake air. Numerical investigations show that hydrogen addition to gasoline/air mixtures allows relevant efficiency benefits (up to a maximum percent gain of 19%), while the NO emissions are almost eliminated. Consequently, hydrogen-boosted combustion represents a potential solution to achieve very high efficiency and reduced pollutant emissions of gasoline spark ignition engines equipped with a conventional combustion system.

scholarly journals A Numerical Study on a Flopper Stopper for Leg Positioning of a Jack-Up Barge

2017 ◽  
Author(s):  
Zhiyu Jiang ◽  
Wilson Guachamin Acero ◽  
Zhen Gao ◽  
Lin Li
Keyword(s):  
Wave Height ◽  
Structural Damage ◽  
Oil And Gas ◽  
Numerical Study ◽  
Coupled System ◽  
Offshore Wind ◽  
Maximum Increase ◽  
Peak Period ◽  
Global Dynamic ◽  
Jack Up

Jack-up barges are commonly used for marine operations in the offshore oil and gas, and offshore wind industries. A critical phase within the marine operation activities is the positioning of the jack-up legs onto the seabed. During this process, large impact velocities and forces may arise from the barge’s heave, roll and pitch motions, and structural damage of the legs can occur. This paper numerically investigates the effect of a flopper stopper (FS) on the motion responses of a jack-up barge from the offshore wind industry. The FS is known as a passive roll compensation device. It is suspended from the side of the barge by means of wire ropes and cantilever beams. A simple geometry of an FS is proposed, and the working principle introduced. For the loading condition before the leg-soil impact occurs, global dynamic analyses of the coupled system are conducted. Characteristic values of impact velocities are used to establish the jack-up operational limits in terms of the significant wave height and peak period. By comparing the operational limits for the barge with and without FS, it is found that FS should be placed on the weather side. At beam seas, the current FS can lead to a maximum increase in the operational wave height limit of 35%, whereas for the other wave headings, it may not be beneficial to use FS.

Piezoelectric β-polymorph formation of new textiles by surface modification with coating process based on interfacial interaction on the conformational variation of poly (vinylidene fluoride) (PVDF) chains

2020 ◽  
Vol 91 (3) ◽  
pp. 31301
Author(s):  
Nabil Chakhchaoui ◽  
Rida Farhan ◽  
Meriem Boutaldat ◽  
Marwane Rouway ◽  
Adil Eddiai ◽  
...  
Keyword(s):  
High Efficiency ◽  
Vinylidene Fluoride ◽  
Research Work ◽  
Research Area ◽  
Interfacial Interaction ◽  
Tetraethyl Orthosilicate ◽  
Poly Vinylidene Fluoride ◽  
Carbon Nanofillers ◽  
The Impact ◽  
Advanced Applications

Novel textiles have received a lot of attention from researchers in the last decade due to some of their unique features. The introduction of intelligent materials into textile structures offers an opportunity to develop multifunctional textiles, such as sensing, reacting, conducting electricity and performing energy conversion operations. In this research work nanocomposite-based highly piezoelectric and electroactive β-phase new textile has been developed using the pad-dry-cure method. The deposition of poly (vinylidene fluoride) (PVDF) − carbon nanofillers (CNF) − tetraethyl orthosilicate (TEOS), Si(OCH2CH3)4 was acquired on a treated textile substrate using coating technique followed by evaporation to transform the passive (non-functional) textile into a dynamic textile with an enhanced piezoelectric β-phase. The aim of the study is the investigation of the impact the coating of textile via piezoelectric nanocomposites based PVDF-CNF (by optimizing piezoelectric crystalline phase). The chemical composition of CT/PVDF-CNC-TEOS textile was detected by qualitative elemental analysis (SEM/EDX). The added of 0.5% of CNF during the process provides material textiles with a piezoelectric β-phase of up to 50% has been measured by FTIR experiments. These results indicated that CNF has high efficiency in transforming the phase α introduced in the unloaded PVDF, to the β-phase in the case of nanocomposites. Consequently, this fabricated new textile exhibits glorious piezoelectric β-phase even with relatively low coating content of PVDF-CNF-TEOS. The study demonstrates that the pad-dry-cure method can potentially be used for the development of piezoelectric nanocomposite-coated wearable new textiles for sensors and energy harvesting applications. We believe that our study may inspire the research area for future advanced applications.

Consideration of Geopolitical Challenges within the Analysis of Geoenvironmental Risks for Oil and Gas Development of the Russian Arctic

2019 ◽  
Vol 16 (6) ◽  
pp. 50-59
Author(s):  
O. P. Trubitsina ◽  
V. N. Bashkin
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Optimal Operation ◽  
The Arctic ◽  
Stage Model ◽  
Oil And Gas Development ◽  
Gas Industry ◽  
The Impact ◽  
Further Development ◽  
Geopolitical Risks

The article is devoted to the consideration of geopolitical challenges for the analysis of geoenvironmental risks (GERs) in the hydrocarbon development of the Arctic territory. Geopolitical risks (GPRs), like GERs, can be transformed into opposite external environment factors of oil and gas industry facilities in the form of additional opportunities or threats, which the authors identify in detail for each type of risk. This is necessary for further development of methodological base of expert methods for GER management in the context of the implementational proposed two-stage model of the GER analysis taking to account GPR for the improvement of effectiveness making decisions to ensure optimal operation of the facility oil and gas industry and minimize the impact on the environment in the geopolitical conditions of the Arctic.The authors declare no conflict of interest

1607-P: Real-World Evidence of the Impact of Obesity on Residual Teeth in the Japanese Population

Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 1607-P
Author(s):  
MAYU HAYASHI ◽  
KATSUTARO MORINO ◽  
KAYO HARADA ◽  
MIKI ISHIKAWA ◽  
ITSUKO MIYAZAWA ◽  
...  
Keyword(s):  
Real World ◽  
Japanese Population ◽  
Real World Evidence ◽  
The Impact
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