International Journal of coastal and offshore engineering

Published by Armenian Green Publishing Co.
Print ISSN: 2538-2667
Publications
Representation of a Platform Economic Life Time
Capital expenditures for the offshore reference wind plant project [14] Downloaded from ijcoe.org at 16:43 +0430 on Saturday June 22nd 2019
Complexity and costly nature of operations involving in the decommissioning process require huge investments to be done during the lifetime of the field for its decommissioning phase of the total project. This work offers a knowledge-based decommissioning alternative strategy selection system for fixed offshore jacket platforms in the Persian Gulf. In this method, the alternative option of installing offshore wind turbines (OWT) as the most probable economic feasible alternative to decommissioning on an abandoned platform jacket structure in the Persian Gulf is proposed. In this regard, costs and benefits study between two strategies are considered; one total decommissioning and the other installing an OWT on the jacket structure of a local platform in the region. It is found that the second strategy is beneficial and saves near 9 million US dollars for company. Furthermore, the company earns the technology and experiences with OWT installation and operations and would be a technical leader in the region for coming years as well as improve the total rate of greenhouse gas emission production in the region.
 
Two numerical models of tsunami generation/propagation have been run in the Makran region. These models are one of the necessary components in the warning systems in this region. The outputs of these models are not in regular international data model standards. In order to get the best result from these models, the models’ outputs must be managed in a database system. An ideal data management system for tsunami warning system has three essential parts included: data convertor, Geographical Information System (GIS) and Relational Database Management System (RDBMS). The schematics and properties of the proposed data management system have been shown in this paper. 3D, spatial, temporal and statistical analysis of tsunami models data exported to the proposed system based on GIS capabilities and data processing routines. Some examples of data analysis of tsunami propagation in the Makran region (north of the Arabian Sea) have been shown.
 
Berm breakwaters are used as protective structures against the wave attack where larger quarry materials as armor stone is scarce, or large quarry materials are available but using berm breakwater lowers the costs considerably. In addition, wave overtopping in berm breakwaters are significantly lower than the traditional ones for equal crest level because of the wave energy dissipation on the berm.The most important design parameter of berm breakwaters is its seaward berm recession which has to be well estimated. In this paper a method has been developed to estimate the front slope recession of berm breakwaters using artificial neural networks with high accuracy. Four different available data-sets from four experimental tests are used to cover wide range of sea states and structural parameters. The network is trained and validated against this database of 1039 data. Comparisons is made between the ANN model and recent empirical formulae to show the preference of new ANN model.
 
The Karun River is considered to be the longest Iranian river with 855 km length. The river is divided into two branches, 4 km away from the Arvand River, which is a branch of the Bahmanshir River in the north of Abadan, and another branch of the Namkarun River (the Azodi Channel) that flows into the Arvand River. The intersection of the Karun River and the Arvand River is important. Also, measuring and investigating of hydrodynamic phenomena have a vital role in recognizing and prediction the hydrodynamic changes in the region. Therefore, CTD and hydrographic studies were carried out for the Azodi Channel, which is the intersection of the Karun River and the Arvand River. These studies include measurements of marine phenomena such as tidal observations, water level changes, hydrography, topography, CTD and sedimentation. Studies have shown that floods of the Karun River have caused significant changes in the intersection of the rivers Karun and Arvand. Also, the sediment of the study area is fine-grained, but at the intersection of the rivers Arvand and Karun, it is coarse-grained. Sediment concentration is increased in depth, and the lowest and highest sediment concentrations are related to Karun station and Arvand Karun intersection respectively. Regarding the alignment survey, it was found that the current of the study area is mixed current, but mostly meridian. The flow of the Karun River is one of the parameters affecting the water level. So that if the current of the river is noticeable, it will prevent the tidal wave from spreading into the river.
 
In this study two numerical models, one a regional generation and propagation model and the other an inundation model, have been applied to the problem of examining the impact that a large, locally generated tsunami could have on Chabahar Bay facilities in Iran. To achieve a realistic outlook of tsunami hazards in the area, the generation, propagation and interaction of tsunami waves with Chabahar Bay coasts is being numerically modeled for specific events. The modeling is performed using the numerical code which solves the nonlinear Boussinesq wave equations. Results of numerical simulations performed in this study considering past tsunami occurrence records indicate that the multipurpose Chabahar Port is expected to experience the tsunami events with heights ranging between 8 to 10 meters. The model gives approximately the observed maximum area of flooding of Chabahar City. The large amount of flooding of Chabahar city coasts, Iran from the 9.1 magnitude earthquake and small amount of flooding from the 8.3 magnitude earthquake achieved and extensively flooding Chabahar City was reproduced by the numerical model. The effect of the tide was modeled and found to be small. The results of this study are intended for emergency planning purposes. Appropriate use would include the identification of evacuation zones. The results are used also to find a best configuration advice for the urban facilities in order to mitigate tsunami related risks, with positioning such facilities at the Western Cape of the bay.
 
The coastline is defined as an edge or land margin by the sea. Managing such ecological environments in terms of continuous changes requires monitoring at different intervals. To do this, it is necessary to use remote sensing techniques to detect and analyze coastline variations. Two study areas located on the coast of the Persian Gulf (South part of the Qeshm Island and the port of Tien to Asaluyeh) have been studied by two types of optical and radar images and wavelet edge detection algorithm for coastline extracting. In this study, the coastline is extracted in two ways, firstly the coastline extracts from both optical and radar images separately, then by images fusion using wavelet-IHS method. The accuracy obtained in Qeshm area in 2009 from optical, radar and fused images was 3.4, 5.5 and 3.2 respectively, and in Asaluyeh region in 2007, 2.1, 3.4 and 2.98 respectively.
 
The relative stress concentration factors (SCF) on the chord member of a tubular T-joint strengthened with FRP which is subjected to brace axial loading are studied. ABAQUS Finite Element software package is used to perform the numerical analyses. Prior to the main studies, the unstiffened joint was validated against the API and Lloyd’s Register equations together with the experimental data. Six different types of FRP materials such as Glass/Vinyl ester, Glass/Epoxy (Scotch ply 1002), S-Glass/Epoxy, Aramid/Epoxy (Kevlar 49/Epoxy), Carbon/Epoxy (T300-5208) and Carbon/Epoxy (AS/3501) are used as strengthening material in order to enhance the fatigue life of tubular T-joints through lowering the SCFs. Promising results derived from analyses which show that FRP strengthening method can be considered as an effective method for decreasing the SCF values at tubular T-joints. Results of the analyses for 6mm CFRP layup revealed that under the action of axial loading the FRP strengthening could decrease the SCFs up to 30% and 50% at crown and saddle points of the chord member.
 
Location of Nowshahr in the Southern Caspian Sea, b) Nowshahr Port and the study area, c) Bathymetry of the studied area (31) 
Correlation of IGWs with sea waves for nonbreaking condition 
In this study, the evolution and dependency of infragravity waves (IGWs) on wind waves for breaking and nonbreaking conditions is separately investigated. The efficiency of two constant cutoff frequencies (0.125 and 0.14 Hz) is compared for wave data measured in the sandy beaches of Nowshahr at the Southern Caspian Sea. It is found that the frequency of 0.125 Hz results higher correlation coefficients between IGWs energy content and two wind wave groups. Two pair different correlation patterns between IGWs in one side and wind waves higher and lower than 0.125 Hz in another side were recognized for breaking and nonbreaking conditions. In can be concluded that the IGWs excitation is controlled by the frequency distribution of wind wave energy. According to 0.125 Hz as more successful option, the correlation of IGWs with swell waves is generally more significant than sea waves. In the nonbreaking wave condition, the IGWs are well correlated with sea waves, whereas no considerable correlation between IGWs and sea waves is found in the breaking condition. It is resulted that IGWs energy is approximately linearly proportional of both swell and sea waves in nonbreaking condition. In the high and moderate energy incident wave conditions, the IGWs energy grows shoreward, while energy attenuation can be detected for IGWs in very low energy waves.
 
The specification of tested beams
Bars specifications used in this study
The bars specification in fabricated specimens
High Strength Concrete (HSC) is a complex type of concrete, that meets the combination of performance and uniformity at the same time. This paper demonstrates the use of artificial neural networks (ANN) to predict the deflection of high strength reinforced concrete deep beams, which are one of the main elements in offshore structures. More than one thousand test data were collected from the experimental investigation of 6 deep beams for the case of study. The data was arranged in a format of 10 input parameters, 2 hidden layers, and 1 output as network architecture to cover the geometrical and material properties of the high strength self-compacting concrete (HSSCC) deep beam. The corresponding output value is the deflection prediction. It is found that the feed forward back-propagation neural network, 15 & 5 neurons in first and second, TRAINBR training function, could predict the load-deflection diagram with minimum error of less than 1% and maximum correlation coefficient close to 1.
 
A strong low level jet (LLJ) in the northern region of the Persian Gulf (PG) observed on 5th Jun 2020 that sank the Behbahan cargo vessel. In this article, we have used the WRF-V3 model and reanalysis ERA5 data to study the vertical structure, diurnal variation and intensity of the LLJs. The aimed topography’s region, the pressure gradient and the land-sea breeze are the essential key factors in analyzing the diurnal variation of the LLJ over the PG that is known as the Shamal wind. The low terrain height in the northern of the PG and Zagros Mountains channelized the northwest winds and increased the pressure gradient that increased the wind speed. The decreasing friction over the PG during nighttime and the differences in temperature and specific heat capacity between water and land cause an increase in the LLJ intensity. The LLJ’s core 22-24 ms-1 was located over the study region in 925hPa on 4th and 5th June at 18 and 00 UTC respectively. Thereafter core’s wind speed decreased to 10-14 ms-1at 12UTC on 5th June. The mix-down of momentum from the LLJ level to the surface caused an increase in wind speed and wave height over the PG which sank the Behbahan cargo vessel at early morning of 5th June. The LLJ at some regions like Kuwait formed at lower heights (under 950 hPa) and at the other points LLJ formed at levels upper than 950 hPa during nighttime of 4th Jun to afternoon of 5th Jun.
 
One of the issues that emerge from an efficacious design of berm breakwaters is an estimation of wave reflection. In the present study, the wave reflection of a multi-layer berm breakwater (MLBB) has been studied based on model experimentation. To gain this goal, two-dimensional model tests have been carried out in a wave flume at Tarbiat Modares University. Irregular waves were generated using the JONSWAP spectrum, under which the effect of various parameters like wave height, wave period, water depth, and berm elevation from still water level is investigated on the wave reflection. Achieved outcomes of this study propose a new formula estimating MLBBs wave reflection. Ultimately, the performance of the derived formula against the existing formulae proposed by other researchers is checked thoroughly. The results of the statistical evaluation indices divulge that the predicted wave reflection using the new formula is more accurate than the existing ones. Thus, it would be obvious that the present formula can provide a well-founded estimation of wave reflection on the MLBBs. Moreover, the new formula and those estimated by existing ones are validated by employing the data set exclusively used in drawing the comparison. This fair validation illustrates that the current formula is more accurate than the existing formulae.
 
Two major research programs on the use of heuristics in decision-making exist,and each has its own set of followers. The first program was initiated byKahneman and Tversky in the 70s. They primarily concentrated on the errorscaused by using heuristics. This has now grown into many heuristics namedafter their associated biases. The second program was initiated by Gigerenzerand colleagues in Germany. Gigerenzer argues that although simple heuristicssometimes leads to “biased” decisions, they can deliver better answers in somesituations. This is particularly true for uncertain or complex environments,where there is only a small data sample or there is no time to formally seek anoptimized decision. Gigerenzer and colleagues have generated a substantialbody of evidence that humans use simple heuristics, often with great results.Like Kahneman and Tversky, Gigerenzer’s work has attracted researchersexploring the power of “Fast and Frugal” Heuristics, and how they are used byhumans. This part, of the four-part paper, discusses Kahneman and Gigerenzer'sfindings concerning engineering decision making. Avoiding errors when usingsimple heuristics is discussed in Part IV. (19) (PDF) Rationality for Engineers Part II- Heuristics and Biases. Available from: https://www.researchgate.net/publication/355997319_Rationality_for_Engineers_Part_II-_Heuristics_and_Biases?origin=mail&uploadChannel=re390&reqAcc=Ehsan-Khalili-4&useStoredCopy=0 [accessed Jan 06 2023].
 
Simulated dame break flow by ISPH method with effective viscosity at t=0.3s; a) Without any modification; b) modified kernel; c) modified surface viscosity; d) modified kernel and surface viscosity
Smoothed Particle Hydrodynamic (SPH) is an attractive Lagrangian tool for simulating flows with large displacement at free surface boundary. Two widely used subcategories of this method are Weakly compressible SPH (WCSPH) and truly Incompressible SPH (ISPH) methods. Each method has its individual advantages while there is not yet a global agreement about the preference of one method to another one. In this study, accuracy, stability and efficiency of these methods are compared in simulating dam break flow as a well-known hydraulic problem. To decrease unrealistic particle fluctuation especially at free surface boundary, a practical solution is applied to both methods while keeping their total accuracy. In addition, different solid boundary treatments are studied and their effect on total accuracy and stability of SPH methods are investigated. Based on the results, both ISPH and WCSPH methods can model free surface profiles properly if a proper solid boundary treatment is utilized. Meanwhile, local surface fluctuations can be damped in both methods efficiently by means of the modified surface viscosity. By means of original versions, it is concluded that ISPH method is generally more stable and more accurate particularly in modeling pressure field than WCSPH method. In addition, it is shown that ISPH method is faster than WCSPH method in solving a dam break flow with equal number of particles. On the other hand, ISPH in its original version using the divergence-free velocity scheme suffers from density loss problem. Since a lot of modifications have been introduced till now to overcome defections of both methods, it is not fair to compare methods with different modifications and therefore, similar modifications are applied in this study. Meanwhile, it can be concluded that each method is growing and is going its own way through enhancement.
 
The regional model domain, open boundaries, location of the local model, and the stations used for calibration. The domain of the local model is shown by pentagon. 
Surface dispersion of heat for (a) surface discharge, (b) 5.5-meter submerged outfall, and (c) 10-meter submerged outfall. The corresponding current vectors for the upper layer are also demonstrated 
Desalination plants have become invaluable solutions especially where freshwater resources are scarce. However, the byproduct of their operation is an outflow which is more saline and heated than the ambient water body. This heated plume adversely affects the ecosystem if it is not treated properly. In this study, 3D finite volume coastal and ocean model is employed to address this issue close to Qeshm Island. In addition to calibrating the model, two alternatives are simulated and discussed to mitigate the adverse effects of the heated plume. It is shown that the plume tends to move in the upper layer of the water column due to its lower density than the ambient water. By moving the outfall to deeper parts of the sea—10-meter-deep—the negative effects of the plume significantly decreases and fulfilled the Iran national guidelines. Moreover, due to the mechanism of the Qeshm desalination plant, the spread of salinity is of the least importance compared to the increase in temperature.
 
General circulation in the Persian Gulf (Pous et al. 2013, Reynolds 1993)
Temperature (a), pressure (b), wind speed (c) and wind direction (d) recorded at Bushehr station, January 2013-the black box shows the during the WSW (10th to 16th of January)-Bushehr meteorological station
Symbols used in equations
Marine areas are affected by different atmospheric phenomena such as wind and storm. In this research the effect of a large scale atmospheric phenomenon, known as Winter Shamal Wind, is investigated on the regime of currents and waves in the northwest part of the Persian Gulf. This wind normally occurs for the period of three to seven days, during December to early March. MIKE21 Coupled Model FM was applied to study the pattern of current and waves for this period. To provide the hydrodynamic data for the model and validate the simulated results, the wind data of ECMWF and mast meteorology of coastal synoptic station of Bushehr and wave data of buoy located offshore of Bushehr was used. The results indicated only a slight increase in current speed with no significant change in current direction during Winter Shamal Wind, showing a stable current pattern in northwest of the Persian Gulf. The significant wave height and wave propagation speed for the period of Winter Shamal Wind in comparison with the days prior to the wind show significant changes. The maximum wave speed in the area under investigation reaches up to 1 m/s and the significant wave height is almost 1 meter higher than that of normal situation.
 
Bottom topography of the Caspian Sea (depths in meters).
Monthly mean wind velocity vectors based on the ECMWF ERA15 data set.
Monthly means surface currents (m s -1 ) in the Caspian Sea.
A three-dimensional primitive equation model has been developed to study wind-driven currents in the Caspian Sea (CS). The equations were solved in the spherical coordinate system with a vertical array of pressure-sigma using a finite difference Method on a staggered modified Arakawa c grid. Simulations showed that there is an anticyclonic eddy over the deep water of South Caspian Basin (SCB), which extended from surface to subsurface and persist throughout the year. The model successfully produced the coastal current along the eastern coast of the Middle Caspian Basin (MCB) with a prevailing southward component, resulting in upwelling on these coasts to compensate the surface drift. The results indicate that the bottom topography has a key role in steering currents and generated a divergence in the surface Ekman layer which balanced by convergence in the frictional bottom Ekman layer in deepest areas of the CS.
 
An example of the microstructure of a duplex stainless steel (SAF2205): (bright: austenite, dark: ferrite). The structure shows 52 ± 2 wt% retained austenite. 
Subsea structures such as manifolds, line pipes and flow lines are important investments. Also because of the sensitivity of environmental issues, corrosion of these structures is of vital importance. Subsea corrosion management is different from on-shore and shallow water off-shore corrosion management in mainly three factors: materials, corrosion management practice and cathodic protection. There are important limitations in many aspects of these three factors that make them different from their “counterparts” in other industries. In this paper, some of these differences especially with regards to corrosion prediction softwares and associated design strategies are addressed and discussed.
 
Figure8. í µí°“ í µí¿í µí¿’ field in a meridional section. (a) λ=0, (b) λ=0.5, (c) λ=1 (solid and dash lines indicate spherical and ß plane coordinate results). 
Figure9. the solution to problems T1+T2+T3 for (a) λ=0, (b)λ=1 
Figure10-the solution to problems T 1 +T 2 +T 3 +T 4 for (a) λ=0, (b)λ=1 
the solution to problems T 0 +T 1 R 0 E-1 
The tropical Indian Ocean forms the major part of the largest warm pool on Earth, and its interaction with the atmosphere plays an important role in shaping climate on both regional and global scales. Three dimensional temperature and velocity fields are calculated analytically for an ocean forced by wind stress and surface heat flux. A basic thermal state involving a balance of lateral and vertical heat diffusion is assumed. The wind stress is chosen such that a tropical mass transport gyre is generated. An effect of nonlinear heat advection is calculated by a perturbation method. This circulation is closed through thin up and downwelling layers at the sides. Superimposed there is a barotropic wind driven circulation, with a transport field of the type described by Munk. The interior temperature field to the next order is affected not only by interior heat advection but by heat advection in the Ekman layer, in the up and downwelling layers and in the main western boundary current. We have compared Sepherical and Cartesian computational results.
 
Daily composite anomaly maps (1981-2010), the example for June 5, 2007. a) 500mb geopotential height, b) 500mb vertical wind speed, c) 850mb air temperature, d) 850mb relative humidity, e) sea level pressure, f) 1000mb wind speed.
Tropical cyclone frequency, monthly min and max TC events and median for each clusters
Variance and mean values of x and y along with the range of tropical cyclone genesis locations foreach cluster
Statistical characteristics of the tropical cyclones intensity for 5 clusters over the Arabian Sea during 1980-2013.
Cyclones are as one of the most dangerous meteorological phenomena of the tropical region that generate strong winds and heavy rainfall, impacting coastal regions. Behavior of tropical cyclone trajectories needs to be better understood in order to find predictable aspects of landfall potentially. This research aims to analyze the cyclone tracks statistically and then study of the associated meteorological effects of Gonu cyclone in June 2007 as an example. Using the cluster analysis (K-mean method) 5 principal clusters have been derived and spatial – temporal studies including the monthly variation of cyclone trajectories and their intensity and frequencies are performed. The 4th cluster indicated more spatial variability and expansion (4º-31ºN and 48.5º-78ºE). The second cluster showed the highest frequency with 349 events as well as the highest maximum intensity and standard deviation of 235.2km/h and 47.96km/h respectively. During 1-7 June 2007, the Gonu super cyclone traversed the Arabian Sea and reached the Iranian southern regions affecting the coastal infrastructures and communities. In this 7-day period the daily composite maps of different atmospheric levels showed that by intensifying of Gonu cyclone the axis of subtropical high pressures in the lower levels moved to the east and in the 500hp level they moved to the northward over the study region.
 
Tuned liquid column gas damper is a new type of energy absorber that can mitigate the vibrations of structures if their frequency and mass parameters are well tuned. Since this damper has recently been introduced and its behaviour in certain structures such as offshore oil platforms and wind turbines has already been tested, a suitable and accurate method is required to identify these optimal parameters. Therefore, considering the complexity of loads exerted on wind turbines in seas (wave and wind loads), in present study attempts are made to use a new artificial neural network approach to obtain optimal tuned liquid column–gas damper (TLCGD) parameters for mitigation of wind turbine vibrations. First fixed offshore wind turbines at various depths are designed in the MATLAB coding environment. After obtaining the stiffness, damping and mass matrices of the structures, the program enters the Simulink, and the wind turbine structure along with the TLCGD is exposed to different wave-wind load combinations within reasonable range of damper parameters. The neural network training is launched based on available statistical data of the offshore wind turbine with different heights as well as different frequency and mass ratios of the damper. According to this method, the percentage of errors found in the neural network outputs was negligible compared to the actual results obtained from the analysis in Simulink (even for inputs that stood outside the training range of the neural network). The mean error percentage, the standard deviation and the effective value of the neural network with actual values are below 10% for all three types of the structure. Finally, the method presented in this study can be used to obtain optimal parameters of the TLCGD for all kinds of offshore wind turbines at different depths of the sea, which leads to the optimal design of this damper to reduce the vibrations of wind turbines under wave and wind load pressures.
 
Despite the enormous military threats against the country's military facilities, especially the naval industry, correct understanding of the behavior of these structures in efficacy of explosion, analysis and design of this industry has been much importance than ever before. An important class of these threats, is underwater explosion and its effect on various structures, Floating or submerged. In this paper, the researcher first introduces the underwater explosion phenomena and theories that govern the propagation of fluid hydrodynamics, shock waves from the explosion and its interaction with floating and also submerged structures have been investigated. Finally, numerical studies (FEM) of the behavior of a super submarine subject to underwater explosion have been provided by ABAQUS software and some results have been obtained such as: response with different frequencies, the place of radiation boundary in interaction of water and construction, the effect of added mass and hydrodynamic pressure.
 
Three major approaches and their combination to crate hybrid method. 
The oil and gas pipelines are significant assets in Iran. However, these assets are subject to degradation from corrosion. Corrosion causes gradual thinning of the pipelines’ wall leading to leaks or bursts. Allowing a corroding pipeline to continue operation may lead to a finite risk of exceeding the limit state of burst. Codes of practice, such as Modified ASME B31G [1] and DNV F101 [3], among others, have developed relationships to determine the bursting pressure of corroded pipelines. The purpose of this paper is to develop, test, and illustrate a simple spreadsheet-based probabilistic procedure that can be used by practicing engineers to determine the Remaining Useful Life (RUL) of a corroding pipeline, following its first inspection. Modified ASME B31G and DNV F101 equations are used to illustrate this method. As new inspection data regarding the extent of corrosion becomes available, the results can be updated and a new probability of failure obtained. The calculated probability of failure is then compared with the target values to determine the remaining life. The approach is equally applicable to both onshore and offshore oil and gas pipelines.
 
Wave and current dynamic characteristics
Maximum dynamic responses of controlled (design 1 dampers) and uncontrolled jacket platform
Undesired oscillations of jacket platform may influence the structural functionality and sometimes fatigue occurs. The main objective of this research is to control wave-induced vibrations of fixed jacket platforms with the use of optimized shape memory alloys dampers. To model the hysteretic behavior of SMA elements and performing dynamic analysis an efficient isothermal idealized constitutive model is developed in this research and direct integration time history analysis is carried out. Dynamic responses of multi-degree of freedom system of jacket platform, with 90 m height and equipped with SMA dampers, is estimated and compared with the bare jacket. Furthermore, an optimization algorithm such as Ideal Gas Molecules Movements (IGMM) is implemented in this research to improve the efficiency of the dampers and minimize the deck displacements under the action of extreme wave. The results show that the optimized SMA dampers can improve the structural response by decreasing 47.5 percent of deck displacement, 56.5 percent of deck acceleration and finally 28 percent of base shear. In an SMA damper-equipped platform, reduced wave intensity will reduce the damper efficiency.
 
Drilling Operations are exposed to a variety of hazards, some of which may be location and activity dependent and each could pose different risk from different paths. Drilling operation may be vulnerable to hurricanes in one region and be exposed to Geohazards in another. However, there are other hazards, (e.g. corrosion, age degradation, poor maintenance), which equally affects every rig. Identifying what can go wrong and their likelihood and possible consequences provides insight into vulnerability of the operation and helps to generate mitigation options. Filtering and Ranking risk contributors enable to decide priorities and to focus on the most important risk contributors. This paper offers a framework to identify, assess, prioritize, and manage drilling risks, which includes: (1) a holistic approach to risk identification; (2) prioritization of a large number of risk influencing factors or risk scenarios; (3) structured elicitation of experts’ opinion and effective integration of experts judgment into qualitative and quantitative analyses to supplement limited data availability; (4) extreme and catastrophic event analysis; and (5) use of multi-objective framework to evaluate risk management priorities.
 
Area under investigation (Hadish watercourse) in Bandar Abbas 
shows the scatter diagram of water level derived from the model and those measured at field. The data presented in this figure are for the period of one month, from 18 th of March 2011 till the 17 th of April 2011, with the time step of 2 seconds. To show the good performance of the model, fitted trendline for the presented data in graph is provided. The equation represented the fitted trendline and its corresponded Rsquare are shown in the figure. Considering the fitted trendline equation, and the value of the R-square, it can be concluded that the water level data derived from this model can be used as boundary condition of the present model. Since the area under investigation is located near the Rajaaee Port, those water level time series measured at this station has been applied, for the western boundary condition. 
(A) Water level at Rajaaee Port, (B) water level at stations 1, 2, and 3 along the watercourse, (C) current velocity time series in the stations 1, 2, and 3 
Hadish watercourse located in the in south of Iran, is a seasonal channel of water which crosses through Bandar Abbas to reach to the Persian Gulf. This watercourse is faced with numerous environmental problems in regard with the pollution entrance. Huge amount of the urban and industrial sewages of the city are discharged into this watercourse. In this investigation, considering the discharge of 1.36 m3/s into this watercourse, according to the literatures, the procedure of emission of pollution in the area was modeled. For this purpose Delft3D software has been employed. The model has been calibrated and evaluated considering water level data from Rajaee Port. It was found that, the pollution mainly remains inside the watercourse which is due to the ebb dominance nature of the channel. The results of this research show that the discharging the sewage into this channel endangers not only the western coast of Bandar Abbas, but the health of the citizens.
 
A fundamental challenge facing security professionals is preventing loss; be that asset, production, or third-party losses. This is not dissimilar to what safety professionals have to face. Techniques and methodologies used by the safety professionals could potentially benefit the security experts. Physical security is about taking physical measures to protect personnel and prevent unauthorized access to installations, material, and documents, which also include protection against sabotage, willful damage, and theft. The characteristics of physical security controls include measures for deterrence, detection, delay, and responses aimed at risk mitigation and enhanced operational effectiveness. This paper outlines a systems engineering framework for implementing security goals, which are suitable for meeting the challenge of providing physical security for complex systems, which includes oil and gas facilities. The proposed framework builds security requirements into system requirements and moves it in parallel with the system development for the entire system’s life cycle; particularly during the concept and design phases. This is a top-down process for use by a multidisciplinary team of security, operations, and industry experts to identify and prevent the system from entering into vulnerable states which could lead to losses. This framework shifts the focus of the security analysis away from threats, being the immediate cause of losses, and focuses instead on the barriers, i.e. safeguards that prevent systems from entering into vulnerable states, which would allow an unfolding event to disrupt the system leading to loses. The need for such a method comes from the recent experience of the securing complex systems that combine a large amount of hardware, software hazardous materials, and control elements. The method takes advantage of systems engineering and encourages the use of goal-based security requirements instead of using a strict prescriptive approach that is common among security professionals. Using this framework helps both to identify threats associated with the system, as well as weak points within the system. This framework also encourages communication between the security professional, safety engineers, and system designers. This paper draws from the existing literature as listed in the references
 
In this study, the performance and efficiency of 12 ports in the Persian Gulf, Oman and Caspian seas in Iran is evaluated using data envelopment analysis (DEA) method. DEA allows comparing the efficiency in revenue generation of ports with different economies. Two different modeling approaches were presented in this study; based on relating earnings to port operational capability and activity, and based on land indicators, infrastructure, and equipment. The results of this study showed that most of the ports in the Persian Gulf region had a relative efficiency in the field of petroleum products. On the other hand, a significant difference was observed between the nominal capacity of acceptance of petroleum products of ports and the volume of oil product exchanges.
 
This study aims to investigate the capability of two common numerical methods, Homotopy Analysis Method (HAM) and Variational Iteration Method (VIM), and to suggest more efficient approximate solution method to the governing equations of nonlinear surface wave propagation in shallow water. To do so, semi-flat, moderate, and sharp slope of shore which are connected to an open ocean with a uniform depth are exposed to a solitary wave with initial wave height H=2 and stationary elevation d=20. Then, the surface elevation and velocity curves for these profiles are determined and compared by HAM and VIM. To verify the numerical modeling, two slopes i.e. semi-flat and moderate slope are considered and modeled in Flow-3D. Afterwards, the results of surface elevations are compared to each other by using correlation coefficient. The correlation coefficients for the slopes represent that the results coincide well. Ultimately, although the results of both methods are quite similar, using HAM is highly recommend rather than VIM since it makes solution procedure fast-converging and more abridged.
 
Rising dome due to expansion and upward migration of bubble 
Generating crater and lips after bubble collapse 
Primary wave generation and propagation due to underwater explosion (times in seconds, distances in meters)
a. Time evolution of dome shape and primary wave propagation with vertical velocity contours
The current manuscript presents the validation of Smoothed Particle Hydrodynamics (SPH) techniques for wave generation by underwater explosion, utilizing the so-called DualSPHysics numerical model. This numerical method is used to analyze generated waves which are initiated by man-made or natural explosions below free surface level of sea. In spite of the modeling limitations (e.g. absence of open boundary conditions), reasonable agreement is accomplished with predictions of the existing formula as well as experimental results. This proved that SPH techniques such as incorporated in DualSPHysics are becoming a suitable alternative to existing classical approaches to this particular water waves problem. It is also provided an inherently more accurate computational for the prediction of wave characteristics generated by underwater explosions.
 
Profile 1 (a) and Profile 2 (b) bed level change in calibration step (2006.02.20 to 2006.09.23)
Classification of Brier Skill Score by Van Rijn et al. (2003).
Overall result of Validation and Calibration steps
Among the numerous problems that decrease the capability of a harbor in the country, seasonal sedimentation is identified as a major problem for many fishery harbors. In 2007, Zarabad Fishery Harbor conditions were also identified as critical due to the large volume of sand accumulation and consequent closure of its entrance. Numerical modeling of coastal bed level change was implemented to provide insight into the typical response of the Zarabad beach to regular wave attacks, and to obtain an operational and validated model for the site. Advanced numerical models employed to predict coastal evolution at a variety of time and spatial scales usually include many free parameters that require calibration to the available field data. The XBeach numerical model was selected for its capacity to accurately model hydrodynamic and morphological processes over a two-dimensional domain. It comprises about 250 model settings that approximately 150 of these settings relate to physical and numerical Behavior and the other 100 are case-specific parameters. In this research, 11 parameters are adopted to optimize the model prediction efficiency for Zarabad Fishery Harbor area. For calibration and validation stages, two cross-shore profiles and two medium-term time periods are selected. The model showed great promise in predicting the evolution of cross-shore profiles under water, but as expected, the dry part results showed major errors. XBeach proved to be an operational tool to predict cross-shore profiles in the area, in such timescales. Although, more tests are needed to utilize the model in longer time periods with regard to the duration of simulations.
 
In this study, a numerical third-generation wave model was performed to generate 10 years (2000-2010) of wave hindcast in the Persian Gulf. The modified wind field data of European Center for Medium Range Weather Forecasts (ECMWF) and bathymetry data were used as the input data to model. In situ measurements and satellite-derived wave height were performed for model calibration, and validation the results. The results show that the overall accuracy is more than 80% over the whole Persian Gulf. Geographical Information System (GIS) was used to handle all datasets through a userfriendly software which provides required tools for data visualization and manipulation. Data management was carried on using the integration of Relational Database Management Systems (RDBMS) and GIS components.
 
The position of the field measuring stations and the position of the internal waves in the Persian Gulf
Landsat image showing the internal waves, (a) the internal waves around Farur Islands recorded on 07 April 2014; (b) the internal waves around the Larak Island on 25 May 2002.
SAR Satellite images of Sentinel-1 showing the internal waves, (a) the internal waves around Farsi Island recorded on 20 August 2015; (b) the internal waves around the Khark Island on 29 March 2015.
In this research, density, temperature and salinity fields were investigated in different seasons using observational data of ROPME Marine Cruise in the Persian Gulf (PG). Based on in-situ measurements, areas with density stratification were identified. Having analyzed Landsat and SAR satellite images, internal waves (IW) were detected in different regions of the Persian Gulf and more frequently in the eastern part of the PG related to seawater stratification. Based on analysis of satellite images, it is shown that the length of internal waves crest detected in the north-eastern part of Al-Zhahirah (Qatar) was more than 120 km; while it’s in range of 5 to 20 km in the south and east of Larak Island, 15 to 40 km in the north-east of Abu Musa Island, and 3 to 65 km in the south-east and south of Hondurabi Island. Moreover, IWs with shorter crest’s wide were recognized near Lavan, Siri, Farur, Halul, Khark Islands and Bandar Lengeh, as well. In addition, studying satellite images in the above mentioned areas for a longer time period from 2000 to 2017 showed that IWs mostly occur in the eastern part of the PG in summer and disappear in other seasons.
 
A weakly compressible SPH (WCSPH) scheme has been developed to simulate interaction between waves and rigid bodies. The developed WCSPH scheme is improved by applying a modified equation to calculate the wave-structure interaction, in order to increase its accuracy. The effects of relative fluid/solid particles’ acceleration are considered in the modified equation. To evaluate the efficiency of developed model, the dynamics of structural movements and related pressure fields are investigated for several test cases and the results are compared with the experimental data. It seems that the modified algorithm is able to improve the accuracy of simulated wave-structure interactions.
 
The basic ideas of using SA in marine operations.
Steps of assuring safe marine operation
Endsley's Model of Situation Awareness  Level 1 -Perception: Perception of environmental cues is fundamental to situation awareness. Without the basic perception of important information, the odds of forming an incorrect picture of the situation increase dramatically.  Level 2 -Comprehension: The notion of situation awareness also encompasses how people combine, interpret, store and retain information. Thus, it includes more than just perceiving or attending to information; it also involves the integration (fusion) of multiple pieces of information and a determination of their relevance to the person's goals and objectives.  Level 3 -Projection: At the highest level of situation awareness, the ability to forecast future events and dynamics is required. This ability to project from current events and dynamics to anticipate future events (and their implications) constitutes the basis for operationally-useful decision making, e.g. knowing that a threat to an aircraft is current and from a certain location, allows fighter pilots or military commanders to project that the aircraft is likely to be attacked in a given manner.
Perceiving the environment and sense-making
MDA Competencies
Safety in marine operations primarily depends on forward-planning and people being aware of their surroundings and managing the presence of others in the same arena at the same time. Marine operations must contend with challenging environments and hazards that require greater domain awareness; especially when many operators from different organisations are working in the same area. Being aware of what is going on around you in a marine domain, is termed Marine Domain Awareness (MDA), which involves the perception and understanding of environmental factors, their meaning and effects, and foreseeing their likely status and impact in the near future. This paper applies Situational Awareness (SA) concepts to the safety of marine operations and proposes a model for developing an information exchange system to enhance marine operational safety. The proposed model enhances MDA and can help in developing procedures and training programs to promote domain awareness.
 
Top-cited authors
Sirous Yasseri
  • Brunel University London
H. Bahai
  • Brunel University London
Danial Ghaderi
  • Hormozgan University
Maryam Rahbani
  • Hormozgan University
Abdolrahim Taheri
  • Petroleum University of Technology