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MIC Investigation of Stainless Steel Seal Ring Corrosion Failure in a Floating Production Storage and Offloading (FPSO) Vessel
Published in Richard B. Eckert, Torben Lund Skovhus, Failure Analysis of Microbiologically Influenced Corrosion, 2021
L.L. Machuca, T. Pojtanabuntoeng, S. Salgar-Chaparro, E. Suarez, B. Kinsella, A. Darwin
In the oil and gas industry, a hydrostatic pressure test is normally performed after installation of pipelines and all piping systems to verify pressure equipment does not leak and ensure they are fit for service. This quality control measure allows inspecting the strength and integrity of pipelines, vessels, and tanks before they are commissioned. The pressure of the hydrostatic test is commonly set above the design pressure (usually 125% of the Maximum Allowable Operating Pressure – MAOP), providing a safety margin against design tolerance and defect growth during the service life of assets (Machuca 2017). Besides the inspection of new systems, hydrotesting is also performed in aged systems to determine their integrity, to confirm MAOP, and to maximize their use. It has been reported that this method can reduce unnecessary replacement of aged pipelines, helping to extend their lives and avoiding repair and replacement costs (Lenhoff 1994).
Hydrostatics and Hydraulics
Published in W. David Yates, Safety Professional’s Reference and Study Guide, 2020
In preparing for the Associate Safety Professional/Certified Safety Professional examinations, the candidate must have a fundamental understanding of hydraulics and hydrostatics. In the everyday “safety world,” you may not automatically understand the importance of having this understanding. However, if you just take a look around, you will see that having this knowledge can make a difference in the safety and health of employees. A question you may be asking yourself is “What are hydrostatics and hydraulics?” Hydrostatics, also known as fluid statics, is the science of fluids at rest and is a subfield within fluid mechanics. It embraces the study of the conditions under which fluids are at rest in stable equilibrium. Hydrostatics is about the pressures exerted by a fluid at rest. Any fluid is meant, not just water.1 The use of fluid to do work is called hydraulics, and the science of fluids in motion is fluid dynamics. Hydraulics is a topic in applied science and engineering dealing with the mechanical properties of liquids. Hydraulics is used for the generation, control, and transmission of power by the use of pressurized liquids.
Fluid Statics
Published in Ahlam I. Shalaby, Fluid Mechanics for Civil and Environmental Engineers, 2018
The linear increase of the hydrostatic pressure, p in a fluid with depth, z (hydrostatic pressure equation, (dp/dz) = γ) results in the existence of an upward vertical force called the buoyant force, FB. One may observe the existence of the buoyant force, FB when a body of any given density, ρ is submerged in the fluid. The buoyant force, FB tends to lift the body upward. Thus, buoyancy or the buoyant force, FB is defined as the hydrostatic force exerted by the fluid on the surface of a submerged body that is either floating or suspended (naturally or manually) in the fluid (as opposed to a submerged body that is anchored, as in Section 2.4). The weight, FG = Mg = W = γV of a submerged floating or suspended body (object) appears to decrease due to the buoyant force, FB. While the magnitude of the buoyant force, FB can be significant when the fluid is a liquid, it is negligible in most applications when the fluid is a gas. The Archimedes principle provides the basis for the determination of the buoyant force, FB and is stated as follows: the weight, W of a submerged body is reduced by an amount equal to the buoyant force, FB, which has a magnitude equal to the weight of the fluid displaced by the body and acts vertically upward through the centroid of the displaced volume.
Development of fragility functions for rigid-frame bridges subjected to tsunami-induced hydrodynamic forces
Published in Structure and Infrastructure Engineering, 2022
Ismail M. I. Qeshta, M. Javad Hashemi, M. Reza Hashemi, Rebecca J. Gravina, Sujeeva Setunge
The tsunami-induced forces generated on bridges are mainly classified as: (1) hydrodynamic forces induced by the steady-state flows, (2) hydrostatic forces due to partial or total submergence (3) highly transient impact forces. The hydrostatic force is a force under the static condition in which the pressure force balances with the gravitational body force. The integration of the vertical component of the hydrostatic pressure produces a net upward force that is called the buoyant forces. The buoyant forces are a function of the displaced volume of water by the bridge, but their magnitude can be increased due to the presence of air entrapment in the superstructure (Azadbakht & Yim, 2016; Seiffert, Ertekin, & Robertson, 2015; Xu, Cai, & Chen, 2017). These loading were not considered in this study as for the case of rigid-frame bridges it is assumed that the foundation capacity of piers, pier-to-deck connection strength, and the axial tensile capacity of piers are larger than the uplift forces.
Finite element simulation for multiphase fluids with different densities using an energy-law-preserving method
Published in Engineering Applications of Computational Fluid Mechanics, 2020
The model for multiphase fluids with various densities proposed by Abels et al. (2012) can be written as: and the boundary conditions as , , and . Here, is velocity vector and , are velocity components in , directions. In particular, denotes the order parameter for defining different phases (: fluid A; : fluid B). denotes the hydrostatic pressure. is the viscous part of the stress tensor. is the fluid dynamic viscosity. is the chemical potential. is the physical surface tensor. is phenomenological mobility coefficient. is the interface thickness. The total mass density of the mixture, , can be expressed as . , denote the mass flux due to the various densities (Lowengrub & Truskinovsky, 1998) and double-well potential, respectively. represents acceleration due to gravity.