Pressure Gradient Research Papers - Academia.edu (original) (raw)

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The aim of the methods described is to calculate the properties of turbulent reactive flow fields. At each point in the flow field, a complete statistical description of the state of the fluid is provided by the velocity-composition joint pdf. This is the joint probability density function (pdf) of the three components of velocity and of the composition variables (species mass fractions and enthalpy). The principal method described is to solve a modelled transport equation for the velocity-composition joint pdf. For a variable-density flow with arbitrarily complex and nonlinear reactions, it is remarkable that in this equation the effects of convection, reaction, body forces and the mean pressure gradient appear exactly and so do not have to be modelled. Even though the joint pdf is a function of many independent variables, its transport equation can be solved by a Monte Carlo method for the inhomogeneous flows of practical interest. A second method that is described briefly is to solve a modelled transport equation for the composition joint pdf.The objective of the paper is to provide a comprehensive and understandable of the theoretical foundations of the pdf approach.

- by Faruk Civan
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- Petroleum Science and Engineering, Pressure Gradient
- by Shahab Ayatollahi
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- Two Phase Flow, Heat Transfer, Computer Simulation, Theory and Practice

This thesis begins with a study of the origin of cosmological fluctuations with special attention to those cases in which the non-Gaussian correlation functions are large. The analysis shows that perturbations from an almost massless auxiliary field generically produce large values of the non-linear parameter f_NL. The effects of including non-Gaussian correlation functions in the statistics of cosmological structure are explored by constructing a non-Gaussian probability distribution function (PDF). Such PDF is derived for the comoving curvature perturbation from first principles in the context of quantum field theory, with n-point correlation functions as the only input. The non-Gaussian PDF is then used to explore two important problems in the physics of primordial black holes (PBHs): First, to compute non-Gaussian corrections to the number of PBHs generated from the primordial curvature fluctuations. The second application concerns new cosmological observables. The formation of PBHs is known to depend on two main physical characteristics: the strength of the gravitational field produced by the initial curvature inhomogeneity and the pressure gradient at the edge of the curvature configuration. We account for the probability of finding these configurations by using two parameters: The amplitude of the inhomogeneity and its second radial derivative, evaluated at the centre of the configuration. The implications of the derived probability for the fraction of mass in the universe in the form of PBHs are discussed.

- by Juan Hidalgo
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- Quantum Field Theory, Primordial Black Hole, Pressure Gradient, Perturbation Theory
- by MOHAMMED I D R I S S AHMED
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- Engineering, Turbulence, High Pressure, Aerodynamics
- by Sanjeev Sanghi
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- Mechanical Engineering, Applied Mathematics, Mesh generation, Comparative Study
- by Oscar Rodriguez
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- Engineering, Multiphase Flow, Two Phase Flow, Pipe Flow
- by Daniel Tondeur
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- Chemical Engineering, Pressure Drop, Flow Rate, Pressure Gradient
- by Bruce Yardley
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- Geology, Geochemistry, Arsenic, High Temperature
- by Jing-jia Luo
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- Science, Multidisciplinary, Indian summer monsoon, High Resolution
- by John Kim
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- Engineering, Fluid Mechanics, Direct Numerical Simulation, Mathematical Sciences
- by Thomas Hahn
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- Engineering, Composites, Mathematical Model, Spatial Variation
- by Haakon Fossen
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- Geology, Geophysics, Fluid flow, Pressure Gradient
- by Samantha J Hughes
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- Environmental Management, Environmental Monitoring, Rivers, Multidisciplinary
- by Senay Tewel-de
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- Pharmacology, Biochemistry, Bioinformatics, Evolutionary Biology
- by Philippe Schmitz and +1
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- Engineering, Crossflow Filtration, Fluid Dynamics, Desalination

The theory-based closure relations for the wall and interfacial shear stresses obtained previously for laminar stratified flow, are extended to be applicable also to turbulent flows in either or both of the phases. The closure relations are formulated in terms of the single-phase-based expressions, which are augmented by two-phase interaction factors, due to the flow of the two phases in the same channel. These closure relations, which are valid for smooth stratified flow in horizontal or inclined pipes, were used as a platform for introducing necessary empirical corrections required in the stratified wavy flow regime. Based on experimental data available from the literature, new empirical correlations for the wave effect on the interface curvature, on the interfacial shear and on the liquid wall shear were obtained. The predictions of the two-fluid model for the pressure gradient and holdup are tested against extensive data bank and some analytical solutions for stratified flows. T...

- by Amos Ullmann
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- Engineering, Multiphase Flow, Closure, Turbulent Flow
- by Michael Spall
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- Oceanography, Sea surface temperature, Atmospheric sciences, Air-Sea Interaction
- by Dharmendra Tripathi
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- Applied Mathematics, Wave propagation, Mittag-Leffler Function, Adomian decomposition method
- by stephen cowin and +1
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- Mechanical Engineering, Biomedical Engineering, Biomechanics, Rheology
- by Thomas Alrutz
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- Engineering, Computational Physics, Turbulence, Aerodynamics
- by Ayman Fouad
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- Nonparametric Statistics, Treatment Outcome, Egypt, Risk assessment
- by Kris Piessens and +1
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- Engineering, Earth Sciences, Climate Change, Renewable Energy
- by Soumyajit Mukherjee
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- Earth Sciences, Partial Melting, Tibetan Plateau, Shear Zone
- by Lucia Pappalardo
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- Geology, Geochemistry, Partition Coefficient, Magma Chamber
- by R. Arabjamaloei
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- Enhanced Oil Recovery, Neural Network, Compressive Strength, Pore Pressure
- by Alessandro Paglianti
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- Chemical Engineering, Slug Flow, Fluid flow, Mathematical Model
- by Menachem Elimelech
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- Engineering, Membrane Science, Carbon Dioxide, Power Generation
- by gerson santos
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- Engineering, Building Energy Simulation, Energy Consumption, Heat and Mass Transfer
- by J. Wissink
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- Engineering, Boundary Layer, Low Pressure Boiler, Pressure Gradient
- by Elin Skurtveit and +1
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- Geology, Structural Geology, Structural, Power Law
- by Anthony Chiang
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- Materials Engineering, Chemical Engineering, Adsorption, Cycle Time
- by Barry D. Keim
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- Engineering, Earth Sciences, Air Quality, Sea Breeze
- by Noam Alperin
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- Mechanical Engineering, Biomechanical Engineering, Biomedical Engineering, Computational Fluid Dynamics
- by Anoop Chengara
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- Engineering, Physical sciences, Long Range, Interfacial Tension
- by Philippe Guillen and +1
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- Engineering, Fluid Mechanics, Mesh generation, Strain Rate
- by Thomas Dunne and +1
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- Morphological evolution, Fluvial Geomorphology, Multidisciplinary, Sediment transport
- by Noor Afzal
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- Environmental Engineering, Civil Engineering, Cross Section, Hydraulic
- by Claude Basdevant
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- Applied Mathematics, Numerical Simulation, Classical Physics, Boundary Layer
- by Michael Shur
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- Engineering, Boundary Layer, Negative Skin Friction, Compressible Flow
- by John Machell and +1
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- Distributed System, Neural Network, Information Fusion, Data Fusion
- by Mustafa Onur
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- Geology, Geophysics, Production, Performance
- by Orhan aydın
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- Engineering, Economics, Temperature Distribution, Applied Energy
- by Mani Vannan
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- Japan, Humans, Europe, United States
- by Didier PONT
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- Design Research, Biological Sciences, Ecological Indicator, Environmental Sciences
- by James Boles
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- Geology, Geochemistry, Geophysics, Kinetics

Pressure Gradient Research Papers - Academia.edu (original) (raw)

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