Quinn’s Law of Fluid Dynamics, Supplement #4 Taking the Mystery out of Permeability Measurements in Porous Media
Issue:
Volume 8, Issue 1, June 2022
Pages:
1-15
Received:
18 February 2022
Accepted:
15 March 2022
Published:
29 March 2022
DOI:
10.11648/j.fm.20220801.11
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Abstract: The published literature on porous media is filled with erroneous and contradicting assertions relating to measurements of permeability. In this paper, we present a new and novel approach to remedy this situation, by demonstrating a standard methodology using a new fluid flow model. This model is different from any model currently in use and provides a unique analytical solution for the input variables underlying packed beds containing porous media of discrete particles, be they porous or nonporous in nature. The model is based upon the fundamental principles of the physics involved in fluid flow through packed beds which includes, amongst other things, a unique normalization coefficient which acts as an exchange rate between viscous and kinetic contributions, on the one hand, and certification, via a built-in methodology, on the other hand, that the Laws of Continuity are always adhered to. In addition, the model is thorough with respect to both wall effect and fluid path tortuosity, which means that a new Law of Fluid Flow in closed conduits is identified as a straight-line relationship between viscous normalized pressure drop, on one side of the equality sign, and normalized fluid flow, on the other side of the equality sign. The model is based upon the discovery of a new vector entity, np, the number of particles of a given diameter, say dp, present in a packed conduit and, therefore, applies seamlessly to both packed and empty conduits which, in turn, enables its validation over 10 orders of magnitude of the modified Reynolds number. This vector has never been identified heretofore and is valid for all particle porosities which include fully porous particles, i.e., particles of free space and, hence, empty conduits are considered as packed conduits with particles of free space. The vector np specifies, simultaneously, the matched set of a given value for the particle diameter dp and the external porosity, ε0, in any packed conduit under study, much the same as a velocity vector specifies, simultaneously, the matched set of a given value for the speed and direction of a projectile or moving object. The model is explained herein and applied to a number of experimental studies, demonstrating a standardized methodology which guarantees an exact correlation between measured and calculated values in the permeability relationship, when reporting on actual experiments in closed conduits.
Abstract: The published literature on porous media is filled with erroneous and contradicting assertions relating to measurements of permeability. In this paper, we present a new and novel approach to remedy this situation, by demonstrating a standard methodology using a new fluid flow model. This model is different from any model currently in use and provid...
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Numerical Investigation on the Wind-Excited Dynamic Response of Span-Wire Traffic Signal System
Zeda Yin,
Manuel Matus,
Ioannis Zisis,
Arturo Segundo Leon
Issue:
Volume 8, Issue 1, June 2022
Pages:
16-26
Received:
4 April 2022
Accepted:
27 April 2022
Published:
10 May 2022
DOI:
10.11648/j.fm.20220801.12
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Abstract: The performance of span-wire mounted traffic signal systems can be significantly affected by extreme wind events. Multiple mechanical failure cases of this type of traffic signal systems occurred in Florida in the past hurricane seasons, resulting in unsafe traffic conditions. For better analysis the force on structure, this paper presents the results of the numerical investigation on the wind-induced dynamic response of the span-wire traffic signal system. The numerical simulation is conducted for a full-scale test, and the geometry is generated based on the 12 inch diameter manufacturer design. Wind speeds has been chosen as the major variable, ranged from 30 to 75 mph, in this numerical simulation. The current numerical simulation results have been compared with the pervious experimental results conducted in Florida International University Wall of Wind facility, and the comparison shows a great agreement. Some major findings, for instance, inclination and RMS acceleration of signal, the tension force on wire, along with the flow filed have been detailed discussed in this paper. This paper found that the wire tension increase with the increase of wind speed. Periodic eddy circulations were found and discussed in low wind speed (30-45 mph). The traffic signals are subject to large inclinations, motions, and external force loads under high upcoming wind speeds (75 mph).
Abstract: The performance of span-wire mounted traffic signal systems can be significantly affected by extreme wind events. Multiple mechanical failure cases of this type of traffic signal systems occurred in Florida in the past hurricane seasons, resulting in unsafe traffic conditions. For better analysis the force on structure, this paper presents the resu...
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