On the History, Science, and Technology Included in the Moody Diagram

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Marc LaViolette
Keyword(s):  
Pipe Flow ◽  
Flow Problem ◽  
Science And Technology ◽  
Large Body ◽  
Historical Review ◽  
Traditional Use ◽  
Flow Measurements ◽  
Dimensionless Groups ◽  
Moody Diagram

This paper is a historical review of the science, both experimental and theoretical, behind the iconic Moody diagram used to avoid tedious iterations choosing pumps and pipes. The large body of historical pipe flow measurements and the choice of dimensionless groups and the Buckingham-Π theorem are also discussed. The traditional use of the Moody diagram to solve common pipe flow problem is discussed. Alternatives to the Moody diagram from the literature and novel ones presented here are shown to produce a solution without iteration for any type of pipe loss problem.

Comparison of a Nonlinear k-ε Turbulence Closure Model With Stress Transport Models

1993 ◽  
Author(s):  
Muhammad A. R. Sharif ◽  
Yat-Kit E. Wong
Keyword(s):  
Pipe Flow ◽  
Flow Problem ◽  
Swirling Flow ◽  
Transport Model ◽  
Turbulent Pipe Flow ◽  
Turbulence Closure ◽  
Closure Model ◽  
Transport Models ◽  
Mean Velocity ◽  
Turbulence Closure Model

Abstract The performance of a nonlinear k-ϵ turbulence closure model (NKEM), in the prediction of isothermal incompressible turbulent flows, is compared with that of the stress transport models such as the differential Reynolds stress transport model (RSTM) and the algebraic stress transport model (ASTM). Fully developed turbulent pipe flow and confined turbulent swirling flow with a central non-swirling jet are numerically predicted using the Marker and Cell (MAC) finite difference method. Comparison of the prediction with the experiment show that all three models perform reasonably well for the pipe flow problem. For the swirling flow problem, the RSTM and ASTM is superior than the NKEM. RSTM and ASTM provide good agreement with measured mean velocity profiles. However, the turbulent stresses are over- or under-predicted. NKEM performs badly in prediction of mean velocity as well as the turbulent stresses.

Image-Based Measurements of Myocardial Blood Flow

2015 ◽  
Author(s):  
Heinrich R. Schelbert
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Structural Changes ◽  
Large Body ◽  
Treatment Strategies ◽  
Flow Measurements ◽  
Time Activity ◽  
Flow Reserve ◽  
Coronary Stenoses ◽  
Functional Consequences

Image-based measurements of myocardial blood flow afford the assessment of coronary circulatory function. They reflect functional consequences of coronary stenoses, diffuse epicardial vessel disease and microvascular dysfunction and structural changes and thus provide a measure of the total ischemic burden. Measured flows contain therefore clinically important predictive information. Fundamental to flow measurements are the tissue tracer kinetics, their description through tracer kinetic models, high spatial and temporal resolution imaging devices and accurate extraction of radiotracer tissue concentrations from dynamically acquired images for estimating true flows from the tissue time activity curves. A large body of literature on measurements of myocardial blood flow exists for defining in humans normal values for flow at baseline and during hyperemic stress as well as for the myocardial flow reserve. The role of PET for flow measurements has been well established; initial results with modern SPECT devices are encouraging. Responses of myocardial blood flow to specific challenges like pharmacologic vasodilation and to sympathetic stimulation can uncover functional consequences of focal epicardial coronary stenoses, of conduit vessel disturbances and disease and impairments of microvascular function. Apart from risk stratification, flow measurements may allow detection of early preclinical disease, influence treatment strategies and identify therapy responses.

Pipe Flow Measurements of a Transparent Non-Newtonian Slurry

1989 ◽  
Vol 111 (3) ◽  
pp. 331-336 ◽  
Author(s):  
J. T. Park ◽  
R. J. Mannheimer ◽  
T. A. Grimley ◽  
T. B. Morrow
Keyword(s):  
Velocity Profile ◽  
Newtonian Fluid ◽  
Power Law ◽  
Pipe Flow ◽  
Large Scale ◽  
Longitudinal Velocity ◽  
Tangential Velocity ◽  
Turbulent Pipe Flow ◽  
Laser Doppler Velocimeter ◽  
Flow Measurements

An experimental description of the flow structure of non-Newtonian slurries in the laminar, transitional, and full turbulent pipe flow regimes is the primary objective of this research. Experiments were conducted in a large-scale pipe slurry flow facility with an inside pipe diameter of 51 mm. The transparent slurry formulated for these experiments from silica, mineral oil, and Stoddard solvent exhibited a yield-power-law behavior from concentric-cylinder viscometer measurements. The velocity profile for laminar flow from laser Doppler velocimeter (LDV) measurements had a central plug flow region, and it was in agreement with theory. The range of the transition region was narrower than that for a Newtonian fluid. The mean velocity profile for turbulent flow was close to a 1/7 power-law velocity profile. The rms longitudinal velocity profile was also similar to a classical turbulent pipe flow experiment for a Newtonian fluid; however, the rms tangential velocity profile was significantly different.

An Alternative (Preferable) Friction Factor

2006 ◽  
Author(s):  
Richard A. Gaggioli
Keyword(s):  
Reynolds Number ◽  
Friction Factor ◽  
Pipe Flow ◽  
Incompressible Flows ◽  
Flow Regimes ◽  
Relative Roughness ◽  
Curve Fit ◽  
Moody Diagram ◽  
Approximate Formulas

An alternative to the traditional friction factor for pipe flow is presented (φ = [R]f). For incompressible flows, the correlation of this new friction factor with Reynolds Number [R] and Relative Roughness [ε] is presented graphically, and appears much simpler and more intuitive than the Moody Diagram (or other equivalents). Moreover, relatively simple curve-fit formulas for representing φ explicitly as a function of R and ε are presented for various flow regimes, along with measures of error associated with these approximate formulas.

An Alternative Approach for Teaching Turbulent Flow

2007 ◽  
Author(s):  
Ahmad Fakheri
Keyword(s):  
Turbulent Flow ◽  
Pipe Flow ◽  
Numerical Solutions ◽  
Experimental Results ◽  
Mixing Length ◽  
Law Of The Wall ◽  
Alternative Approach ◽  
Logarithmic Law ◽  
Basic Concepts ◽  
Moody Diagram

Teaching of turbulence in undergraduate and early graduate level fluid mechanics and heat transfer courses is a difficult undertaking. The approach taken in typical texts requires the students to accept a number of basic concepts without much quantitative justifications. This paper presents an alternative approach, one in which most of the salient features of the turbulent flow are derived by using numerical solutions and experimental results, as opposed to simply having them presented. In this approach, Prandtl’s mixing length model is used to obtain the velocity distribution for fully developed pipe flow. By comparing the numerical calculations with the experimental results, students determine the value of κ that best fits the experimental data on their own. In addition, deficiency of the mixing length in the transition region is shown. It is also shown that other models like Van Driest’s do a better job. The Logarithmic Law of the wall as well as 7th power law are also proven. The different models are used to determine the friction factor for pipe flow and the results are compared with the values obtained from the Moody diagram.

Making the Pacific, Making Japanese-U.S. Relations

2019 ◽  
Vol 88 (4) ◽  
pp. 511-523
Author(s):  
Martin Collins
Keyword(s):  
Twentieth Century ◽  
Science And Technology ◽  
Critical Role ◽  
Historical Review ◽  
Nation State ◽  
Special Issue ◽  
Modern Project ◽  
The Pacific ◽  
Interpretive Frame ◽  
Historical Accounts

This special issue of Pacific Historical Review, “Making the Pacific, Making Japanese-U.S. Relations: Science and Technology as Historical Agents in the Twentieth Century,” is guest edited by Martin Collins and Teasel Muir-Harmony. The special issue gives prominence to science and technology as sources of agency inextricably bound to the modern project—and thus bound to another expression of the modern, the nation state and its interrelation with other states. In the modern context, scientific and technical knowledge, practices, and things are fundamental to composing more robust historical accounts, including accounts of the nation state. This interpretive frame is vital in understanding the Japan-U.S. relationship in the twentieth century and the critical role of the Pacific Ocean therein. The special issue includes a preface from Marc S. Rodriguez, this introduction by Martin Collins, and articles by Daqing Yang on wireless telegraphy, Chihyung Jeon on postwar trans-Pacific air flight, Teasel Muir-Harmony on the U.S. spaceflight display at the 1970 Osaka World Exposition, and Colin Garvey on the international race to develop artificial intelligence.

scholarly journals Alfabetização científica e/ou letramento científico: reflexões sobre o Ensino de Ciências

2021 ◽  
Vol 5 (5) ◽  
pp. 1299-1312
Author(s):  
Francisco Jucivanio Felix de Sousa ◽  
Lígia Vieira da Silva Cavalcante ◽  
José Claudio Del Pino
Keyword(s):  
Qualitative Research ◽  
Science Education ◽  
Everyday Life ◽  
Science Teaching ◽  
Scientific Literacy ◽  
Social Transformation ◽  
Basic Education ◽  
Science And Technology ◽  
Historical Review

The article presents the results of a qualitative research, from exploratory nature, by means of bibliographic procedure whose point is to promote the understanding of Scientific Literacy, translated to portuguese as "Alfabetização Científica" (AC), and Scientific Literacy, translated to portuguese as "Letramento Científico (LC) and their role and importance in science teaching in basic education. The concepts of AC and LC are presented, followed by a historical review of the science teaching in the process of formal leaning, highlighting the several adaptations this teaching has suffered until its newest structuring, according to the documents that standardize Brazilian education. Some incursions are carried out to reflect on the need of integral formation of learners, with criticality and ethics, through activities that relate different areas and spheres of life in society. It is concluded that, in order to reach such an education, it is necessary a teaching which is beyond the assimilation of concepts and formulas in the scope of science education, seeking the understanding of concepts and applications in everyday life, in order to a social transformation as of science and technology.

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