How to abbreviate Weissenberg Number? Read what you need to know about our industry portal chemeurope.com. Find out how LUMITOS supports you with online marketing. Therefore the exact definition of all non dimensional numbers should be given as well as the number itself. Deborah Number. Just as the Reynolds number is a convenient measure of the ratio of inertial to viscous forces, so the Weissenberg number can be viewed as a ratio of elastic to viscous effects. In contrast, the Deborah number should be used to describe flows with a non-constant stretch history, physically represents the rate at which elastic energy is stored or released Als „Beobachtungszeit“ kann z. Toward a solution to the high Weissenberg number problem David Trebotich∗1 1 Center for Applied Scientific Computing, Lawrence Livermore National Laboratory, P.O. Debi Weissenberg currently lives in Cumming, GA; in the past Debi has also lived in Roswell GA and Alpharetta GA. Other names that Debi uses includes Debi L Hill, Deborah Leigh Weissenberg, Deborah Leigh Hill, Deborah L Weissenberg and Debi L Weissenberg. We present results of a numerical study of high Weissenberg number flowsusing themethod of Trebotich, Colellaand Miller, J. Comput. time for the deformation process is infinite and the Deborah number is therefore zero for such flows regardless of the relaxation time of the material. B. das Inverse einer … Today, 17, pp 62 (1964) Another dimensionless number sometimes used in the study of viscoelastic flow is the Weissenberg number. … Rheology is generally lacking in dimensionless numbers except for two - the Deborah Number and the Weissenberg number. Famous quotes containing the words deborah and/or number: “ Q: What would have made a family and career easier for you? It was my first job righ... One of the big corn processors from here in the Midwest is suggesting that isosorbide could be used as a replacement for bisphenol A (BPA) ... A plastic wheel rim, made from BASF's Ultramid (nylon) with long glass fiber reinforcement: While the engineers in the video make some ... (c) Copyright 2006 - 2015, John A. Spevacek, Free Access to Research in the Polymer Literature, Fundamentals of Dynamic Mechanical Analysis, Significant Acceleration of a UV-Cured Coating (Part 1 of 2), Significant Acceleration of a UV-Cured Coating (Part 2 of 2), Nanoemulsions for Dissolving Polymer Films, The Wall Street Journal and "Glass Transition", 10 Things I Wish I Would Have Learned In School, A New Option for Accessing Research - Renting. In contrast, the Deborah number should be … Deborah number D = time of relaxation/time of observation. dict.cc English-German Dictionary: Translation for Weissenberg number It is named after Karl Weissenberg. M.A. In some aspects, the problem of high Weissenberg number … Box 808, L-560, Livermore, CA 94551, USA. The Weissenberg number indicates the degree of anisotropy or orientation generated by the deformation, and is appropriate to describe flows with a constant stretch history, such as simple shear. As for the numbers, the Deborah number is ratio of the relaxation time of the polymer divided by the observation time. (1965), there are important differences in more complex flows that are associated with the unsteadiness (in either the Eulerian or Lagrangian sense) of the process, and these two dimensionless measures of viscoelastic effects are typically … The Deborah number (De) is a dimensionless number, often used in rheology to characterize the fluidity of materials under specific flow conditions. The deformation rate however, does appear directly in the Weissenberg number, … 2 (1993) “ I think, for the rest of my life, I shall refrain from looking up things. Engineers have always loved dimensionless numbers [*], groups of variables where the units cancel leaving them free from the chosen system of measurement. Reiner named this dimensionless number after the prophete Deborah who, in the Book of Judges, proclaimedThe mountains flowed before the lord. Deborah number - Wikipedia The Weissenberg effect was named after him, as was the Weissenberg number. Deborah number - Wikipedia The Weissenberg effect was named after him, as was the Weissenberg number. Mostly finite-element … We present results of a numerical study of high Weissenberg number flowsusing themethod of Trebotich, Colellaand Miller, The Weissenberg number indicates the degree of anisotropy or orientation generated by the deformation, is appropriate to describe flows with a constant stretch history, such as simple shear. Alves, R.J. Poole. The Deborah number D e is defined as the ratio of characteristic time of the fluid to the time scale of the process. It quantifies the observation that given enough time even a solid-like material might flow, or a fluid-like material can act solid when it is deformed rapidly enough. On the other hand, if the time of relaxation of the ma-terial is larger than your … In contrast, the Deborah number should be … Despite their different origins, and the fact that they quantify different effects, they are frequently used as synonyms. Since their introduction to the literature nearly fifty years ago the Deborah and Weissenberg numbers have proved invaluable for rheologists in quantifying viscoelastic effects. While Wi is similar to the Deborah number and is often confused with it in technical literature, they have different physical interpretations. 2 ways to abbreviate Weissenberg Number updated 2020. CrossRef View Record in Scopus Google Scholar. While Wi similar to the Deborah number, and is often confused with it in technical literature, they have different physical interpretations. Computational rheology started in the early 1970s. ↑ M. Reiner (1964) Physics Today, Band, 17, Nr. © 1997-2021 LUMITOS AG, All rights reserved, https://www.chemeurope.com/en/encyclopedia/Weissenberg_number.html, Your browser is not current. Categories: Fluid mechanics | Non-Newtonian fluids. Moreover, a non-monotonic relation between shear stress and … The most popular abbreviation for Weissenberg Number is: Wi Planar contraction flows of non-Newtonian fluids with integral constitutive models are studied to investigate the problem of numerical breakdown at high Weissenberg or Debrorah numbers. Everything flows, but only the macromolecules are worth the time. Tapan,The link has been fixed. Skip to main content Accessibility help … The Weissenberg number indicates the degree of anisotropy or orientation generated by the deformation, and is appropriate to describe flows with a constant stretch history, such as simple shear. The greater the Deborah number, the more solid the material; the smaller the Deborah number, the more fluid it is. We demonstrate the stability of the method in the experimentally relevant range of high Weissenberg numbers. The Weissenberg number indicates the degree of anisotropy or orientation generated by the deformation, and is appropriate to describe flows with a constant stretch history, such as simple shear. The Weissenberg number indicates the degree of anisotropy or orientation generated by the deformation, and is appropriate to describe flows with a constant stretch history, such as simple shear. The difference in material behaviour is characterized by the level and nature of elasticity present in the material when it deforms, which takes the material behaviour to the … On occasions, the characteristic time of observation in the definition of the Deborah number has been taken as L/U, so that D e = λU/L; in these circumstances, the Weissenberg number and Deborah number have essentially the same definition and are used interchangeably, even … A: Being born a man. The first is called the Weissenberg number W e. (Some writers, because of the prior use of W e for the Weber number (ratio of surface tension forces to inertia) prefer to use W i as the symbol.) The Weissenberg number is a dimensionless number used in the study of viscoelastic flows. … It excludes complicated e ects of shear-dependent viscosity and thus allows one to emphasize the in uence of uid s elasticity on characteristics of its boundary layer. Despite their different origins, and the fact that they quantify different effects, they are frequently used as synonyms. The dimensionless number is the ratio of the relaxation time of the fluid and a specific process time. Box 808, L-560, Livermore, CA 94551, USA. Deborah number Last updated December 09, 2020. The Weissenberg number indicates the degree of anisotropy or orientation generated by the deformation, and is appropriate to describe flows with a constant stretch history, such as simple shear. If a rheological experiment is faster than the relaxation process, the material will appear elastic (high De number), otherwise the viscous part will dominate (low De number). Toward a solution to the high Weissenberg number problem David Trebotich∗1 1 Center for Applied Scientific Computing, Lawrence Livermore National Laboratory, P.O. I'm assuming that the Society changed their URLs since I always just cut-and-paste any addresses into my posts. While Wi is similar to the Deborah number and is often confused with it in technical literature, they have different physical interpretations. The Weissenberg number Ws is named after Karl Weissenberg, an early worker in the field of non-Newtonian fluids. 272-304. mehr . The first … Divergent flow in contractions . For instance, in simple steady shear, the Weissenberg number, often abbreviated as Wi or We, is defined as the shear rate times the relaxation time Kontakt. For instance, in simple steady shear, the Weissenberg number, often abbreviated as Wi or We, is defined as the shear rate times the relaxation time (). In contrast, the Deborah number should be used to describe flows with a non-constant stretch history, and physically represents the rate at which elastic energy is stored or released. Deborah numbers of up to .. eupper-convectedMaxwell uidisaclassofviscoelas-tic uid that can explain characteristics of uid relaxation time. Die Relaxationszeit wäre im einfachsten Fall jene aus einem Maxwell-Modell des Fluids. Mesh parameters. Your browser does not support JavaScript. We apologise for any inconvenience. Furthermore, the division between energy and entropy elasticity is investigated in detail with regard to the … I'm that guy. It is named after Karl Weissenberg.The dimensionless number is the ratio of the relaxation time of the fluid and a specific process time. Die Weissenberg-Zahl {\displaystyle {\mathit {Wi}}}, benannt nach dem Physiker und Rheologen Karl Weissenberg, ist eine dimensionslose Kennzahl zur Beschreibung des viskoelastischen Stoffverhaltens von Fluiden. Please note, due to essential maintenance online transactions will not be possible between 09:00 and 13:00 BST, on Monday 20th January 2020 (04:00-08:00 EDT). Dimensionless numbers in fluid mechanics are a set of dimensionless quantities that have an important role in analyzing the behavior of fluids.Common examples include the Reynolds or the Mach numbers, which describe as ratios the relative magnitude of fluid and physical system characteristics, such as density, viscosity, speed of sound, flow speed, etc. Since their introduction to the literature nearly fifty years ago the Deborah and Weissenberg numbers have proved invaluable for rheologists in quantifying viscoelastic effects. The definition of Ws depends on that of t f which is given by: (1) where tr() denotes trace and e denotes strain-rate given in terms of velocity u by: (2) For a simple shear flow with shear-rate γ: (3) while for a simple extensional flow with extension rate ε: (4) Thus for flow … As the Weissenberg number (Wi) increased, the flow developed from a Newtonian-like to vortex growth, ... Dynamics of high-Deborah-number entry flows: a numerical study. 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