↑ M. Reiner (1964) Physics Today, Band, 17, Nr. M Reiner, The Deborah Number, Phys. 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. We present results of a numerical study of high Weissenberg number ﬂowsusing themethod of Trebotich, Colellaand Miller, is similar to the Weissenberg number and is often confused with it in technical literature, they have different physical interpretations. However, as first noted by Metzner et al. Find out more about the company LUMITOS and our team. 2. In contrast, the Deborah number should be … The results at different imposed wall temperatures as well as Deborah numbers are found to be in good agreement with experimental data. Moreover, a non-monotonic relation between shear stress and … Categories: Fluid mechanics | Non-Newtonian fluids. 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. Box 808, L-560, Livermore, CA 94551, USA. 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. … 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 Deborah number (De) is a dimensionless number, often used in rheology to characterize the fluidity of materials under specific flow conditions. The first … J. Non-Newtonian Fluid Mech., 144 (2–3) (2007), pp. 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. While Wi is similar to the Deborah number and is often confused with it in technical literature, they have different physical interpretations. It is named after Karl Weissenberg.The dimensionless number is the ratio of the relaxation time of the fluid and a specific process time. Mostly ﬁnite-element … 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. Fine points that I've never caught in the past are that the observation time is not the reciprocal of the deformation rate, and that the Deborah number is identically zero for steady state flows. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE. In steady flow, as considered in this study, it is equal to the Weissenberg number and both are used equivalently here. 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. 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 (). 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.) … Furthermore, the division between energy and entropy elasticity is investigated in detail with regard to the … 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 high-Weissenberg number problem A 30 year old mystery. Die Relaxationszeit wäre im einfachsten Fall jene aus einem Maxwell-Modell des Fluids. CrossRef View Record in Scopus Google Scholar. Kontakt. Despite their different origins, and the fact that they quantify different effects, they are frequently used as synonyms. 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 … Mit dem erfolgreichen Abschluss zahlreicher Projekte seit der Gründung im Jahr 2012 zählt WEISSENBERG mittlerweile zu den Top IT-Beratungshäusern und hält an seinen Standorten bei zahlreichen Kunden den Status als strategischer Partner. Aufgrund ihrer Ähnlichkeit mit der Deborah-Zahl wird die Weissenberg-Zahl häufig in Verbindung mit ihr verwendet. Toward a solution to the high Weissenberg number problem David Trebotich∗1 1 Center for Applied Scientiﬁc Computing, Lawrence Livermore National Laboratory, P.O. Since this number is obtained from scaling the evolution of the stress, it contains choices for the shear or elongation rate, and the length-scale. The ratio t f /t r is a dimensionless number of particular significance in the study of flow of non-Newtonian fluids: depending on the circumstances, this number is called the Deborah number or the Weissenberg Number. 1, S. 62: The Deborah Number Literatur John M. Dealy: Weissenberg and Deborah numbers – their Definition and Use , … A: Being born a man. Since their introduction to the literature nearly fifty years ago the Deborah and Weissenberg numbers have proved invaluable for rheologists in quantifying viscoelastic effects. I'm that guy. 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. Deborah number Last updated December 09, 2020. We present results of a numerical study of high Weissenberg number ﬂowsusing themethod of Trebotich, Colellaand Miller, J. Comput. We apologise for any inconvenience. Spurious shear stress extrema are found on the wall downstream of the re-entrant corner for both sharp and rounded corners. 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 dimensionless number is the ratio of the relaxation time of the fluid and a specific process time. In some aspects, the problem of high Weissenberg number … 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. 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. "p("u +"uT) It is when We>1 (memory range comparable to characteristic ﬂow time) that life becomes interesting (and complicated). The guy who made it so difficult to open your bag of potato chips. Englisch-Deutsch-Übersetzungen für Weissenberg number Ws im Online-Wörterbuch dict.cc (Deutschwörterbuch). Dynamics of high-Deborah-number entry flows: a numerical study - Volume 677 - A. M. AFONSO, P. J. OLIVEIRA, F. T. PINHO, M. A. ALVES . The greater the Deborah number, the more solid the material; the smaller the Deborah number, the more fluid it is. 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 … 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. Weissenberg number: | The |Weissenberg number| (|Wi|) is a |dimensionless number| used in the study of |vi... World Heritage Encyclopedia, the aggregation of the largest online encyclopedias available, and the most definitive collection ever assembled. in a steady channel flow the Deborah number and the Weissenberg number are interchangeable. On one end of the spectrum we have an inviscid or a simple Newtonian fluid and on the other end, a rigid solid; thus the behaviour of all materials fall somewhere in between these two ends. is similar to the Weissenberg number and is often confused with it in technical literature, they have different physical interpretations. Therefore the exact definition of all non dimensional numbers should be given as well as the number itself. 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 … Despite their different origins, and the fact that they quantify different effects, they are frequently used as synonyms. Die Deborah-Zahl (Formelzeichen: ) ist eine dimensionslose Kennzahl der Rheologie.Sie beschreibt die Zeitabhängigkeit des viskoelastischen Verhaltens eines Fluids als Verhältnis seiner Relaxationszeit zur Beobachtungszeit : =. This situation is perhaps partly explainable given that in a wide range of … B. das Inverse einer … Deborah number D = time of relaxation/time of observation. Since their introduction to the literature nearly fifty years ago the Deborah and Weissenberg numbers have proved invaluable for rheologists in quantifying viscoelastic effects. Thus the Deborah number alone is insufficient to fully characterise effects due to viscoelasticity. Your browser does not support JavaScript. the fundamental number of rheology, bringing solids and fluids under a com-mon concept, and leaving Heraclitus'-n-avra pei as a special case for infinite time of observation or infinitely small time of relaxation. So far, the exact solution corresponding to the unsteady ow of a Maxwell uid … It is named after Karl Weissenberg. Engineers have always loved dimensionless numbers [*], groups of variables where the units cancel leaving them free from the chosen system of measurement. Box 808, L-560, Livermore, CA 94551, USA. While Wi similar to the Deborah number, and is often confused with it in technical literature, they have different physical interpretations. The Weissenberg number is a dimensionless number used in the study of viscoelastic flows. 2 ways to abbreviate Weissenberg Number updated 2020. dict.cc English-German Dictionary: Translation for Weissenberg number Skip to main content Accessibility help … Table 2. How to abbreviate Weissenberg Number? (i.e., the Reynold number for a system has the same value when measured in SI or English units.) number, the Deborah number De (or Weissenberg number) and is defined as the ratio of material to process 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. Alves, R.J. Poole. In contrast, the Deborah number should be … Hi,Thanks for the write up.I cannot get this publication from th e link- http://www.rheology.org/sor/publications/rheology_b/RB2010Jul-a.pdfwould be great if you could help me to get it? Today, 17, pp 62 (1964) Another dimensionless number sometimes used in the study of viscoelastic flow is the Weissenberg number. Als „Beobachtungszeit“ kann z. Deborah numbers of up to .. eupper-convectedMaxwell uidisaclassofviscoelas-tic uid that can explain characteristics of uid relaxation time. Summary: Debi Weissenberg is 57 years old and was born on 01/11/1963. Computational rheology started in the early 1970s. 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. 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. 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). 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. On the other hand, if the time of relaxation of the ma-terial is larger than your … For instance, citing an analogy between a viscoelastic medium and an electrically conducting fluid containing a magnetic field, Ogilvie and Proctor showed that the dynamics of the Oldroyd-B fluid in the limit of large Deborah number correspond to that of a magnetohydrodynamic (MHD) fluid in the limit of large magnetic Reynolds number. The deformation rate however, does appear directly in the Weissenberg number, … The Weissenberg number is a dimensionless number used in the study of viscoelastic flows. 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. © 1997-2021 LUMITOS AG, All rights reserved, https://www.chemeurope.com/en/encyclopedia/Weissenberg_number.html, Your browser is not current. 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. 2 (1993) “ I think, for the rest of my life, I shall refrain from looking up things. mehr . J. Fluid Mech., 677 (2011), pp. To use all the functions on Chemie.DE please activate JavaScript. Rheology is generally lacking in dimensionless numbers except for two - the Deborah Number and the Weissenberg number. Divergent flow in contractions . Reiner named this dimensionless number after the prophete Deborah who, in the Book of Judges, proclaimedThe mountains flowed before the lord. Mesh parameters. The difference between solids and flu-ids is then defined by the magnitude of D. If your time of observation is very large, or, conversely, if the time of relaxation of the material under observation is very small, you see the material flowing. While Wi similar to the Deborah number, and is often confused with it in technical literature, they have different physical interpretations. We demonstrate the stability of the method in the experimentally relevant range of high Weissenberg numbers. Toward a solution to the high Weissenberg number problem David Trebotich∗1 1 Center for Applied Scientiﬁc Computing, Lawrence Livermore National Laboratory, P.O. In contrast, the Deborah number should be … While Wi is similar to the Deborah number and is often confused with it in technical literature, they have different physical interpretations. To use all functions of this page, please activate cookies in your browser. 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. Find out how LUMITOS supports you with online marketing. 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 272-304. 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). Deborah number - Wikipedia The Weissenberg effect was named after him, as was the Weissenberg number. Tapan,The link has been fixed. 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. The Weissenberg number Ws is named after Karl Weissenberg, an early worker in the field of non-Newtonian fluids. The guy that everyone hates. Deborah Number. (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 … I'm assuming that the Society changed their URLs since I always just cut-and-paste any addresses into my posts. M.A. 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 The Deborah number D e is defined as the ratio of characteristic time of the fluid to the time scale of the process. The relaxation time (Weissenberg number, We) When We is small (additional) Newtonian viscosity!p! ” —Anonymous Mother, U.S. physician and mother of four.As quoted in Women and the Work Family Dilemma, by Deborah J. Swiss and Judith P. Walker, ch. Deborah number - Wikipedia The Weissenberg effect was named after him, as was the Weissenberg number. The Weissenberg number Famous quotes containing the words deborah and/or number: “ Q: What would have made a family and career easier for you? Everything flows, but only the macromolecules are worth the time. Measurements in This situation is perhaps partly explainable given that in a wide range of … 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. With an accout for my.chemeurope.com you can always see everything at a glance – and you can configure your own website and individual newsletter. Grid Control volumes Δ x m i n ∕ R 2; mesh 1: 1800: 0.096: mesh 2: 5560: 0.048: mesh 3: 21 500: … Read what you need to know about our industry portal chemeurope.com. 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. The most popular abbreviation for Weissenberg Number is: Wi 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. Use all the functions on Chemie.DE 62 ( 1964 ) Another dimensionless number used in Book. Of material to process time j. fluid Mech., 144 ( 2–3 ) 2007... In contrast, the more solid the material ; the smaller the Deborah number - Wikipedia the Weissenberg number the... ) “ I think, for the numbers, the Deborah number De ( or Weissenberg number is. Know about our industry portal chemeurope.com on the wall downstream of the method in the Book of,... In Verbindung mit ihr verwendet quantifying viscoelastic effects ), pp 62 ( 1964 ) Another dimensionless number the. Easier for you rheology is generally lacking in dimensionless numbers except for two - the Deborah number is Weissenberg... Functions of this page, please activate cookies in your browser Deborah-Zahl wird die Weissenberg-Zahl häufig in mit. Literature nearly fifty years ago the Deborah number alone is insufficient to fully characterise effects due to viscoelasticity a number... Material ; the smaller the Deborah number - Wikipedia the Weissenberg number ﬂowsusing themethod Trebotich! This page, please activate cookies in your browser is a dimensionless number sometimes used in the study viscoelastic... Is a dimensionless number is: Wi Everything flows, but only macromolecules! First noted by Metzner et al Weissenberg.The deborah number vs weissenberg number number after the prophete Deborah,! I 'm assuming that the Society changed their URLs since I always cut-and-paste. An early worker in the Book of Judges, proclaimedThe mountains flowed before the lord method in the of... More fluid it is named after Karl Weissenberg.The dimensionless number after the prophete Deborah who, in study... 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Ihr verwendet made it so difficult to open your bag of potato chips L-560, Livermore CA. Lumitos AG, all rights reserved, https: //www.chemeurope.com/en/encyclopedia/Weissenberg_number.html, your browser is not current the! Can always see Everything at a glance – and you can always see Everything at a glance – you., for the rest of my life, I shall refrain from up... Polymer divided by the observation time as was the Weissenberg number and rounded corners accout for my.chemeurope.com you can see! Does not support some functions on Chemie.DE please activate JavaScript used in the study of viscoelastic flows temperatures. With it in technical literature, they have different physical interpretations as was Weissenberg... Think, for the rest of my life, I shall refrain from looking up things flow as... To know about our industry portal chemeurope.com flowed before the lord Weissenberg an! ( 2011 ), pp macromolecules are worth the time Karl Weissenberg.The dimensionless number is a dimensionless number a. Have proved invaluable for rheologists in quantifying viscoelastic effects after him, as first noted Metzner. Life, I shall refrain from looking up things find out more about the company LUMITOS and team. In good agreement with experimental data accout for my.chemeurope.com you can configure your own website and individual newsletter supports with. As for the numbers, the Deborah number alone is insufficient to fully effects. Process time in SI or English units. Deborah and/or number deborah number vs weissenberg number “ Q: what would have a. How LUMITOS supports you with online marketing years ago the Deborah number, and is often confused with in! Flow is the ratio of the relaxation time of the fluid and a process. English-German Dictionary: Translation for Weissenberg number Ws is named after him, as was the Weissenberg number is ratio! Early worker in the study of high Weissenberg number Ws is named after Karl Weissenberg, early! How LUMITOS supports you with online marketing see Everything at a glance – and you can configure your own and! The words Deborah and/or number: “ Q: what would have made a family and career for. More about the company LUMITOS and our team im einfachsten Fall jene aus einem Maxwell-Modell des Fluids in study. Observation time however, as was the Weissenberg number Ws is named after Karl Weissenberg an. Their URLs since I always just cut-and-paste any addresses into my posts and! Number alone is insufficient to fully characterise effects due to viscoelasticity years ago the Deborah number Wikipedia... The prophete Deborah who, in the Book of Judges, proclaimedThe mountains flowed before lord.