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. How to say Weissenberg in English? Therefore the exact definition of all non dimensional numbers should be given as well as the number itself. Jewish (Ashkenazic): variant of Weissberg. 2 number, Re=ρV η 0 and the Weissenberg number Wi =λV respectively. The Weissenberg number (Wi) is a dimensionless number used in the study of viscoelastic flows.It is named after Karl Weissenberg. The most Weissenberg families were found in the USA in 1920. Wikipedia, Author provided. 1.4.1 Weissenberg Rod Climbing Effect When a liquid is stirred using a cylindrical rod, the liquid that wets the rod begins to “climb” up the rod and the interface with the surrounding a ir assumes a steady shape dangling to the rod, so long as there is a continuous rotation. This is because as the shear rate is increased, the uid behind the wake is stretched more and more, therefore requiring a larger distance to relax. The quantity (N 1 /σ) is often called the stress ratio. Definition… …   Wikipedia, Deborah number — The Deborah number is a dimensionless number, often used in rheology to characterize the fluidity of materials under specific flow conditions. 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. In 1880 there were 2 Weissenberg families living in Wisconsin. The dimensionless number is the ratio of the relaxation time of the fluid and a specific process time. The ratio t r /t f 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 Weissenberg Number or the Deborah Number. The Weissenberg number (Wi) is a dimensionless number used in the study of viscoelastic flows. Looking for abbreviations of HWNP? 185.232.66.180, © Springer Science+Business Media, LLC 2011, https://doi.org/10.1007/978-1-4419-6247-8, Reference Module Physical and Materials Science. This service is more advanced with JavaScript available. Weissenberg number The Weissenberg number is a dimensionless number used in the study of viscoelastic flows. In gure 3, the force required to move the sphere at a constant velocity through the uid is plotted against Weissenberg number (which for this case may be thought of as Comparing this duration and the relaxation time produces the Reynolds number in the case of fluids dominated by inertia (like water), or the Weissenberg number for those dominated by elasticity (like cake batter). The dimensionless number compares the viscous forces to the elastic forces. Wisconsin had the highest population of Weissenberg families in 1880. The dimensionless number compares the elastic forces to the viscous forces. It is named after Karl Weissenberg. He invented a Goniometer to study X ray diffraction of crystals …   Wikipedia, Nusselt number — In heat transfer at a boundary (surface) within a fluid, the Nusselt number is the ratio of convective to conductive heat transfer across (normal to) the boundary. It is named after Karl Weissenberg. The materials of the same grade but different batches can be processed in a different manner. It can be variously defined, but it is usually given by the relation of stress relaxation time of the fluid and a specific process time. The Weissenberg number (Wi) is a dimensionless number used in the study of viscoelastic flows. It is defined as: Where μ is the liquid viscosity ρ is the liquid density σ is the surface tension L is the characteristic …   Wikipedia, Dean number — The Dean number is a dimensionless group in fluid mechanics, which occurs in the study of flow in curved pipes and channels. Deborah number, De, increases. I must confess that I never really understood there to be much difference between the two, but a new article in the Rheology Bulletin (pdf file, open access, article starts on p. 14) makes clear the difference. It is High Weissenberg Number Problem. Not affiliated “ ustratingly low value” of the Weissenberg number (usually around We=1; precise critical value varies with the flow geometry). (Some writers, because of the prior use of We for the Weber number (ratio of surface tension forces to inertia) prefer to use Wi as the symbol.) Rheology is generally lacking in dimensionless numbers except for two - the Deborah Number and the Weissenberg number. The dimensionless number is the ratio of the relaxation time of the fluid and a specific process time. OK. b The Weissenberg number has sometimes been considered to be (N 1 /σ). Another dimensionless number sometimes used in the study of viscoelastic flow is the Weissenbergnumber. The dimensionless number compares the elastic forces to the viscous forces. However, this is a ratio of dependent rather than independent variables and thus describes data rather than experimental conditions. Definition of the velocity gradient. The Weissenberg number is a dimensionless number used in the study of viscoelastic flows. Source: Dictionary of American Family Names ©2013, Oxford University Press. In fluid dynamics, the Keulegan–Carpenter number, also called the period number, is a dimensionless quantity describing the relative… …   Wikipedia, Ohnesorge number — The Ohnesorge number, Oh, is a dimensionless number that relates the viscous forces to inertial and surface tension forces. Evidence that it is a numerical phenomenon (but inconclusive whether higher resolution delays of promotes breakdown). 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 Over 10 million scientific documents at your fingertips. The Weissenberg number is a dimensionless number used in the study of viscoelastic flows. It can be variously defined, but it is usually given by the relation of stress relaxation time of the fluid and a specific process time. Pronunciation of Weissenberg with 1 audio pronunciation, 2 translations and more for Weissenberg. (New) In the flow of viscoelastic liquids, the dimensionless Weissenberg number represents the ratio of the viscoelastic force to the viscous force and has sometimes been equated to N1/2τ, where N1 = the first normal stress in a viscoelastic fluid flowing in simple shear and τ = the shear stress. While Wi similar to the Deborah number, and is often confused with it in technical literature, they have different physical interpretations. HWNP - High Weissenberg Number Problem. The Weissenberg number indicates the degree of anisotropy or orientation generated by the deformation, and is appropriate to describe flows with a … Weissenberg number, Wi A measure of the degree of nonlinearity or the degree to which normal stress differences are exhibited in a flow. © 2020 Springer Nature Switzerland AG. 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 general Weissenberg number can also be used to characterize the elastic effects of non-Newtonian fluids in laminar flow. 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. It is named after Karl Weissenberg. The transformation process reacts to small changes in the material i.e. It is named after Karl Weissenberg. Weissenberg — may refer to: *Weißenberg, a town in Saxony, Germany *the scene of the Battle of White Mountain *Karl Weissenberg (1893 1976), German physicist and founding rheologist, after whom the Weissenberg effect was named *Alexis Weissenberg (b. The dimensionless number compares the viscous forces to the elastic forces. Here V and are characteristic velocity and length scales for the flow of interest and ρ,η 0,λ are the density, viscosity and longest – or characteristic – relaxation time of the test fluid. The Weissenberg effect was named after him, as was the Weissenberg number. The Weissenberg number was originally defined as the ratio of normal stress difference to shear stress 36, 56. 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