Streak images, laser Doppler velocimetry (LDV) [ Topic. A large enhanced pressure drop above that of a Newtonian fluid is observed independent of contraction ratio and re-entrant corner curvature. This instability is a precursor to an unsteady vortex that develops upstream of the cylin-der at higher Deborah numbers. Shortly after Reiner’s work, the significance of the Deborah number was discussed within a more Deborah number. The mathematical treatment of the problem shows that, for a given Deborah number, there is a critical draw ratio above which there is no mathematical solution. The size and steadiness of the upstream vortex are primarily controlled by the Deborah and the elasticity number. Deborah number. From an experimental point of view, the data show a good qualitative agreement with the model. Small Deborah numbers represent Newtonian flow, while non-Newtonian (with both viscous and elastic effects present) behaviour occurs for intermediate range Deborah numbers, and high Deborah numbers indicate an elastic/rigid solid. This wide range of reported Deborah numbers at the onset of extensional viscosity is due to difficulties in calculating stretch rates in porous media. 2.9. One of Maxwell’s ideas: viscous flow is the decay of elastically stored energy; molecules in a low energy state are displaced to a higher energy state and time is required for the energy to “relax”; a time called the relaxation time, $\backslash tau$. range of Deborah numbers. The ratio of both, the De (Deborah) number is an important process parameter. It characterises the fluid's flow regime: a value in a certain lower range denotes laminar flow; a value in a higher range, turbulent flow. (b) Calculate the Deborah number of the LDPE sample and compare the Deborah number of glass at 27°C having a relaxation time of 105 s for the same observation time with the LDPE. Deborah number above 10. The ideal elastic fluid is dilute, monodisperse and well characterized in both shear and transient uniaxial extension. is a function of the Deborah number (De). Active Pass: Added mass: Since Deborah number is a relative quantity, the numerator or the denominator can alter the number. Both instabilities occur at moderate Reynolds numbers but are fundamentally elastic. 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. The residence time is the period that the polymers experience a specific strain rate, listed in Table 1. Deborah number is similar to these topics: Graetz number, Weissenberg number, Euler number (physics) and more. Academic disciplines Business Concepts Crime Culture Economy Education Energy Events Food and drink Geography Government Health Human behavior Humanities Knowledge Law Life Mind Objects Organizations People Philosophy Society Sports Universe World Arts Lists Glossaries. The Deborah number (which is now commonly abbreviated to De rather than D) thus distinguishes how a particular material will behave over a given timeframe (we inherently assume that the material must be experiencing a deformation over this timeframe). De is defined as the ratio of polymer (or multimer) relaxation time to flow residence time, and therefore defines how stretched VWF is likely to be. The smaller the Deborah number, the higher is the maximum attainable draw ratio. 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