A Burgers-Type Model of Turbulent Decay in a Non-Newtonian FluidSource: Journal of Applied Mechanics:;1972:;volume( 039 ):;issue: 003::page 661DOI: 10.1115/1.3422769Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: To study the effects of the high elongational viscosity on the free (“grid-generated”) turbulence of polymer solutions, a Burgers-type model equation is proposed and formed by replacing the Newtonian viscosity of the original Burgers equation with a non-Newtonian viscosity. By using the proposed model equation, numerical experiments were carried out to compute the energy decays, the changes in the energy spectra, and the variations of the mean square of the velocity gradient with time. Comparisons between the Newtonian and the non-Newtonian cases were based on the same Reynolds numbers and the same initial random velocity fields generated by a Gaussian process with two types of spectrum. Measurements on real grid turbulence are discussed in the light of these calculations. The computational results show, in general, the suppression of “shock waves” because of the non-Newtonian viscosity effect, but the turbulent decay rate at large Reynolds number is not always increased, which is surprising. It appears that the calculations support qualitatively the idea of vortex stretching inhibition in polymer turbulence due to high elongational viscosity.
keyword(s): Turbulence , Non-Newtonian fluids , Viscosity , Equations , Spectra (Spectroscopy) , Reynolds number , Measurement , Shock waves , Gradients , Polymer solutions , Polymers AND Vortices ,
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contributor author | Y. Kuo | |
contributor author | R. I. Tanner | |
date accessioned | 2017-05-09T01:15:32Z | |
date available | 2017-05-09T01:15:32Z | |
date copyright | September, 1972 | |
date issued | 1972 | |
identifier issn | 0021-8936 | |
identifier other | JAMCAV-25966#661_1.pdf | |
identifier uri | http://yetl.yabesh.ir/yetl/handle/yetl/157234 | |
description abstract | To study the effects of the high elongational viscosity on the free (“grid-generated”) turbulence of polymer solutions, a Burgers-type model equation is proposed and formed by replacing the Newtonian viscosity of the original Burgers equation with a non-Newtonian viscosity. By using the proposed model equation, numerical experiments were carried out to compute the energy decays, the changes in the energy spectra, and the variations of the mean square of the velocity gradient with time. Comparisons between the Newtonian and the non-Newtonian cases were based on the same Reynolds numbers and the same initial random velocity fields generated by a Gaussian process with two types of spectrum. Measurements on real grid turbulence are discussed in the light of these calculations. The computational results show, in general, the suppression of “shock waves” because of the non-Newtonian viscosity effect, but the turbulent decay rate at large Reynolds number is not always increased, which is surprising. It appears that the calculations support qualitatively the idea of vortex stretching inhibition in polymer turbulence due to high elongational viscosity. | |
publisher | The American Society of Mechanical Engineers (ASME) | |
title | A Burgers-Type Model of Turbulent Decay in a Non-Newtonian Fluid | |
type | Journal Paper | |
journal volume | 39 | |
journal issue | 3 | |
journal title | Journal of Applied Mechanics | |
identifier doi | 10.1115/1.3422769 | |
journal fristpage | 661 | |
journal lastpage | 666 | |
identifier eissn | 1528-9036 | |
keywords | Turbulence | |
keywords | Non-Newtonian fluids | |
keywords | Viscosity | |
keywords | Equations | |
keywords | Spectra (Spectroscopy) | |
keywords | Reynolds number | |
keywords | Measurement | |
keywords | Shock waves | |
keywords | Gradients | |
keywords | Polymer solutions | |
keywords | Polymers AND Vortices | |
tree | Journal of Applied Mechanics:;1972:;volume( 039 ):;issue: 003 | |
contenttype | Fulltext |