A qualitative assessment of the role of a viscosity depending on the third invariant of the rate-of-deformation tensor upon turbulent non-Newtonian flow

• Type: Article in International Scientific Journal
• Date: 1998

Authors

Oliveira, PJ (Author) Other; F. T. Pinho (Author) FEUP

Journal

Title: Journal of Non-Newtonian Fluid Mechanics

Vol. 78

Pages: 1-25

ISSN: 0377-0257

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 9 Citations

Scopus - 9 Citations

Other information

Authenticus ID: P-001-7KE

DOI: 10.1016/s0377-0257(97)00107-9

Abstract (EN): The numerical simulation of some non-Newtonian effects in wall and wall-free turbulent flows, such as drag reduction in pipe flows or the decrease in transverse normal Reynolds stresses, has been attempted in the past with a limited degree of success on the basis of modified wall functions applied to traditional turbulence models (k-epsilon), rather than through more realistic rheological constitutive equations. In this work, it is qualitatively shown that if the viscosity function of a generalised Newtonian fluid is assumed to depend on the third invariant of the rate of deformation tensor, there is an increase of the viscous diffusion terms, but especially, of the dissipation of turbulence kinetic energy by a factor equal to the Trouton ratio of the fluid, divided by the Trouton ratio of the solvent, thus indicating a possible way to improve rheological-turbulence modelling.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 25