Many fluids which are of interest in engineering, as bentonite, slurries, fresh concrete, ceramic past, molten polymers, behave as Bingham fluids, i.e. fluids which present a yield stress. This paper investigates numerically the unsteady motion between two coaxial cylinders when the internal one rotates about its axis. The constitutive law of the fluid presents a discontinuity for zero shear rate which introduces severe difficulties in solving any problem of unsteady motion, both analytically and numerically. A suitable way to avoid the obstacle is to regularize the constitutive equation using a smooth function to approximate the Bingham law: in this paper the adopted law is based on the error function. Different procedures of start-up and cessation of flow and some periodical flows are examined numerically using an implicit finite difference method.

I. Daprà, G. Scarpi (2008). UNSTEADY COUETTE FLOW OF A BINGHAM FLUID. PERUGIA : Morlacchi.

UNSTEADY COUETTE FLOW OF A BINGHAM FLUID

DAPRA', IRENE;SCARPI, GIANBATTISTA
2008

Abstract

Many fluids which are of interest in engineering, as bentonite, slurries, fresh concrete, ceramic past, molten polymers, behave as Bingham fluids, i.e. fluids which present a yield stress. This paper investigates numerically the unsteady motion between two coaxial cylinders when the internal one rotates about its axis. The constitutive law of the fluid presents a discontinuity for zero shear rate which introduces severe difficulties in solving any problem of unsteady motion, both analytically and numerically. A suitable way to avoid the obstacle is to regularize the constitutive equation using a smooth function to approximate the Bingham law: in this paper the adopted law is based on the error function. Different procedures of start-up and cessation of flow and some periodical flows are examined numerically using an implicit finite difference method.
2008
XXXI Convegno Nazionale di Idraulica e Costruzioni Idrauliche
1
8
I. Daprà, G. Scarpi (2008). UNSTEADY COUETTE FLOW OF A BINGHAM FLUID. PERUGIA : Morlacchi.
I. Daprà; G. Scarpi
File in questo prodotto:
Eventuali allegati, non sono esposti

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/62646
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact