The purpose of this paper is to dela with the entry flow problem for a micropolar fluid in steady motion in a semi-infinite cylinder pipe.The problem to be studied is "end effect" involving comparison between two motion: the Poiseuille flow (basic flow) and another flow with the same velocity flux. Our main result is an explicit estimate which establishes the rate of exponential decay, with axial distance z from the entry, of the dissipation energy of the perturbation thus providing a qualitative description of the flow development. We find that, under mild hypothesis on the asymptotic behavior of the fields and a smallness assumption on the velucity flux, the flow tends to the Poiseuille flow in the energy norm as z tends to infinity. We give also an upper bound for the perturbation energy through the data of the problem.
Spatial decay estimate in steady motion of a micropolar fluid in a pipe
BORRELLI, Alessandra;PATRIA, Maria Cristina;
2004
Abstract
The purpose of this paper is to dela with the entry flow problem for a micropolar fluid in steady motion in a semi-infinite cylinder pipe.The problem to be studied is "end effect" involving comparison between two motion: the Poiseuille flow (basic flow) and another flow with the same velocity flux. Our main result is an explicit estimate which establishes the rate of exponential decay, with axial distance z from the entry, of the dissipation energy of the perturbation thus providing a qualitative description of the flow development. We find that, under mild hypothesis on the asymptotic behavior of the fields and a smallness assumption on the velucity flux, the flow tends to the Poiseuille flow in the energy norm as z tends to infinity. We give also an upper bound for the perturbation energy through the data of the problem.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
