Hydraulics/Fluid Mechanics a.y. 2020-2021
AN INTRODUCTION TO TURBULENCE:
Turbulence in pipe flows (pipe flows-part II)
Prof. Stefania Espa
DICEA-SAPIENZA UNIVERSITY OF ROME
CIVIL AND INDUSTRIAL ENGINEERING
BATCHELOR IN SUSTAINABLE BUILDING ENGINEERING
RIETI
All images uploaded are for educational purposes
,1-PIPE FLOWS: Introduction
In this section we’ll introduce the basic concepts related to turbulent regime in
pipe flows presenting the quantity of interest
In most of the cases this is the flow regime that occurs both in pipe and in
open channel flows; on the other hand we know that the equations of motion
in this case become very complicated and it is not possible to recover any
analytical solution for the flow, even in the simplest geometry (circular)
The approach to solve this complicated issue basically consists in:
-considering a statistical definition of all the involved quantities;
-using dimensional analysis;
-consider an empirical validation/measure of quantities
Turbulent flow is assumed to occur in a pipe under standard operating
conditions whenever the Reynolds number exceeds 2000; between 2000 and
4000 it is possible for the flow to randomly oscillate between being laminar
and turbulent. Do you remember how Re is built?
, 1-PIPE FLOWS: Turbulent regime
AN INTRODUCTION TO TURBULENCE:
Turbulence in pipe flows (pipe flows-part II)
Prof. Stefania Espa
DICEA-SAPIENZA UNIVERSITY OF ROME
CIVIL AND INDUSTRIAL ENGINEERING
BATCHELOR IN SUSTAINABLE BUILDING ENGINEERING
RIETI
All images uploaded are for educational purposes
,1-PIPE FLOWS: Introduction
In this section we’ll introduce the basic concepts related to turbulent regime in
pipe flows presenting the quantity of interest
In most of the cases this is the flow regime that occurs both in pipe and in
open channel flows; on the other hand we know that the equations of motion
in this case become very complicated and it is not possible to recover any
analytical solution for the flow, even in the simplest geometry (circular)
The approach to solve this complicated issue basically consists in:
-considering a statistical definition of all the involved quantities;
-using dimensional analysis;
-consider an empirical validation/measure of quantities
Turbulent flow is assumed to occur in a pipe under standard operating
conditions whenever the Reynolds number exceeds 2000; between 2000 and
4000 it is possible for the flow to randomly oscillate between being laminar
and turbulent. Do you remember how Re is built?
, 1-PIPE FLOWS: Turbulent regime
