I-2 Ideal Fluid Flows and Irrotational Flow Motion

2009 ◽  
pp. 43-68
Keyword(s):  
Ideal Fluid ◽  
Fluid Flows ◽  
Irrotational Flow ◽  
Flow Motion

Effects of Inclination Angle of Ribs on the Flow Behavior in Rectangular Ducts

2004 ◽  
Vol 126 (4) ◽  
pp. 692-699 ◽  
Author(s):  
Xiufang Gao ◽  
Bengt Sunde´n
Keyword(s):  
Velocity Component ◽  
Flow Direction ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Fluid Flows ◽  
Streamwise Velocity ◽  
Flow Structures ◽  
Local Flow ◽  
Flow Motion ◽  
Streamwise Velocity Component

The flow behavior in rib-roughened ducts is influenced by the inclination of ribs and the effect is investigated in the present study by Particle Image Velocimetry (PIV). The local flow structures between two adjacent ribs were measured. The Reynolds number was fixed at 5800. The flow field description was based on the PIV results in planes both parallel and perpendicular to the ribbed walls at various locations. The rib angle to the main flow direction was varied as 30 deg, 45 deg, 60 deg and 90 deg. The ribs induce three dimensional flow fields. The flow separation and reattachment between adjacent ribs are clearly observed. In addition, the inclined ribs are found to alter the spanwise distribution of the streamwise velocity component. The streamwise velocity component has its highest values at the upstream end of the ribs, and decreases continuously to its lowest values at the downstream end. Strong secondary flow motion occurs over the entire duct cross section for the inclined ribs. The flow structures between two consecutive ribs show that the fluid flows along the ribs from one end of the ribs to the other end, and then turns back at the transverse center. Downwash and upwash flows are observed at the upstream end and downstream end of the ribs, respectively.

Maximisation and minimisation on classes of rearrangements

1991 ◽  
Vol 119 (3-4) ◽  
pp. 287-300 ◽  
Author(s):  
G. R. Burton ◽  
J. B. McLeod
Keyword(s):  
Angular Momentum ◽  
Finite Number ◽  
Bounded Domain ◽  
Ideal Fluid ◽  
Fluid Flows ◽  
Linear Constraints ◽  
Dirichlet Integral ◽  
The One

SynopsisMaximisation and minimisation of the Dirichlet integral of a function vanishing on the boundary of a bounded domain are studied, subject to the constraint that the Laplacean be a rearrangement of a given function. When the Laplacean is two-signed, non-existence of minimisers is proved, and some information on the limits of minimising sequences obtained; this contrasts with the known existence of minimisers in the one-signed case. When the domain is a ball and the Laplacean is one-signed, maximisers and minimisers are shown to be radial and monotone. Existence of maximisers is proved subject additionally to a finite number of linear constraints, with particular reference to ideal fluid flows of prescribed angular momentum in a disc.

Harmonic Maps and Ideal Fluid Flows

2011 ◽  
Vol 204 (2) ◽  
pp. 479-513 ◽  
Author(s):  
A. Aleman ◽  
A. Constantin
Keyword(s):  
Ideal Fluid ◽  
Harmonic Maps ◽  
Fluid Flows

scholarly journals Supercritical flow of an ideal fluid over a spillway

1977 ◽  
Vol 20 (2) ◽  
pp. 211-225
Author(s):  
I. L. Collings ◽  
R. Grimshaw
Keyword(s):  
Froude Number ◽  
Ideal Fluid ◽  
Asymptotic Expansions ◽  
Matched Asymptotic Expansions ◽  
Inviscid Fluid ◽  
Supercritical Flow ◽  
Irrotational Flow ◽  
Outer Expansion

AbstractThe irrotational flow of an incompressible, inviscid fluid over a spiliway is considered. The reciprocal ε of the Froude number is taken to be small and the method of matched asymptotic expansions is applied. The bed of the spillway is horizontal far upstream and makes an angle α with the horizontal far downstream. The inner expansion is valid upstream and over the spillway, but is invalid far downstream. The outer expansion which is valid downstream fails to satisfy the upstream conditions. Unknown constants in the outer expansion are determined by the matching and composite expansions obtained.

Sign in / Sign up

Export Citation Format

Share Document