Aeroelastic Stability of Wide Webs and Narrow Ribbons

2007 ◽  
Author(s):  
Rahul A. Bidkar ◽  
Arvind Raman ◽  
Anil K. Bajaj
Keyword(s):  
Fluid Flow ◽  
Critical Role ◽  
Cross Flow ◽  
Aeroelastic Stability ◽  
Lattice Method ◽  
Flutter Instability ◽  
Divergence Instability ◽  
Applied Tension ◽  
Unsteady Fluid ◽  
The Web

Uni-axially tensioned wide webs and narrow ribbons commonly used in the paper-handling, textile, sheet-metal, and plastics industries are known to undergo large amplitude vibrations characterized as aeroelastic flutter. The aeroelastic stability of stationary wide webs and narrow ribbons coupled with fluid flow across the free edges of the web or ribbon is investigated in this article. The web or ribbon is modeled as a uni-axially tensioned Kirchhoff plate with vanishingly small bending stiffness. The 3D unsteady fluid flow surrounding the web or ribbon is evaluated numerically by using the vortex-lattice method. Wide webs are mainly found to exhibit the divergence instability. For some values of the applied tension, the clustered web modes exhibit frequency curve veering accompanied by a weak flutter instability before the occurrence of the divergence instability. The applied tension plays a critical role in deciding the type of instability in narrow ribbons. In cross flow, depending on the applied tension, narrow ribbons undergo flutter instability or divergence instability or the simultaneous onset of both instabilities.

Aeroelastic Stability of Wide Webs and Narrow Ribbons in Cross Flow

2008 ◽  
Vol 75 (4) ◽  
Author(s):  
Rahul A. Bidkar ◽  
Arvind Raman ◽  
Anil K. Bajaj
Keyword(s):  
Three Dimensional ◽  
Cross Flow ◽  
Coupled System ◽  
Inviscid Fluid ◽  
Aeroelastic Stability ◽  
Aeroelastic Flutter ◽  
Panel Methods ◽  
Divergence Instability ◽  
Applied Tension ◽  
The Web

Aeroelastic flutter can lead to large amplitude oscillations of tensioned wide webs and narrow ribbons commonly used in the paper-handling, textile, sheet-metal, and plastics industries. In this article, we examine the aeroelastic stability of a web or a ribbon, which is submerged in an incompressible and inviscid fluid flow across its free edges. The web or ribbon is modeled as a uniaxially tensioned Kirchhoff plate with vanishingly small bending stiffness. A Galerkin discretization for the structural dynamics together with panel methods for the unsteady three dimensional potential flow are used to cast the coupled system into the form of a gyroscopic, nonconservative dynamical system. It is found that wide webs mainly destabilize through a divergence instability due to the cross-flow-induced conservative centrifugal effects. However, for certain values of applied tension, the wake-induced nonconservative effects can destabilize the web via a weak flutter instability. Contrarily, narrow ribbons in cross flow are nearly equally likely to undergo flutter or divergence instability depending on the value of applied tension.

Bending-Torsional Flutter of a Slender Web in a Cross Flow

2017 ◽  
Author(s):  
Keiichi Hiroaki ◽  
Nobuhito Kawai ◽  
Masahiro Watanabe
Keyword(s):  
Cross Flow ◽  
The Finite Element Method ◽  
Wind Tunnel Experiments ◽  
Fluid Force ◽  
Coupled Mode ◽  
Flutter Analysis ◽  
Unsteady Fluid ◽  
Work Done ◽  
The Web ◽  
Local Work

This paper presents a flutter analysis of a slender web in a cross air flow. In the flutter analysis, a Doublet-point method (DPM) [1] based on an unsteady lifting surface theory is used to calculate the unsteady fluid force acting on the sheet surface. The equation of motion of the web with tension is derived by using the finite element method (FEM). Flutter velocity, frequency and mode are examined through the root locus of the flutter determinant of the system with changing flow velocity of air. In this study, these flutter characteristics derived by flutter analysis are compared with wind-tunnel experiments. The influence of tension of the web on flutter velocity, frequency and mode is clarified. As tension of the web becomes higher, the flutter velocity and corresponding frequency increase. In any tension, coupled mode flutter of bending and torsional modes occurs. Then, local work done by the fluid force around the upstream end of the web is positive. On the other hand, near the downstream end of the web, the local work is negative.

scholarly journals Fluid boundaries shaping using the method of kinetic balance

2006 ◽  
Vol 10 (4) ◽  
pp. 153-162
Author(s):  
Miroslav Benisek ◽  
Svetislav Cantrak ◽  
Milos Nedeljkovic ◽  
Djordje Cantrak ◽  
Dejan Ilic ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Fluid Mechanics ◽  
Cross Sections ◽  
Hydraulic Engineering ◽  
Optimum Shape ◽  
Curved Channels ◽  
Unsteady Fluid Flow ◽  
Unsteady Fluid ◽  
Flow Boundaries ◽  
Dead Water

Fluid flow in curved channels with various cross-sections, as a common problem in theoretical and applied fluid mechanics, is a very complex and quite undiscovered phenomenon. Defining the optimum shape of the fluid flow boundaries, which would ensure minimum undesirable phenomena, like "dead water" zones, unsteady fluid flow, etc., is one of the crucial hydraulic engineering?s task. Method of kinetic balance is described and used for this purpose, what is illustrated with few examples. .

scholarly journals INTEGRATED MODEL «RESERVOIR - WELL - PUMP» FOR UNSTEADY FLUID FLOW REGIMES CALCULATING

2021 ◽  
Vol 19 (1) ◽  
pp. 33
Author(s):  
A.A. Pashali ◽  
R.S. Khalfin ◽  
D.V. Silnov ◽  
A.S. Topolnikov ◽  
B.M. Latypov ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Flow Regimes ◽  
Integrated Model ◽  
Unsteady Fluid Flow ◽  
Unsteady Fluid ◽  
Fluid Flow Regimes

THE IMPACT OF SELECTED PARAMETERS ON PRESSURE DISTRIBUTION IN THE FACE THROTTLE OF A CENTRIFUGAL PUMP AUTOMATIC BALANCING DEVICE

Tribologia ◽  
2021 ◽  
Vol 297 (3) ◽  
pp. 35-44
Author(s):  
Yuliia Tarasevych ◽  
Nataliia SOVENKO
Keyword(s):  
Fluid Flow ◽  
Pressure Distribution ◽  
Hydrodynamic Pressure ◽  
Centrifugal Pumps ◽  
Unsteady Fluid Flow ◽  
The Face ◽  
Unsteady Fluid ◽  
Angular Displacements ◽  
Automatic Balancing ◽  
The Impact

Face throttles are a necessary functional element of non-contact face seals and automatic balancing devices of centrifugal pumps of different constructions. To calculate the hydrodynamic forces and moments acting on the rotor and fluid flow through the automatic balancing device, it is necessary to know the pressure distribution in the cylindrical and face throttle when considering all important factors which predetermine fluid flow. The face throttle surfaces are moving, which leads to unsteady fluid flow. The movement of the walls of the face throttle causes an additional circumferential and radial flow, which subsequently leads to the additional hydrodynamic pressure components. The paper analyses viscous incompressible fluid flow in the face throttle of an automatic balancing device taking into account the axial and angular displacements of throttle’s surfaces and the inertia component of the fluid. The effect of local hydraulic losses as well as random changes in the coefficients of local hydraulic resistance at the inlet and outlet of the throttle is analysed.

Interactions Between Vortex-Induced Vibration of a Spring-Supported Cylinder and Fluid Flow in a Narrow Channel

2002 ◽  
Author(s):  
Masahito Nakano ◽  
Shinichi Maruyama ◽  
Hideyuki Mihira ◽  
Masatsugu Yoshizawa
Keyword(s):  
Reynolds Number ◽  
Fluid Flow ◽  
Narrow Channel ◽  
Simultaneous Equations ◽  
Nonlinear Interactions ◽  
Two Dimensional ◽  
Vortex Induced Vibration ◽  
Incompressible Viscous Flow ◽  
Unsteady Fluid Flow ◽  
Unsteady Fluid

This paper studies the nonlinear interactions between vortex-induced vibration of a spring-supported circular cylinder and the unsteady fluid flow in a narrow channel. The analytical model consists of two-dimensional incompressible viscous flow in a narrow channel at low Reynolds number, and the spring-supported cylinder that can move perpendicular to the wall of the channel. The marker-and-cell (MAC) method is used to calculate numerically the simultaneous equations governing the interaction between the motion of the cylinder and the unsteady fluid flow. Furthermore the numerical results are confirmed by experiments presented herein.

Enhanced thermal and fluid flow performance of cross flow tube bank with perforated splitter plate

2020 ◽  
pp. 1-13 ◽  
Author(s):  
Ankit Choudhary ◽  
Manoj Kumar ◽  
Anil Kumar Patil ◽  
Sunil Chamoli
Keyword(s):  
Fluid Flow ◽  
Cross Flow ◽  
Splitter Plate ◽  
Flow Tube ◽  
Tube Bank
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