Rotating elliptic cylinders in a viscous fluid at rest or in a parallel stream

1977 ◽  
Vol 79 (1) ◽  
pp. 127-156 ◽  
Author(s):  
Hans J. Lugt ◽  
Samuel Ohring
Keyword(s):  
Reynolds Number ◽  
Fluid Flow ◽  
Numerical Solutions ◽  
Elliptic Cylinder ◽  
The Body ◽  
Oscillatory Behaviour ◽  
Incompressible Fluid Flow ◽  
Transient Period ◽  
Parallel Stream ◽  
Rotating Bodies

Numerical solutions are presented for laminar incompressible fluid flow past a rotating thin elliptic cylinder either in a medium at rest at infinity or in a parallel stream. The transient period from the abrupt start of the body to some later time (at which the flow may be steady or periodic) is studied by means of streamlines and equi-vorticity lines and by means of drag, lift and moment coefficients. For purely rotating cylinders oscillatory behaviour from a certain Reynolds number on is observed and explained. Rotating bodies in a parallel stream are studied for two cases: (i) when the vortex developing at the retreating edge of the thin ellipse is in front of the edge and (ii) when it is behind the edge.

Laminar flow past an abruptly accelerated elliptic cylinder at 45° incidence

1974 ◽  
Vol 65 (4) ◽  
pp. 711-734 ◽  
Author(s):  
H. J. Lugt ◽  
H. J. Haussling
Keyword(s):  
Steady State ◽  
Numerical Solutions ◽  
Fluid Flows ◽  
Elliptic Cylinder ◽  
Finite Difference Schemes ◽  
Quasi Steady State ◽  
Constant Vorticity ◽  
Transient Period ◽  
Incompressible Fluid Flows ◽  
Steady State Solutions

Numerical solutions for laminar incompressible fluid flows past an abruptly started elliptic cylinder at 45° incidence are presented. Various finite-difference schemes for the stream-function/vorticity formulation are used and their merits briefly discussed. Almost steady-state solutions are obtained forRe= 15 and 30, whereas forRe= 200 a Kármán vortex street develops. The transient period from the start to the steady or quasi-steady state is investigated in terms of patterns of streamlines and lines of constant vorticity and drag, lift and moment coefficients.

Temporally- and Spatially-Periodic Laminar Flow and Heat Transfer in Staggered-Plate Arrays

2007 ◽  
Author(s):  
Alexandre Lamoureux ◽  
B. Rabi Baliga
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Fluid Flow ◽  
Numerical Solutions ◽  
Initial Conditions ◽  
Plate Thickness ◽  
Geometrical Parameters ◽  
Reduced Pressure ◽  
Flow And Heat Transfer ◽  
Spatially Periodic

A computational investigation of temporally- and spatially-periodic laminar two-dimensional fluid flow and heat transfer in staggered-plate arrays is presented in this paper. The objective and the novel aspect of this study is the investigation of the influence (on the numerical solutions) of including single and multiple representative geometric modules in the calculation domain, with spatially-periodic boundary conditions imposed on the instantaneous velocity and temperature fields in both the streamwise and the lateral directions. The following geometrical parameters, normalized with respect to a representative module height, were studied: a dimensionless plate length equal to 1, and a dimensionless plate thickness of 0.250. This relatively high value of dimensionless plate thickness, compared to those commonly encountered in rectangular offset-fin cores of compact heat exchangers, was deliberately chosen to induce and enhance the unsteady features of the fluid flow and heat transfer phenomena. Different specified values of the time-mean modular streamwise gradient of the reduced pressure were investigated, yielding values of Reynolds number (Kays and London definition) in the range of 100 to 625. The Prandtl number was fixed at 0.7. In the multiple-module simulations, for Reynolds number values exceeding 400, it was found that multiple solutions are possible: the particular solution which is obtained in any one simulation depends on the specified initial conditions. The results presented include time-mean modular friction factors, modular Colburn factors, and Strouhal numbers.

Accurate Numerical Prediction of Incompressible Fluid Flow in Lid-Driven Cavities

2011 ◽  
Vol 110-116 ◽  
pp. 4365-4372
Author(s):  
Abdul Munir Fudhail ◽  
Mohd Rody Mohamad Zin ◽  
Nor C. Sidik Azwadi ◽  
Mohd Azli Salim
Keyword(s):  
Reynolds Number ◽  
Fluid Flow ◽  
Aspect Ratio ◽  
Incompressible Fluid ◽  
Numerical Method ◽  
Stream Function ◽  
Numerical Experiments ◽  
Flow Behavior ◽  
Incompressible Fluid Flow ◽  
Primary Vortex

In this paper, we report an efficient numerical method to predict fluid flow behavior in a square and deep lid-driven cavities. The conventional continuity and momentum equations are transformed into stream-function and vorticity formulation to reduce the number of unknown spatial quantities. Numerical experiments were performed with different values of aspect ratio and Reynolds number to investigate the effect of these dimensionless parameters on the fluid flow behavior in the cavity. In the current study, we found that the dynamics and the structure of primary vortex are significantly affected by the Reynolds number and the aspect ratio of the cavity.

scholarly journals A numerical study of steady viscous flow past a circular cylinder

1980 ◽  
Vol 98 (4) ◽  
pp. 819-855 ◽  
Author(s):  
Bengt Fornberg
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Viscous Flow ◽  
Numerical Solutions ◽  
Numerical Study ◽  
Reynolds Numbers ◽  
Iteration Scheme ◽  
The Body ◽  
Flow Past ◽  
A New Technique

Numerical solutions have been obtained for steady viscous flow past a circular cylinder at Reynolds numbers up to 300. A new technique is proposed for the boundary condition at large distances and an iteration scheme has been developed, based on Newton's method, which circumvents the numerical difficulties previously encountered around and beyond a Reynolds number of 100. Some new trends are observed in the solution shortly before a Reynolds number of 300. As vorticity starts to recirculate back from the end of the wake region, this region becomes wider and shorter. Other flow quantities like position of separation point, drag, pressure and vorticity distributions on the body surface appear to be quite unaffected by this reversal of trends.

scholarly journals Movement of a finite body in channel flow

2016 ◽  
Vol 472 (2191) ◽  
pp. 20160164 ◽  
Author(s):  
Frank T. Smith ◽  
Edward R. Johnson
Keyword(s):  
Reynolds Number ◽  
Channel Flow ◽  
Flow Instability ◽  
Flow Direction ◽  
Finite Size ◽  
The Body ◽  
Thin Body ◽  
Shear Stresses ◽  
Unsteady Interaction ◽  
High Reynolds

A body of finite size is moving freely inside, and interacting with, a channel flow. The description of this unsteady interaction for a comparatively dense thin body moving slowly relative to flow at medium-to-high Reynolds number shows that an inviscid core problem with vorticity determines much, but not all, of the dominant response. It is found that the lift induced on a body of length comparable to the channel width leads to differences in flow direction upstream and downstream on the body scale which are smoothed out axially over a longer viscous length scale; the latter directly affects the change in flow directions. The change is such that in any symmetric incident flow the ratio of slopes is found to be cos ⁡ ( π / 7 ) , i.e. approximately 0.900969, independently of Reynolds number, wall shear stresses and velocity profile. The two axial scales determine the evolution of the body and the flow, always yielding instability. This unusual evolution and linear or nonlinear instability mechanism arise outside the conventional range of flow instability and are influenced substantially by the lateral positioning, length and axial velocity of the body.

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