Spurious Far-Field-Boundary Induced Drag in Two-Dimensional Flow Simulations

2011 ◽  
Vol 48 (4) ◽  
pp. 1444-1455 ◽  
Author(s):  
Daniel Destarac
Keyword(s):  
Far Field ◽  
Two Dimensional ◽  
Field Boundary ◽  
Flow Simulations ◽  
Dimensional Flow ◽  
Induced Drag ◽  
Two Dimensional Flow

Steady two-dimensional viscous flow in a jet

1972 ◽  
Vol 55 (1) ◽  
pp. 49-63 ◽  
Author(s):  
K. Capell
Keyword(s):  
Point Source ◽  
Viscous Flow ◽  
Closed Form ◽  
Stream Function ◽  
Asymptotic Expansions ◽  
Far Field ◽  
Two Dimensional ◽  
Complete Structure ◽  
Dimensional Flow ◽  
Two Dimensional Flow

An idealized two-dimensional flow due to a point source ofxmomentum is discussed. In the far field the flow is modelled by a jet region of large vorticity outside which the flow is potential. After use of the transformation\[ \zeta^3 = (\xi + i\eta)^3 = x + iy, \]the equations suggest naively obvious asymptotic expansions for the stream function in these two regions, namely\[ \sum_{n=0}^{\infty}\xi^{1-n}f_n(\eta)\quad {\rm and}\quad\sum_{n=0}^{\infty}\xi^{1-n}F_n(\eta/\xi) \]respectively. Consistency in matching these expansions is achieved by including logarithmic terms associated with the occurrence of eigensolutions.Fnis easy to find andJncan be found in closed form so the inner and outer eigensolutions may be fully determined along with the complete structure of the expansions.

CFD High L/D Riser Modeling Study

2007 ◽  
Author(s):  
Yiannis Constantinides ◽  
Owen H. Oakley ◽  
Samuel Holmes
Keyword(s):  
Fluid Flow ◽  
Computer Technology ◽  
Deep Water ◽  
Structural Model ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Flow Simulations ◽  
Dimensional Flow ◽  
Two Dimensional Flow ◽  
Good Agreement

Fully three dimensional fluid flow simulations are used with a simple structural model to simulate very long risers. This method overcomes many shortcomings of methodologies based on two dimensional flow simulations and can correctly include the effects of three dimensional structures such as strakes, buoyancy modules and catenary riser shapes. The method is benchmarked against laboratory and offshore experiments with model risers of length to diameter ratios up to 4,000. RMS values of vortex induced vibration motions are shown to be in good agreement with measurements. The resources needed to model ultra deep water drilling and production risers are estimated based on current computer technology.

scholarly journals Two-dimensional Flow Simulations around a Square Prism with Rounded Corners

1998 ◽  
Vol 1 ◽  
pp. 649-654
Author(s):  
Shin-ichi KAWAMURA ◽  
Yoshinobu KUBO ◽  
Eiki YAMAGUCHI
Keyword(s):  
Two Dimensional ◽  
Flow Simulations ◽  
Dimensional Flow ◽  
Square Prism ◽  
Two Dimensional Flow

scholarly journals On the drag of an aerofoil for two-dimensional flow

1926 ◽  
Vol 111 (759) ◽  
pp. 592-603
Keyword(s):  
Wind Tunnel ◽  
Good Accuracy ◽  
Unit Length ◽  
Two Dimensional ◽  
Head Losses ◽  
Dimensional Flow ◽  
Induced Drag ◽  
Total Head ◽  
Sufficient Distance ◽  
Two Dimensional Flow

(1) According to modern aerofoil theory, the drag of an aerofoil of finite span is compounded of two parts, one a profile drag associated with the shape and attitude of the section, and the other an induced drag connected with the variation of lift along the span. The magnitude of this induced drag can be determined when the forces acting on the aerofoil are known. As the span increases, the profile drag per unit length approaches a limiting value, whereas the induced drag becomes relatively smaller, because of the more uniform distribution of lift, and would disappear completely if the span were infinite. The present paper deals exclusively with the profile drag of an aerofoil of infinite span, or, in other words, the drag for two-dimensional flow. L. W. Bryant and D. H. Williams have shown from explorations of velocity in the wake of an aerofoil mounted between the walls of a wind tunnel, that the flow around the central part of the aerofoil, at a sufficient distance from the walls, is, for all practical purposes, two-dimensional. In an Appendix to the above paper, Prof. G. I. Taylor shows that there is good reason to believe, on theoretical grounds, that the drag of an aerofoil can be determined with good accuracy from observation of total-head losses in the wake, provided that these observations are taken in a region where the velocity disturbances are relatively small, that is, at a sufficient distance behind the aerofoil. The present investigation has been undertaken to examine experimentally this method of measuring drag, and also to throw light, in a general manner, on some characteristics of the wake. The experiments were made on an aerofoil of 0·5 foot chord mounted in a 4-foot wind tunnel, with small clearances between the tips and the tunnel walls (0·15 inches). Preliminary observations of total head showed that the wake was uniform along the span, except in the neighbourhood of the walls, where it opened out appreciably. To establish the fact that the drag could be determined from the total-head losses, observations—for 0° incidence—were taken in the wake at several sections, chiefly near the aerofoil tips. The drag of the entire aerofoil was then estimated from the integral along the span of the losses at each section. This value of the drag was found to be in close agreement with that measured directly on a balance, and it was concluded that the drag for two-dimensional flow could be estimated with good accuracy from the measurements of the total-head losses in the wake behind the median section.

Two-Dimensional Flow of Polymer Solutions Through Porous Media

1999 ◽  
Vol 2 (3) ◽  
pp. 251-262
Author(s):  
P. Gestoso ◽  
A. J. Muller ◽  
A. E. Saez
Keyword(s):  
Porous Media ◽  
Polymer Solutions ◽  
Two Dimensional ◽  
Dimensional Flow ◽  
Two Dimensional Flow

STUDY OF NON-ISOTHERMAL TWO-DIMENSIONAL FLOW OVER A SQUARE CYLINDER IMMERSED IN A CHANNEL

2019 ◽  
Author(s):  
Gabriel Machado dos Santos ◽  
Ítalo Augusto Magalhães de Ávila ◽  
Hélio Ribeiro Neto ◽  
João Marcelo Vedovoto
Keyword(s):  
Two Dimensional ◽  
Square Cylinder ◽  
Dimensional Flow ◽  
Two Dimensional Flow
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