Oscillating Flow in Ducts of Arbitrary Cross Section

1969 ◽  
Vol 73 (706) ◽  
pp. 894-896
Author(s):  
A. M. Abu-Sitta ◽  
D. G. Drake
Keyword(s):  
Boundary Layer ◽  
Viscous Fluid ◽  
Pressure Gradient ◽  
Numerical Solution ◽  
Cross Section ◽  
Circular Cross Section ◽  
Arbitrary Cross Section ◽  
Oscillating Flow ◽  
Elliptic Case ◽  
Uniform Cross Section

The rectilinear flow of an incompressible viscous fluid along a duct of uniform cross section due to an oscillating pressure gradient has been considered by a number of investigators. The duct of circular cross .section has been treated by Richardson and Tyler and Sexl, the elliptic case by Khamrui, and the rectangular case by Drake and Fan and Chao. Recently Jeng has discussed the importance of this type of flow and has given a procedure for calculating a numerical solution for a duct of arbitrary cross-section. An interesting feature of these flows is that, at large frequencies when the flow is of boundary-layer type, the velocity at any instant has its maximum near the walls, the velocity overshooting its almost uniform distribution at the centre of the duct.

A Method for Designing Wind Tunnel Contractions

1951 ◽  
Vol 55 (483) ◽  
pp. 169-180 ◽  
Author(s):  
R. Harrop
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Pressure Gradient ◽  
Cross Section ◽  
Incompressible Flow ◽  
Circular Cross Section ◽  
Flow Theory ◽  
Boundary Layer Separation ◽  
Experimental Results ◽  
Pressure Gradients

SummaryThe contraction of a wind tunnel should be free from adverse pressure gradients, since this might cause boundary layer separation.A wall contour has been designed for a circular cross-section contraction using incompressible flow theory. This gave a favourable pressure gradient at the beginning of the contraction where separation is likely to occur.Appendix I compares the theory with experimental results obtained from a model of a proposed supersonic tunnel of which the contraction is rectangular in cross-section and which has been based on the results obtained in this report.

Torsion of Composite Elastic Bars of Arbitrary Cross Section

1968 ◽  
Vol 90 (3) ◽  
pp. 435-440 ◽  
Author(s):  
E. M. Sparrow ◽  
H. S. Yu
Keyword(s):  
Exact Solution ◽  
Closed Form ◽  
Elastic Properties ◽  
Cross Section ◽  
Excellent Agreement ◽  
Solution Method ◽  
Circular Cross Section ◽  
High Accuracy ◽  
Arbitrary Cross Section ◽  
Closed Form Solutions

A method of analysis is presented for determining closed-form solutions for torsion of inhomogeneous prismatic bars of arbitrary cross section, the inhomogeneity stemming from the layering of materials of different elastic properties. It is demonstrated that the solution method is very easy to apply and provides results of high accuracy. As an application, solutions are obtained for the torsion of a bar of circular cross section consisting of two materials separated by a plane interface. The results are compared with those of various limiting cases and excellent agreement is found to exist. Among the limiting cases, an exact solution was derived by Green’s functions for the problem in which the interface between the materials coincides with a diameter of the circular cross section.

scholarly journals CFD Investigation of Fluid Flow Over Aerofoil With and Without Dimple

2020 ◽  
Author(s):  
Uzair Sajjad ◽  
Khalid Hamid ◽  
Naseem Abbas
Keyword(s):  
Boundary Layer ◽  
Fluid Flow ◽  
Cross Section ◽  
Turbulence Model ◽  
Aerodynamic Performance ◽  
3D Analysis ◽  
Cad Model ◽  
Uniform Cross Section ◽  
Solid Works ◽  
Lift And Drag

Abstract This work labels the effect of dimples on aerodynamic performance of an airfoil. NACA 0018 having a uniform cross section has been evaluated in this study. Eclipse dimpled airfoil is tested and compared with plain airfoil and with the airfoil in the literature [23,24]. Flows taken into consideration are subsonic. The CAD model is drawn in Solid works 2016, while the simulations are performed in Ansys 18.3. A 2-D CFD investigation is performed on both models using k-w turbulence model, subsequently the better one is selected based on the results. 3D analysis is performed on a segment of airfoil having one dimple. Lift and drag coefficients are calculated for various angles of attack. This investigation tells that dimples affect the aerodynamics of airfoil, particularly for various angle of attacks. For smaller angle of attacks, plain airfoil showed less drag and higher lift, but totally different trend is achieved with increasing angle of attack whereas 20° was found to be the optimum angle. The findings proved that dimples on the surface delay the separation of boundary layer by generating additional turbulence on the surface and consequently reduce the formation of wake, which in turn decreases drag significantly.

Magnetohydrodynamic pipe flow Part2. High Hartmann number

1962 ◽  
Vol 13 (4) ◽  
pp. 513-518 ◽  
Author(s):  
J. A. Shercliff
Keyword(s):  
Magnetic Fields ◽  
Pressure Gradient ◽  
Cross Section ◽  
Pipe Flow ◽  
Hartmann Number ◽  
Gradient Flow ◽  
Transverse Magnetic ◽  
Arbitrary Cross Section ◽  
Conducting Liquid ◽  
Experimental Pressure

The paper presents an improved, second approximation for the laminar motion of a conducting liquid at high Hartmann number in non-conducting pipes of arbitrary cross-section under uniform transverse magnetic fields. A satisfactory comparison with the author's previously experimental pressure gradient/flow results is made for the case of a circular pipe.

Pressure Distributions in Porous Ducts of Arbitrary Cross Section

1973 ◽  
Vol 95 (3) ◽  
pp. 342-348 ◽  
Author(s):  
J. C. P. Huang ◽  
H. S. Yu
Keyword(s):  
Pressure Gradient ◽  
Cross Section ◽  
Cross Sections ◽  
Porous Plate ◽  
Porous Wall ◽  
Design Criterion ◽  
Arbitrary Cross Section ◽  
Solid Particles ◽  
Equivalent Diameter ◽  
Pressure Distributions

A general analytical method has been developed to approximate the pressure distribution along a porous duct of an arbitrary cross section with uniform fluid extraction or addition through the wall. Application of this method is made to a variety of cross sections including circular tubes, parallel plate channels, elliptical ducts, rectangular ducts, annular ducts, and isosceles triangular ducts. Comparisons have been made with results from existing literature on cases of the circular porous tube and the parallel porous plate channel in which exact solutions are available. A numerical solution for the case of a parallel channel consisting of an impermeable wall on one side and a porous wall on the other side is also presented. One important filter duct design criterion has been found for each of the above cases. At a critical wall Reynolds number, defined by flow velocity normal to the wall and the equivalent diameter of the duct, the pressure gradient along the filter duct approaches zero. The zero pressure gradient in a filter duct ensures uniform filtration of solid particles.

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