Flat Plate Wing Standing on a Wall Covered with a Thick Boundary Layer. Wing Characteristics under the Effects of Side Wall Boundary Layer and Wing Tip Vortex.

AbstractSteady motion of a viscous incompressible fluid in a rotating circular cylinder with a sloping bottom is investigated at low Ekman number. The flow is driven by a lightly faster rotation of the top, and non-linear inertia terms are neglected.A solution is found for a shallow container of small bottom slope. The side-wall boundary layer is shown to have an almost axi-symmetric component as well as the asymmetric layer found by Pedlosky and Greenspan (3). A further asymmetry in the interior flow is produced by the presence of the second component of the side-wall boundary layer.

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Simulations of reflected-shock waves in shock tubes taking account of side-wall boundary-layer effects.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B ◽

10.1299/kikaib.56.3205 ◽

1990 ◽

Vol 56 (531) ◽

pp. 3205-3209 ◽

Cited By ~ 3

Author(s):

Yasunari TAKANO

Keyword(s):

Boundary Layer ◽

Shock Waves ◽

Side Wall ◽

Shock Tubes ◽

Reflected Shock ◽

Wall Boundary Layer ◽

Wall Boundary

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Ionizing argon boundary layers. Part 2. Shock-tube side-wall boundary-layer flows

Journal of Fluid Mechanics ◽

10.1017/s0022112079000409 ◽

1979 ◽

Vol 91 (4) ◽

pp. 679-696 ◽

Cited By ~ 6

Author(s):

W. S. Liu ◽

I. I. Glass

Keyword(s):

Boundary Layer ◽

Boundary Conditions ◽

Shock Tube ◽

Flat Plate ◽

Electron Number Density ◽

Side Wall ◽

Number Density ◽

Electron Number ◽

Wall Boundary ◽

Wall Boundary Conditions

A combined experimental and theoretical investigation was conducted on the shock-tube side-wall ionizing boundary-layer induced by a shock wave moving into argon. The dual-wavelength interferometric boundary-layer data were obtained by using a 23 cm diameter Mach—Zehnder interferometer with the 10 × 18 cm Hypervelocity Shock Tube at initial shock Mach numbers of 13 and 16, an initial pressure of 5 torr and a temperature of 300° K. The plasma density and electron number density in the boundary layer were measured and compared with numerical profiles obtained by using an implicit finite-difference scheme for a two-temperature, chemical non-equilibrium, laminar boundary-layer flow in ionizing argon. The analysis included the variations of transport properties based on elastic-scattering cross-sections, effects of chemical reactions, radiation-energy losses and electron-sheath wall boundary conditions. Considering the difficulties involved in such complex plasma flows, satisfactory agreement was obtained between the analyses and experiments. A comparison was made with the flat-plate case and despite the very different velocity boundary conditions at the wall for the two flows the experimental data appear to be quite similar. The experimental bump in the profile of electron number density which was found in the flat-plate case was not found in the side-wall case. Comparisons and discussions of the results for the different types of boundary layer are presented, including a comparison between experimentally derived and analytical plasma-temperature profiles.

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Large-Eddy Simulation of Wake and Boundary Layer Interactions Behind a Circular Cylinder

Journal of Fluids Engineering ◽

10.1115/1.3176982 ◽

2009 ◽

Vol 131 (9) ◽

Cited By ~ 14

Author(s):

S. Sarkar ◽

Sudipto Sarkar

Keyword(s):

Boundary Layer ◽

Circular Cylinder ◽

Flow Visualization ◽

Flat Plate ◽

Shear Layers ◽

Bypass Transition ◽

Wall Boundary Layer ◽

Wall Boundary ◽

Gap Ratio ◽

Large Eddy

Large-eddy simulations (LESs) of flow past a circular cylinder in the vicinity of a flat plate have been carried out for three different gap-to-diameter (G/D) ratios of 0.25, 0.5, and 1.0 (where G signifies the gap between the flat plate and the cylinder, and D signifies the cylinder diameter) following the experiment of Price et al. (2002, “Flow Visualization Around a Circular Cylinder Near to a Plane Wall,” J. Fluids Struct., 16, pp. 175–191). The flow visualization along with turbulent statistics are presented for a Reynolds number of Re=1440 (based on D and the inlet free-stream velocity U∞). The three-dimensional time-dependent, incompressible Navier–Stokes equations are solved using a symmetry-preserving finite-difference scheme of second-order spatial and temporal accuracy. The immersed-boundary method is employed to impose the no-slip boundary condition at the cylinder surface. An attempt is made to understand the physics of flow involving interactions of shear layers shed from the cylinder and the wall boundary layer. Present LES reveals the shear layer instability and formation of small-scale eddies apart from their mutual interactions with the boundary layer. It has been observed that G/D ratio has a large influence on the modification of wake dynamics and evolution of the wall boundary layer. For a low gap ratio, it is difficult to identify the boundary layer because of its strong interactions with the shear layers; however, a rapid transition to turbulence of the boundary layer, which is similar to bypass transition, is observed for a large gap ratio.

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Computational modeling of the flow in a wind tunnel

Aircraft Engineering and Aerospace Technology ◽

10.1108/aeat-05-2016-0072 ◽

2018 ◽

Vol 90 (1) ◽

pp. 175-185 ◽

Cited By ~ 1

Author(s):

Mahmood Khalid ◽

Khalid A. Juhany ◽

Salah Hafez

Keyword(s):

Boundary Layer ◽

Wind Tunnel ◽

Computational Modeling ◽

Stokes Equations ◽

Side Wall ◽

Simultaneous Application ◽

Content Type ◽

Wall Boundary Layer ◽

Wall Boundary ◽

Solid Walls

Purpose The purpose of this paper is to use a computational technique to simulate the flow in a two-dimensional (2D) wind tunnel where the effect of the solid walls facing the model has been addressed using a porous geometry so that interference arriving at the solid walls are duly damped and a flow suction procedure has been adopted at the side wall to minimize the span-wise effect of the growing side wall boundary layer. Design/methodology/approach A CFD procedure based on discretization of the Navier–Stokes equations has been used to model the flow in a rectangular volume with appropriate treatment for solid walls of the confined volume in which the model is placed. The rectangular volume was configured by stacking O-Grid sections in a span-wise direction using geometric growth from the wall. A porous wall condition has been adapted to counter the wall interference signatures and a separate suction procedure has been implemented for reducing the side wall boundary layer effects. Findings It has been shown that through such corrective measures, the flow in a wind tunnel can be adequately simulated using computational modeling. Computed results were compared against experimental measurements obtained from IAR (Institute for Aerospace, Canada) and NAL (National Aeronautical Laboratory, Japan) to show that indeed appropriate corrective means may be adapted to reduce the interference effects. Research limitations/implications The solutions seemed to converge a lot better using relatively coarser grids which placed the shock locations closer to the experimental values. The finer grids were more stiff to converge and resulted in reversed flow with the two equation k-w model in the region where the intention was to draw out the fluid to thin down the boundary layer. The one equation Spalart–Allmaras model gave better result when porosity and wall suction routines were implemented. Practical implications This method could be used by industry to point check the results against certain demanding flow conditions and then used for more routine parametric studies at other conditions. The method would prove to be efficient and economical during early design stages of a configuration. Originality/value The method makes use of an O-grid to represent the confined test section and its dual treatment of wall interference and blockage effects through simultaneous application of porosity and boundary layer suction is believed to be quite original.

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