Vortical structures of supersonic flow over a delta-wing on a flat plate

2013 ◽  
Vol 102 (6) ◽  
pp. 061911 ◽  
Author(s):  
D. P. Wang ◽  
Z. X. Xia ◽  
Y. X. Zhao ◽  
Q. H. Wang ◽  
B. Liu
Keyword(s):  
Supersonic Flow ◽  
Flat Plate ◽  
Delta Wing ◽  
Vortical Structures

Surface pressures on a wing moving with supersonic speed

1974 ◽  
Vol 341 (1625) ◽  
pp. 177-193 ◽  
Keyword(s):  
Supersonic Flow ◽  
Delta Wing ◽  
Leading Edge ◽  
Ideal Gas ◽  
Numerical Results ◽  
Coordinate Surface ◽  
Supersonic Speed ◽  
Extrapolation Procedure ◽  
Specific Heats ◽  
Limiting Values

Estimates for pressures on the surface of a given delta wing at zero incidence in a steady uniform stream of air are obtained by numerically integrating two semi-characteristic forms of equations which govern the inviscid supersonic flow of an ideal gas with constant specific heats. In one form of the equations coordinate surfaces are fixed in space so that the surface of the wing, which has round sonic leading edges, is a coordinate surface. In the other, two families of coordinates are chosen to be stream-surfaces. For each form of the equations, a finite difference method has been used to compute the supersonic flow around the wing. Convergence of the numerical results, as the mesh is refined, is slow near the leading edge of the wing and an extrapolation procedure is used to predict limiting values for the pressures on the surface of the wing at two stations where theoretical and experimental results have been given earlier by another worker. At one station differences between the results given here and the results given earlier are significant. The two methods used here produce consistent values for the pressures on the surface of the wing and, on the basis of this numerical evidence together with other cited numerical results, it is concluded that the pressures given here are close to the true theoretical values.

Characterization of the Surface Curvature Effect Using LES for a Single Round Impinging Jet

2017 ◽  
Author(s):  
Pierre Aillaud ◽  
Florent Duchaine ◽  
Laurent Gicquel ◽  
Sheddia Didorally
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Temporal Distribution ◽  
Impinging Jet ◽  
Ambient Air ◽  
Surface Curvature ◽  
Flow Topology ◽  
Reference Case ◽  
Vortical Structures ◽  
Eddy Simulation

In this paper, wall resolved Large Eddy Simulation is used to study the effect of the surface curvature for two impinging jet configurations. The reference case is a single round jet impinging on a flat plate at a Reynolds number (based on the bulk velocity Ub and the pipe diameter D) Re = 23 000 and for a nozzle to plate distance H = 2D. The results on this configuration have been previously analyzed and validated against experimental results. This paper compares for the same operating point, the flat plate impingement to an impinging jet on a concave hemispherical surface with a relative curvature d/D = 0.089 where d is the concave surface diameter. Mean and Root Mean Square (RMS) quantities are compared to highlight differences and similarities between the two cases. In addition high order statistic such as Skewness of the temporal distribution of wall heat flux is analyzed. Probability density functions (PDF) are also built to further characterize the effect of surface curvature. It is shown that the surface curvature has a destabilizing effect on the vortical structures present in such a flow leading to a modification of the wall heat transfer compared to the flat plate case. The flow topology in the concave case is dominated by a large toroidal stationary vortex. This vortex generates a natural confinement that causes the increase of the mean temperature of the ambient air around the jet. The main effect is the reduction of the capacity of the vortical structures to enhance heat transfer. Finally, the confinement effect combined with the destabilization due to the concave curvature lead to an alleviation of the secondary peak in the Nusselt distribution and a reduction of the heat transfer at the wall.

Stability of a wake behind a flat plate in a supersonic flow

1995 ◽  
Vol 36 (6) ◽  
pp. 844-847
Author(s):  
V. I. Lysenko ◽  
N. V. Semenov
Keyword(s):  
Supersonic Flow ◽  
Flat Plate

Unsteady Simulations for an Advanced-Louver Cooling Scheme

2008 ◽  
Author(s):  
Chad X.-Z. Zhang ◽  
Sung In Kim ◽  
Ibrahim G. Hassan
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Flat Plate ◽  
Flow Velocity ◽  
Detached Eddy Simulation ◽  
Computer Cluster ◽  
Vortical Structures ◽  
Eddy Simulation ◽  
Mainstream Flow ◽  
Adiabatic Effectiveness

The performance of a louver cooling scheme on a flat plate was analyzed using Detached Eddy Simulation. It was assumed that the louver cooling scheme was tested in a wind tunnel with the mainstream flow velocity of 20 m/s, equivalent to a Reynolds number of 16200 based on the jet diameter. Turbulence closure was achieved by a Realizable k-ε based DES turbulence model. Solutions of two blowing ratios of 0.5 and 1 were successfully obtained by running parallel on 16 nodes on a computer cluster. The instantaneous flow fields were found to be highly unsteady and oscillatory in nature. It is shown that the fluctuations in the adiabatic effectiveness are mainly caused by the spanwise fluctuation of the coolant jet and the unsteady vortical structures created by the interaction of the jet and the mainstream.

Development of a three-dimensional free shear layer

1998 ◽  
Vol 369 ◽  
pp. 49-89 ◽  
Author(s):  
A. J. RILEY ◽  
M. V. LOWSON
Keyword(s):  
Shear Layer ◽  
Flow Instability ◽  
Delta Wing ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Transition To Turbulence ◽  
Free Shear Layer ◽  
Velocity Data ◽  
Sweep Angle ◽  
Vortical Structures

Experiments have been undertaken to characterize the flow field over a delta wing, with an 85° sweep angle, at 12.5° incidence. Application of a laser Doppler anemometer has enabled detailed three-dimensional velocity data to be obtained within the free shear layer, revealing a system of steady co-rotating vortical structures. These sub-vortex structures are associated with low-momentum flow pockets in the separated vortex flow. The structures are found to be dependent on local Reynolds number, and undergo transition to turbulence. The structural features disappear as the sub-vortices are wrapped into the main vortex core. A local three-dimensional Kelvin–Helmholtz-type instability is suggested for the formation of these vortical structures in the free shear layer. This instability has parallels with the cross-flow instability that occurs in three-dimensional boundary layers. Velocity data at high Reynolds numbers have shown that the sub-vortical structures continue to form, consistent with flow visualization results over fighter aircraft at flight Reynolds numbers.

Note on the Extension of Evvard’s Method to Wings with Subsonic Leading Edges Moving at Supersonic Speeds

1957 ◽  
Vol 8 (1) ◽  
pp. 87-102 ◽  
Author(s):  
G. J. Hancock
Keyword(s):  
Flat Plate ◽  
Delta Wing ◽  
Leading Edge ◽  
Wing Surface ◽  
List Type ◽  
Pressure Loading ◽  
Supersonic Speed ◽  
Triangular Wing ◽  
Finite Wing ◽  
The Relationship

SummaryEvvard’s technique is applied to the problem of a thin finite wing moving at a supersonic speed when the leading edge is subsonic. It is developed in two methods:—(i) in which the relationship between the pressure loading and the integrals of the downwash over the wing surface is extended as far as possible, and which has to be computed numerically;(ii) in which approximations are made for the upwash velocities in the neighbourhood of the leading edge, resulting in a series of standard integrals for the estimation of the pressure loading.Method (ii) is applied to the pressure loading on a flat plate triangular wing and cropped delta wing, and the application to more general shapes is discussed.

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