An inverse boundary-layer method for compressible laminar and turbulent boundary layers

1976 ◽  
Vol 13 (9) ◽  
pp. 709-717 ◽  
Author(s):  
Tuncer Cebeci
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Turbulent Boundary Layers ◽  
Inverse Boundary ◽  
Layer Method ◽  
Boundary Layer Method

A time-dependent approach for calculating steady inverse boundary-layer flows with separation

1983 ◽  
Vol 389 (1796) ◽  
pp. 171-178 ◽  
Keyword(s):  
Boundary Layer ◽  
Streamwise Velocity ◽  
Time Dependent ◽  
Steady Flows ◽  
Boundary Layer Flows ◽  
Inverse Boundary ◽  
Iteration Parameter ◽  
Layer Method ◽  
Boundary Layer Method ◽  
Box Method

In this paper we describe an unsteady inverse boundary-layer method that can be used to compute steady flows with separation. The method uses Keller’s box method with Cebeci’s Mechul function formulation. De­pending on the complexity of the flow, two versions of the box method are used. In regions of positive streamwise velocity component u , the regular box is used; in regions where u becomes negative (t > 0), the zigzag box is used. When t = 0, and u becomes negative in some region across the layer, the regular box with the FLARE approximation is used. Calculations per­formed with this approach indicate that the use of a time dependent inverse boundary-layer method in which time is used as an iteration parameter provides a good approach in improving the accuracy of the solutions obtained from the FLARE approximation.

scholarly journals Computation of unsteady turbulent boundary layers with flow reversal, and evaluation of two separate turbulence models

1982 ◽  
Vol 380 (1779) ◽  
pp. 291-304 ◽  
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Reynolds Shear Stress ◽  
Turbulence Models ◽  
Turbulent Boundary Layers ◽  
Laminar Flows ◽  
Flow Reversal ◽  
Test Cases ◽  
Boundary Layer Method ◽  
Stress Term

In this paper we extend the unsteady laminar boundary-layer method of Cebeci to turbulent boundary layers with flow reversal. Using the algebraic eddy-viscosity formulation of Cebeci and Smith, we consider several test cases to investigate the proposition that unsteady turbulent boundary layers also remain free of singularities. Since the accuracy of turbulent flow calculations also depends on the closure assumption for the Reynolds shear-stress term, we also perform calculations by using the turbulence model of Bradshaw, Ferriss and Atwell; we solve th e governing equations for both models by using the same numerical scheme and compare their predictions, restricting the comparisons to cases in which wall shear is positive. The study reveals that, as in laminar flows, the unsteady turbulent boundary layers seem to be free from singularities but there is a clear indication of rapid thickening of the boundary layer with increasing flow reversal. The study also reveals that the predictions of both turbulence models are the same for all practical purposes.

TRANSONIC AEROELASTIC ANALYSIS OF AIRCRAFT WINGS CONSIDERING THE BOUNDARY-LAYER EFFECTS

2009 ◽  
Vol 23 (03) ◽  
pp. 473-476
Author(s):  
JONG-YUN KIM ◽  
KYUNG-SEOK KIM ◽  
SEUNG-JUN LEE ◽  
IN LEE
Keyword(s):  
Boundary Layer ◽  
Viscous Flows ◽  
Small Disturbance ◽  
Viscous Effects ◽  
Inverse Boundary ◽  
Aircraft Wings ◽  
Layer Method ◽  
Aeroelastic Analysis ◽  
Boundary Layer Method ◽  
Interaction Approach

Aerodynamic solver using the transonic small-disturbance (TSD) equation has frequently been used to perform practical aeroelastic analysis for many aircraft models. In the present study, the more accurate aeroelastic analysis solver using the TSD equation was developed by considering the viscous effects of the boundary-layer. The viscous effects were considered using Green's lag-entrainment equations and an inverse boundary-layer method. Through aerodynamic analyses for several aircraft wings, the viscous-inviscid interaction approach could improve the accuracy of the aerodynamic computation using the TSD equation. Finally, the aeroelastic characteristics were investigated using comparisons of the time responses between the inviscid and viscous flows.

The Departure from Equilibrium of Turbulent Boundary Layers

1968 ◽  
Vol 19 (1) ◽  
pp. 1-19 ◽  
Author(s):  
H. McDonald
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Kinetic Energy ◽  
Stress Distribution ◽  
Boundary Layers ◽  
Turbulent Boundary Layers ◽  
Two Dimensional ◽  
Pressure Distributions ◽  
Momentum Integral ◽  
State Examination

SummaryRecently two authors, Nash and Goldberg, have suggested, intuitively, that the rate at which the shear stress distribution in an incompressible, two-dimensional, turbulent boundary layer would return to its equilibrium value is directly proportional to the extent of the departure from the equilibrium state. Examination of the behaviour of the integral properties of the boundary layer supports this hypothesis. In the present paper a relationship similar to the suggestion of Nash and Goldberg is derived from the local balance of the kinetic energy of the turbulence. Coupling this simple derived relationship to the boundary layer momentum and moment-of-momentum integral equations results in quite accurate predictions of the behaviour of non-equilibrium turbulent boundary layers in arbitrary adverse (given) pressure distributions.

Aero-optics of subsonic turbulent boundary layers

2012 ◽  
Vol 696 ◽  
pp. 122-151 ◽  
Author(s):  
Kan Wang ◽  
Meng Wang
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Boundary Layers ◽  
Dominant Role ◽  
Elevation Angle ◽  
Turbulent Boundary Layers ◽  
Density Field ◽  
Small Scale ◽  
Number Range ◽  
Scale Turbulence

AbstractCompressible large-eddy simulations are carried out to study the aero-optical distortions caused by Mach 0.5 flat-plate turbulent boundary layers at Reynolds numbers of ${\mathit{Re}}_{\theta } = 875$, 1770 and 3550, based on momentum thickness. The fluctuations of refractive index are calculated from the density field, and wavefront distortions of an optical beam traversing the boundary layer are computed based on geometric optics. The effects of aperture size, small-scale turbulence, different flow regions and beam elevation angle are examined and the underlying flow physics is analysed. It is found that the level of optical distortion decreases with increasing Reynolds number within the Reynolds-number range considered. The contributions from the viscous sublayer and buffer layer are small, while the wake region plays a dominant role, followed by the logarithmic layer. By low-pass filtering the fluctuating density field, it is shown that small-scale turbulence is optically inactive. Consistent with previous experimental findings, the distortion magnitude is dependent on the propagation direction due to anisotropy of the boundary-layer vortical structures. Density correlations and length scales are analysed to understand the elevation-angle dependence and its relation to turbulence structures. The applicability of Sutton’s linking equation to boundary-layer flows is examined, and excellent agreement between linking equation predictions and directly integrated distortions is obtained when the density length scale is appropriately defined.

Boundary layer method in the problem of far propagation of surface SV-waves

2011 ◽  
Vol 175 (6) ◽  
pp. 651-671
Author(s):  
N. Ya. Kirpichnikova ◽  
A. S. Kirpichnikova
Keyword(s):  
Boundary Layer ◽  
Layer Method ◽  
Boundary Layer Method
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