Numerical Study of Boundary Layers With Reverse Wedge Flows Over a Semi-Infinite Flat Plate

2009 ◽  
Vol 77 (2) ◽  
Author(s):  
R. Ahmad ◽  
K. Naeem ◽  
Waqar Ahmed Khan
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Numerical Study ◽  
Boundary Layer Equation ◽  
Wedge Angle ◽  
Adverse Pressure Gradient ◽  
Problem Solution ◽  
Weighted Residual Method ◽  
Boundary Layer Problem ◽  
Layer Problem

This paper presents the classical approximation scheme to investigate the velocity profile associated with the Falkner–Skan boundary-layer problem. Solution of the boundary-layer equation is obtained for a model problem in which the flow field contains a substantial region of strongly reversed flow. The problem investigates the flow of a viscous liquid past a semi-infinite flat plate against an adverse pressure gradient. Optimized results for the dimensionless velocity profiles of reverse wedge flow are presented graphically for different values of wedge angle parameter β taken from 0≤β≤2.5. Weighted residual method (WRM) is used for determining the solution of nonlinear boundary-layer problem. Finally, for β=0 the results of WRM are compared with the results of homotopy perturbation method.

Thermal Turbulent Boundary Layer Under Strong Adverse Pressure Gradient Near Separation

1982 ◽  
Vol 104 (3) ◽  
pp. 397-402 ◽  
Author(s):  
N. Afzal
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Thermal Boundary Layer ◽  
Adverse Pressure Gradient ◽  
Power Laws ◽  
Wall Layer ◽  
Pressure Gradients ◽  
Boundary Layer Problem ◽  
Half Power ◽  
Layer Problem

The problem of the thermal turbulent boundary layer under the influence of strong adverse pressure gradients near separation is analysed by the method of matched asymptotic expansions. The limit corresponding to the neighborhood of separation, as formulated by Afzal [3], is employed. The thermal boundary layer problem is analysed using the appropriate inner and outer expansions (both above the thermal wall layer). It is found by matching that there exists an inertial sublayer where temperature distribution obeys the inverse half power laws. The comparison of the theory with the measurement shows that the slope and intercept of the wall (inner) law may be regarded as universal numbers, whereas the intercept of outer law shows a linear dependence on τw/δpx.

On a Boundary Layer Problem

2002 ◽  
Vol 108 (4) ◽  
pp. 369-398 ◽  
Author(s):  
R. Wong ◽  
Heping Yang
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Problem ◽  
Layer Problem

Effect of plasma actuator in boundary layer on flat plate model with turbulent promoter

2017 ◽  
Vol 232 (16) ◽  
pp. 3001-3010
Author(s):  
James Julian ◽  
Harinaldi ◽  
Budiarso ◽  
Chin-Cheng Wang ◽  
Ming-Jyh Chern
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Aerodynamic Drag ◽  
Active Flow Control ◽  
Adverse Pressure Gradient ◽  
Plasma Actuator ◽  
Experimental Results ◽  
Plate Model ◽  
Displacement Thickness ◽  
Turbulent Promoter

This paper shows experimental results for velocity measurement in the boundary layer with the use of a flat plate model. The flat plate model is disrupted with a wire trip and the effect of the plasma actuator to alter the flow in the boundary layer is then observed. The purpose of this research is to characterize the performance of the plasma actuator in a no-flow condition and with the use of a 2 m/s flow and also to theoretically analyze the performance of actuator in the boundary layer namely, displacement thickness, momentum thickness, and energy thickness. This is all done to acquire a deeper understanding of the capabilities of plasma actuator as one of the alternative active flow control equipment and to increase the effect of aerodynamic drag reduction. One of the ways to decrease the aerodynamic drag is to manipulate the flow to have a low boundary layer thickness value in order to prevent an adverse pressure gradient from happening, which then may lead to the formation of a flow separation. From experimental results, it is known that plasma actuator could decrease the thickness of the boundary layer by 9 mm.

The boundary layer over an impulsively started flat plate

1969 ◽  
Vol 310 (1502) ◽  
pp. 401-414 ◽  
Keyword(s):  
Boundary Layer ◽  
Leading Edge ◽  
Surface Shear Stress ◽  
Unsteady State ◽  
Similarity Condition ◽  
Surface Shear ◽  
Boundary Layer Problem ◽  
Independent Variables ◽  
Selection Of ◽  
Layer Problem

A numerical solution has been obtained for the development of the flow from the initial unsteady state described by Rayleigh to the ultimate steady state described by Blasius. The usual formulation of the problem in two independent variables is dropped, and three independent variables, in space and time, are reverted to. The boundary-layer problem is unconventional in that the boundary conditions are not completely known. Instead, it is known that the solution should satisfy a similarity condition, and use is made of this to obtain a solution by iteration. A finite-difference technique of a mixed, explicit-implicit, type is employed. The iteration converges rapidly. It is terminated where the maximum errors are estimated to be about 0.04%. A selection of the results for the velocity profiles and the surface shear stress is presented. One striking feature is the rapidity of the transition from the Rayleigh to the Blasius state. The change is practically complete, at a given station on the plate, by the time the plate has moved a distance equal to four times the distance from the station to the leading edge of the plate.

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