scholarly journals Asymptotic scaling of drag in flat-plate turbulent boundary layers

2020 ◽  
Vol 32 (4) ◽  
pp. 041702 ◽  
Author(s):  
Shivsai Ajit Dixit ◽  
Abhishek Gupta ◽  
Harish Choudhary ◽  
A. K. Singh ◽  
Thara Prabhakaran
Keyword(s):  
Flat Plate ◽  
Boundary Layers ◽  
Turbulent Boundary Layers ◽  
Asymptotic Scaling

Use of k−ε−γ Model to Predict Intermittency in Turbulent Boundary-Layers

2000 ◽  
Vol 122 (3) ◽  
pp. 542-546 ◽  
Author(s):  
Anupam Dewan ◽  
Jaywant H. Arakeri
Keyword(s):  
Boundary Layer ◽  
Kinetic Energy ◽  
Pressure Gradient ◽  
Flat Plate ◽  
Turbulent Kinetic Energy ◽  
Boundary Layers ◽  
Turbulent Boundary Layers ◽  
Rate Of Dissipation ◽  
Dissipation Equation ◽  
Averaged Model

The intermittency profile in the turbulent flat-plate zero pressure-gradient boundary-layer and a thick axisymmetric boundary-layer has been computed using the Reynolds-averaged k−ε−γ model, where k denotes turbulent kinetic energy, ε its rate of dissipation, and γ intermittency. The Reynolds-averaged model is simpler compared to the conditional model used in the literature. The dissipation equation of the Reynolds-averaged model is modified to account for the effect of entrainment. It has been shown that the model correctly predicts the observed intermittency of the flows. [S0098-2202(00)02403-2]

Mean Velocity Scaling and Friction Coefficient Estimation for Rough Surface Turbulent Boundary Layers in Turbomachines

2014 ◽  
Author(s):  
Ju Hyun Shin ◽  
Seung Jin Song
Keyword(s):  
Flat Plate ◽  
Rough Surface ◽  
Boundary Layers ◽  
Turbine Blades ◽  
Axial Compressor ◽  
Turbulent Boundary Layers ◽  
Flat Plates ◽  
Mean Velocity ◽  
Coefficient Estimation ◽  
Compressor And Turbine Blades

Based on flat plate results, mean velocity and friction coefficient estimation methods are proposed for rough surface turbulent boundary layers on axial compressor and turbine blades. The ratio of the displacement thickness to boundary layer thickness (δ*/δ) was first suggested by Zagarola and Smits (1998) for smooth pipe flows. The same parameter is proposed in this paper to scale the normalized mean velocity defect of smooth and rough surface flat plate turbulent boundary layers with zero, favorable, and adverse pressure gradients. The available mean velocity defect profiles of smooth and rough surface boundary layers from axial compressor and turbine blades are also scaled and compared to the flat plate results. Irrespective of the Reynolds number (Reθ), pressure gradient (K), and roughness (k), δ*/δ provides appropriate scaling for collapsing the flat plate and turbomachinery data. From the results, a new one-variable power law based on δ*/δ is proposed to estimate the mean velocity profile. The proposed power law can accurately estimate boundary layers on flat plates, compressor blades, and turbine blades. Finally, a new empirical Cf correlation is proposed for rough surface turbulent boundary layers under pressure gradients. The proposed Cf correlation is based on that of Bergstrom et al. (2005) and newly incorporates the acceleration parameter K. It can accurately estimate Cf in turbulent boundary layers of rough surface flat plates as well as those of smooth turbine blades.

A Study on Turbulent Boundary Layers on a Smooth Flat Plate in an Open Channel

2001 ◽  
Vol 123 (2) ◽  
pp. 394-400 ◽  
Author(s):  
Ram Balachandar ◽  
D. Blakely ◽  
M. Tachie ◽  
G. Putz
Keyword(s):  
Flat Plate ◽  
Froude Number ◽  
Boundary Layers ◽  
Open Channel ◽  
Reynolds Numbers ◽  
Turbulent Boundary Layers ◽  
Wall Region ◽  
Mean Velocity ◽  
Number Range ◽  
High Reynolds

An experimental study was undertaken to investigate the characteristics of turbulent boundary layers developing on smooth flat plate in an open channel flow at moderately high Froude numbers (0.25<Fr<1.1) and low momentum thickness Reynolds numbers 800<Reθ<2900. The low range of Reynolds numbers and the high Froude number range make the study important, as most other studies of this type have been conducted at high Reynolds numbers and lower Froude numbers (∼0.1). Velocity measurements were carried out using a laser-Doppler anemometer equipped with a beam expansion device to enable measurements close to the wall region. The shear velocities were computed using the near-wall measurements in the viscous subregion. The variables of interest include the longitudinal mean velocity, the turbulence intensity, and the velocity skewness and flatness distributions across the boundary layer. The applicability of a constant Coles’ wake parameter (Π=0.55) to open channel flows has been discounted. The effect of the Froude number on the above parameters was also examined.

Comparison of Two Analyses of Boundary-Layer Data on a Flat Plate

1958 ◽  
Vol 2 (01) ◽  
pp. 21-33
Author(s):  
L. Landweber ◽  
T. T. Siao
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Boundary Layers ◽  
Turbulent Boundary Layers ◽  
Logarithmic Law

In a recent paper (1) it was indicated that there appeared to be a need for generalizing the well-known logarithmic law of turbulent boundary layers and such a generalization was derived on the basis of a suggestion due to Townsend (2). It was found that the logarithmic formulas constitute only one member of a family of possible formulas, among which that one which best fits the boundary-layer data should be selected.

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