Experimental determination of mixing length in the buffer layer of a turbulent boundary layer

1996 ◽  
Vol 12 (3) ◽  
pp. 298-304
Author(s):  
Eu.A. Gostev
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Experimental Determination ◽  
Buffer Layer ◽  
Mixing Length

A Model for Velocity Profile in Turbulent Boundary Layer with Drag Reducing Surfactants

2005 ◽  
Vol 15 (3) ◽  
pp. 152-159 ◽  
Author(s):  
A. Krope ◽  
J. Krope ◽  
L.C. Lipus
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Velocity Profile ◽  
General Problem ◽  
Frictional Resistance ◽  
Mixing Length ◽  
Mean Velocity ◽  
Pipe Section ◽  
Turbulent Water

Abstract A new model for mean velocity profile of turbulent water flow with added drag-reducing surfactants is presented in this paper. The general problem of drag due to frictional resistance is reviewed and drag reduction by the addition of polymers or surfactants is introduced. The model bases on modified Prandtl's mixing length hypothesis and includes three parameters, which depend on additives and can be evaluated by numerical simulation from experimental datasets. The advantage of the model in comparison with previously reported models is that it gives uniform curve for whole pipe section and can be determined for a new surfactant with less necessary measurements. The use of the model is demonstrated for surfactant Habon-G as an example.

Equilibrium-Turbulent Boundary Layer Prediction for a Proposed Prandtl Mixing Length Distribution

1968 ◽  
Vol 10 (5) ◽  
pp. 426-433 ◽  
Author(s):  
F. C. Lockwood
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Boundary Layers ◽  
Length Distribution ◽  
Momentum Equation ◽  
Turbulent Boundary Layers ◽  
Mixing Length ◽  
Good Agreement

The momentum equation is solved numerically for a suggested ramp variation of the Prandtl mixing length across an equilibrium-turbulent boundary layer. The predictions of several important boundary-layer functions are compared with the equilibrium experimental data. Comparisons are also made with some recent universal recommendations for turbulent boundary layers since the equilibrium experimental data are limited. Good agreement is found between the predictions, the experimental data, and the recommendations.

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