Investigation on the characteristics of turbulence transport for momentum and heat in a drag-reducing surfactant solution flow

2004 ◽  
Vol 16 (9) ◽  
pp. 3281-3295 ◽  
Author(s):  
F.-C. Li ◽  
Y. Kawaguchi ◽  
K. Hishida
Keyword(s):  
Surfactant Solution ◽  
Solution Flow ◽  
Turbulence Transport

Experimental Study of Turbulence Transport in a Dilute Surfactant Solution Flow Investigated by PIV

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Weiguo Gu ◽  
Yasuo Kawaguchi ◽  
Dezhong Wang ◽  
Saito Akihiro
Keyword(s):  
Particle Image ◽  
Reynolds Shear Stress ◽  
Surfactant Solution ◽  
Instantaneous Velocity ◽  
Normal Velocity ◽  
Solution Flow ◽  
Velocity Fluctuations ◽  
Image Velocimetry ◽  
Turbulence Transport ◽  
Main Factor

Drag-reducing flow of dilute surfactant solution in the two-dimensional channel is investigated experimentally by using particle image velocimetry (PIV) system. Five hundred instantaneous velocity frames of u-v in the x-y plane are taken by PIV for every condition. Fluctuation intensity and instantaneous velocity distributions are discussed in order to study the turbulence transport in the drag-reducing flow. As compared with water, the results show that wall-normal velocity fluctuations in the drag-reducing flow are suppressed significantly, and instantaneous velocity distributions display different features. Moreover, the drag-reducing flow exhibits the reduced inclination angle of turbulence transport and appearance of “zero Reynolds shear stress.” High shear dissipation also appears in some solutions. Based on the analysis of the balance of mean and mean turbulent kinetic energies, it is found that the complex rheology, i.e., the elasticity and viscosity of the solution, is considered as the main factor that change the characteristics of turbulence transport.

scholarly journals Study on the Drag Reducing Channel Fluids by Experiments and DNS Using Giesekus Model

2014 ◽  
Vol 6 ◽  
pp. 175059 ◽  
Author(s):  
Weiguo Gu ◽  
Dezhong Wang ◽  
Yasuo Kawaguchi
Keyword(s):  
Shear Stress ◽  
Channel Flow ◽  
Mass Concentration ◽  
Reynolds Shear Stress ◽  
Surfactant Solution ◽  
Solution Flow ◽  
Velocity Fluctuations ◽  
Giesekus Model ◽  
Numerical Studies ◽  
Fluid Characteristics

Both experimental and numerical studies are simultaneously performed for fully developed water and surfactant solution channel flow. The comparison aims at the surfactant solution flow in experiment with mass concentration of 25 ppm at Re = 1000 and Giesekus model with Weissenberg numbers of 10 and 40 at Reτ = 150. Big differences are found between the experimental and DNS results by comparing the distributions of velocity fluctuations, Reynolds shear stress, and so on. Although large drag reduction appears in DNS, Giesekus model has some limitations in describing the fluid characteristics and viscoelasticity of the surfactant solution.

Spectral Analysis and Discussion on the Velocity Fluctuation in Drag Reducing Channel Flow by Surfactant Additives

2016 ◽  
Author(s):  
Yuichi Kaiho ◽  
Shumpei Hara ◽  
Takahiro Tsukahara ◽  
Yasuo Kawaguchi
Keyword(s):  
Channel Flow ◽  
Time Scale ◽  
Velocity Fluctuation ◽  
Surfactant Solution ◽  
Turbulent Velocity ◽  
Laser Doppler Velocimeter ◽  
Wall Region ◽  
Solution Flow ◽  
Velocity Fluctuations ◽  
Turbulent Velocity Fluctuation

It is known as the Toms effect that the wall friction coefficient is reduced by adding a small amount of polymer or surfactant into a water flow. In the drag-reducing flow, it is expected that a time scale of turbulent velocity fluctuation is changed by relaxation time due to viscoelasticity. In the present study, experimental analysis of the turbulent velocity fluctuation was performed with temporal characteristics in surfactant solution flow. The velocity fluctuations were measured by using a two-component laser Doppler velocimeter system on turbulent channel flow. And then, we performed statistical operation on those data and examined the time scale. From spectra analysis, it was found that very low frequency velocity fluctuations existed near the wall region in the surfactant solution flow. It was also revealed that the strong anisotropy occurred not only with the intensity but also with frequency distribution in turbulent velocity fluctuations. Moreover, the turbulence contributes nothing to the Reynolds shear stress and behaves as a wave motion. It was concluded that the turbulent eddies and viscoelasticity were two factors contributing to turbulent generation in the viscoelastic turbulent flow, with each factor having its own time scale.

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