Drag Reduction of a Non-Newtonian Fluid by Fluid Injection at the Wall

1968 ◽  
Vol 2 (4) ◽  
pp. 177-180 ◽  
Author(s):  
E. R. THOMPSON ◽  
W. T. SNYDER
Keyword(s):  
Drag Reduction ◽  
Newtonian Fluid ◽  
Fluid Injection

Drag reduction of a nonnewtonian fluid by fluid injection on a moving wall

1999 ◽  
Vol 69 (3) ◽  
pp. 215-225 ◽  
Author(s):  
M. Akçay ◽  
M. Adil Yükselen
Keyword(s):  
Drag Reduction ◽  
Fluid Injection ◽  
Moving Wall

Effect of Viscoelasticity on the Turbulence Kinetic Energy Budget of the Non-Newtonian Fluid Turbulent Flow Accompanied by Drag Reduction

2007 ◽  
Author(s):  
Y. Kagawa ◽  
B. Yu ◽  
Y. Kawaguchi
Keyword(s):  
Kinetic Energy ◽  
Turbulent Flow ◽  
Drag Reduction ◽  
Turbulent Kinetic Energy ◽  
Newtonian Fluid ◽  
Viscoelastic Fluid ◽  
Energy Budget ◽  
Rheological Parameters ◽  
Fluid Turbulence ◽  
Kinetic Energy Budget

For the purpose of elucidating the mechanism of drag reduction by additives and finding a way to judge optimum drag-reducing additives through a simple rheological test, we performed DNS analysis of viscoelastic fluid turbulent flow in a two-dimensional channel. In this calculation, we employed the Giesekus constitutive equation to model the interaction between water-soluble polymer, or the elastic micellar network structure, and solvent. We calculated the fluid flow by varying the rheological parameters of the model. We examined the turbulent kinetic energy budget and studied the “viscoelastic contribution” term in the budget equation for turbulent intensity, which is not apparent in normal Newtonian fluid turbulence. Viscoelastic contribution has a characteristic effect on viscoelastic fluid turbulence. We concluded that the viscoelastic contribution plays a major role in turbulent frictional drag reduction. Dissipation and viscoelastic contribution serve as a key factor of turbulent kinetic energy loss in most areas of the channel. From the visualization of local and instantaneous eddy behavior, we discussed the relationship between viscoelastic contribution, elastic energy and turbulent production. We found that viscoelastic contribution serves as a direct local source of turbulent production, and that energy is stored in the elasticity.

Experimental Study on the Drag-Reducing Characteristics in Two-Oscillating Grid Turbulence With Polymer Additives

2016 ◽  
Author(s):  
Yue Wang ◽  
Weihua Cai ◽  
Tong-zhou Wei ◽  
Feng-chen Li ◽  
Li-ming Yao ◽  
...  
Keyword(s):  
Experimental Study ◽  
Kinetic Energy ◽  
Drag Reduction ◽  
Polymer Solution ◽  
Turbulent Kinetic Energy ◽  
Newtonian Fluid ◽  
Reduction Rate ◽  
Grid Turbulence ◽  
Solution Flow ◽  
Oscillating Grid

In this paper, we carried out the experimental study to investigate the polymer effect on two-oscillating grid turbulence based on Particle Image Velocimetry. We chose five different concentrations (25, 50, 100, 150 and 200ppm) of polymer solution flow and the Newtonian fluid flow for comparison at three different grid oscillating frequencies (5, 7.5 and 10Hz). The results showed that comparison with the Newtonian fluid case, the turbulent kinetic energy is much smaller in polymer solution cases. A natural definition for drag reduction rate was proposed based on turbulent kinetic energy. It showed that the maximum drag reduction reaches around 80% and the drag-reducing effect increases as the concentration increases. Finally, proper orthogonal decomposition (POD) was used to extract coherent structures in grid turbulence.

scholarly journals Turbulent drag reduction with polymer additive in rough pipes

2009 ◽  
Vol 642 ◽  
pp. 279-294 ◽  
Author(s):  
SHU-QING YANG ◽  
G. DOU
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Drag Reduction ◽  
Turbulent Flows ◽  
Newtonian Fluid ◽  
Effective Viscosity ◽  
Eddy Diffusivity ◽  
Viscous Sublayer ◽  
Friction Factors ◽  
Theoretical Predictions

Friction factor of drag-reducing flow with presence of polymers in a rough pipe has been investigated based on the eddy diffusivity model, which shows that the ratio of effective viscosity caused by polymers to kinematic viscosity of fluid should be proportional to the Reynolds number, i.e. u∗R/ν and the proportionality factor depends on polymer's type and concentration. A formula of flow resistance covering all regions from laminar, transitional and fully turbulent flows has been derived, and it is valid in hydraulically smooth, transitional and fully rough regimes. This new formula has been tested against Nikuradse and Virk's experimental data in both Newtonian and non-Newtonian fluid flows. The agreement between the measured and predicted friction factors is satisfactory, indicating that the addition of polymer into Newtonian fluid flow leads to the non-zero effective viscosity and it also thickens the viscous sublayer, subsequently the drag is reduced. The investigation shows that the effect of polymer also changes the velocity at the top of roughness elements. Both experimental data and theoretical predictions indicate that, if same polymer solution is used, the drag reduction (DR) in roughened pipes becomes smaller relative to smooth pipe flows at the same Reynolds number.

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