Simultaneous PIV and PLIF Measurement on the Drag Reducing Channel Flow of the Homogeneous Surfactant Solution

2011 ◽  
Author(s):  
Takahiro Watanabe ◽  
Kohei Tanaka ◽  
Masaaki Motozawa ◽  
Yasuo Kawaguchi
Keyword(s):  
Drag Reduction ◽  
Reduction Rate ◽  
Surfactant Solution ◽  
Coherent Motion ◽  
Wall Region ◽  
Frictional Drag ◽  
Piv Measurement ◽  
Planar Laser ◽  
The Relationship ◽  
Plif Measurement

Simultaneous Particle Image Velocimetry (PIV) measurement and Planar Laser Induced Fluorescence (PLIF) measurement at the same position were performed to clarify the relationship between spatial structure and mass transfer in the drag reducing surfactant flow. In the drag reducing flow, mass flux is largely suppressed in the near-wall region with increasing drag reduction rate. To discuss the relationship between coherent motion and drag reduction more detail, weighted probability density function was also calculated. As a result of simultaneous measurement, diffusion of wall-normal direction is largely suppressed and this indicated that turbulent coherent structure changes and sweep and ejection which produce the skin frictional drag are suppressed.

scholarly journals Effects of a new drag reduction agent on natural gas pipeline transportation

2019 ◽  
Vol 11 (10) ◽  
pp. 168781401988192
Author(s):  
Yachao Ma ◽  
Zhiqiang Huang ◽  
Zhanghua Lian ◽  
Weichun Chang ◽  
Huan Tan
Keyword(s):  
Natural Gas ◽  
Drag Reduction ◽  
Gas Flow ◽  
Reduction Rate ◽  
Field Tests ◽  
Wall Region ◽  
Pipeline Transportation ◽  
Frictional Drag ◽  
Inner Surface ◽  
Near Wall

Pipeline transportation is the major way to transport natural gas. How to reduce energy dissipation and retain the gas delivery capacity are the main problems of pipeline transportation. In this article, a new drag reduction agent named CPA is synthesized. An experimental investigation on the roughness-reducing effect of CPA on the inner surface of the pipeline is carried out. The effect of CPA on natural gas flow regime in the near-wall region of the pipeline is researched with Fluent software. Field tests for calculating the drag reduction rate of CPA are performed. The results show that CPA can reduce the roughness of the inner surface effectively, and the maximum roughness-reducing percentage is 38.74%. Meanwhile, CPA can reduce the frictional drag and thereby improve transportation capacity of pipelines. After injecting CPA, the streamline of the natural gas in the near-wall region is more consistent. The velocity fluctuation decreases by 93.2%. The mean turbulence intensity decreases by 53.01%. The pipeline pressure further decreases the roughness of the inner surface of the pipeline. The field test shows that the maximum drag reduction rate of CPA is 25%, and it is suitable for application in gathering and transportation pipelines of high flow velocity and turbulent rough region.

Parametric Study of Viscoelastic Turbulence Within an Obstructed Channel Flow

2011 ◽  
Author(s):  
Tomohiro Kawase ◽  
Takahiro Tsukahara ◽  
Yasuo Kawaguchi
Keyword(s):  
Drag Reduction ◽  
Reduction Rate ◽  
Weissenberg Number ◽  
Viscoelastic Flow ◽  
Viscoelastic Flows ◽  
Streamwise Vortices ◽  
Newtonian Flow ◽  
Frictional Drag ◽  
Parametric Dependence ◽  
Obstructed Channel Flow

The behavior of viscoelastic flow behind a two-dimensional slits was examined using direct numerical simulations (DNS). We performed DNS at five different conditions with changing the Reynolds number and the Weissenberg number, to investigate the parametric dependence of several characters of the viscoelastic flows (e.g., Toms effect and Barus effect) accompanied by the separation and reattachment. In the present conditions, the drag reduction rate was achieved from 15.1% to 19.7%. It was found that the wall-normal viscoelastic stress mainly enhanced the Barus effect in the present geometry and the streamwise viscoelastic force caused an increase of the drag. We found that, at a Weissenberg number higher than a certain level, the drag reduction rate should be decreased despite the reduced turbulent frictional drag. Moreover, we observed that, in the Newtonian flow, the spanwise vortices were dominant in a downstream region of the slits, while the streamwise vortices were dominant there in the case of the viscoelastic flow.

Instantaneous Turbulent Structure Relating to Momentum and Scalar Transport in a Reducing Channel Flow With Surfactant Additives

2017 ◽  
Author(s):  
Takuya Matsumoto ◽  
Shumpei Hara ◽  
Takahiro Tsukahara ◽  
Yasuo Kawaguchi
Keyword(s):  
Reynolds Shear Stress ◽  
Surfactant Solution ◽  
Outer Edge ◽  
Wall Region ◽  
Turbulent Structures ◽  
Solution Flow ◽  
Partial Explanation ◽  
Vortex Model ◽  
Planar Laser ◽  
High Reynolds

Turbulent surfactant solution flows dramatically suppress turbulent scalar and momentum transports with changes to turbulent structures near the wall. In this study, particle image velocimetry and planar laser induced fluorescence concentration measurement method were used simultaneously to analyze turbulent mass transfer experimentally in surfactant channel flows at high Reynolds number. When compared against the instantaneous flow fields of the water case, the results showed a decrease in the magnitude of elementary vortices in the near-wall region. Momentum and scalar transports are caused by the combination of elementary vortices that are irregularly arranged at the outer edge of the shear layer. A conceptual vortex model is proposed for turbulent scalar transfer that provides a partial explanation for the turbulence statistics of a surfactant solution flow, such as the Reynolds shear stress, turbulent mass flux, and mean concentration distribution.

Experimental Study on Drag Reduction Effect With Traveling Wave Control Using PIV Measurement

2019 ◽  
Author(s):  
Ichiro Suzuki ◽  
Takaaki Shimura ◽  
Akihiko Mitsuishi ◽  
Kaoru Iwamoto ◽  
Akira Murata
Keyword(s):  
Drag Reduction ◽  
Piezoelectric Actuator ◽  
Traveling Wave ◽  
Reynolds Shear Stress ◽  
Reduction Rate ◽  
Vibration Source ◽  
Random Component ◽  
Piv Measurement ◽  
Reduction Effect ◽  
Wave Control

Abstract The influence of the traveling wave control on flow fields is evaluated by experiments using a traveling wavy wall in a fully developed turbulent dual channel flow. We develop a traveling wave generator using a rubber sheet and piezoelectric actuator as a vibration source. A single piezoelectric actuator is installed in the upstream position of the channel. Experiments are performed using traveling waves attenuating in the downstream direction. With traveling wave control, effective drag reduction is confirmed when bulk Reynolds number is within the range of 2000 < Reb < 6000. For Reb = 3000, the maximum drag reduction rate of 10% is obtained. In order to evaluate a relationship between the amplitude attenuation of traveling wave and drag reduction effect, particle image velocimetry (PIV) at multiple positions is performed. Increase of drag is observed near the vibration source whereas drag decreased at other positions. Reduction of random component of Reynolds shear stress can be ascribed to the drag reduction.

scholarly journals Synthesis of FDR-SPC Resin and PIV Measurement for Frictional Drag-reduction

2014 ◽  
Vol 12 (1) ◽  
pp. 49-53
Author(s):  
Sungwoo Chung ◽  
Eunyoung Kim ◽  
Ho Hwan Chun ◽  
Hyun Park ◽  
Inwon Lee
Keyword(s):  
Drag Reduction ◽  
Frictional Drag ◽  
Piv Measurement

scholarly journals Global effect of local skin friction drag reduction in spatially developing turbulent boundary layer

2016 ◽  
Vol 805 ◽  
pp. 303-321 ◽  
Author(s):  
A. Stroh ◽  
Y. Hasegawa ◽  
P. Schlatter ◽  
B. Frohnapfel
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Drag Reduction ◽  
Control Region ◽  
Reduction Rate ◽  
Wall Turbulence ◽  
Local Skin ◽  
Control Schemes ◽  
Local Skin Friction ◽  
Friction Drag Reduction

A numerical investigation of two locally applied drag-reducing control schemes is carried out in the configuration of a spatially developing turbulent boundary layer (TBL). One control is designed to damp near-wall turbulence and the other induces constant mass flux in the wall-normal direction. Both control schemes yield similar local drag reduction rates within the control region. However, the flow development downstream of the control significantly differs: persistent drag reduction is found for the uniform blowing case, whereas drag increase is found for the turbulence damping case. In order to account for this difference, the formulation of a global drag reduction rate is suggested. It represents the reduction of the streamwise force exerted by the fluid on a plate of finite length. Furthermore, it is shown that the far-downstream development of the TBL after the control region can be described by a single quantity, namely a streamwise shift of the uncontrolled boundary layer, i.e. a changed virtual origin. Based on this result, a simple model is developed that allows the local drag reduction rate to be related to the global one without the need to conduct expensive simulations or measurements far downstream of the control region.

Drag Reduction of the Flow Past a Circular Cylinder in Surfactant Solution

2001 ◽  
Author(s):  
Satoshi Ogata ◽  
Keizo Watanabe
Keyword(s):  
Circular Cylinder ◽  
Drag Reduction ◽  
Sodium Salicylate ◽  
Tap Water ◽  
Pressure Coefficient ◽  
Surfactant Solution ◽  
Reduction Ratio ◽  
Number Range ◽  
Surfactant Solutions ◽  
Maximum Drag Reduction

Abstract The flow around a circular cylinder in surfactant solution was investigated experimentally by measurement of the pressure and velocity profiles in the Reynolds number range 6000 < Re < 50000. The test surfactant solutions were aqueous solutions of Ethoquad O/12 (Lion Co.) at concentrations of 50, 100 and 200 ppm, and sodium salicylate was added as a counterion. It was clarified that the pressure coefficient of surfactant solutions in the range of 10000 < Re < 50000 at the behind of the separation point was larger than that of tap water, and the separation angle increased with concentration of the surfactant solution. The velocity defect in surfactant solutions behind a circular cylinder was smaller than those in tap water. The drag coefficients of a circular cylinder in surfactant solutions were smaller than those of tap water in the range 10000 < Re < 50000, and no drag reduction occurred at Re = 6000. The drag reduction ratio increased with increasing concentration of surfactant solution. The maximum drag reduction ratio was approximately 35%.

Durability of a Drag Reducing Solution

2008 ◽  
Vol 18 (1) ◽  
pp. 12421-1-12421-5
Author(s):  
V. Mik ◽  
J. Myska ◽  
Z. Chara ◽  
P. Stern
Keyword(s):  
Turbulent Flow ◽  
Drag Reduction ◽  
Turbulence Intensity ◽  
Surfactant Concentration ◽  
Surfactant Solution ◽  
Small Addition ◽  
Rheological Parameters ◽  
Aging Effects ◽  
Flow Disturbance ◽  
Solution Change

AbstractEffectiveness of drag reduction by small addition of a surfactant in the turbulent flow of water depends on the structure and concentration of the additive, temperature of the solution and turbulence intensity, possible flow disturbance by a mechanical obstacle and the content of ions in water, but also on the age of the surfactant solution. We show how important aging effects are in connection with total surfactant concentration, in particular how rheological parameters of the drag reducing solution change with time.

Drag Reduction Study about Bird Feather Herringbone Riblets

2013 ◽  
Vol 461 ◽  
pp. 201-205 ◽  
Author(s):  
Hua Wei Chen ◽  
Fu Gang Rao ◽  
De Yuan Zhang ◽  
Xiao Peng Shang
Keyword(s):  
Drag Reduction ◽  
Structural Parameters ◽  
Reduction Rate ◽  
Reduction Mechanism ◽  
Surface Drag ◽  
Flight Feather ◽  
Hollow Shaft ◽  
Smooth Edge ◽  
Bird Feather ◽  
Wild Goose

Flying bird has gradually formed airworthy structures e.g. streamlined shape and hollow shaft of feather to improve flying performance by millions of years natural selection. As typical property of flight feather, herringbone-type riblets can be observed along the shaft of each feather, which caused by perfect alignment of barbs. Why bird feather have such herringbone-type riblets has not been extensively discussed until now. In this paper, microstructures of secondary feathers are investigated through SEM photo of various birds involving adult pigeons, wild goose and magpie. Their structural parameters of herringbone riblets of secondary flight feather are statistically obtained. Based on quantitative analysis of feathers structure, one novel biomimetic herringbone riblets with narrow smooth edge are proposed to reduce surface drag. In comparison with traditional microgroove riblets and other drag reduction structures, the drag reduction rate of the proposed biomimetic herringbone riblets is experimentally clarified up to 15%, much higher than others. Moreover, the drag reduction mechanism of herringbone riblets are also confirmed and exploited by CFD.

scholarly journals Effectiveness of Predicting The Spatial Distributions of Target Contaminants of a Coking Plant Based On Their Related Pollutants

2021 ◽  
Author(s):  
Pengwei Qiao ◽  
Donglin Lai ◽  
Sucai Yang ◽  
Qianyun Zhao ◽  
Hengqin Wang
Keyword(s):  
Spatial Distribution ◽  
Prediction Accuracy ◽  
Reduction Rate ◽  
Auxiliary Variables ◽  
Relevant Research ◽  
Sample Data ◽  
Coking Plant ◽  
A Site ◽  
Mean Square Errors ◽  
The Relationship

Abstract The prediction accuracy of the spatial distribution of soil pollutants at a site is relatively low. Related pollutants can be used as auxiliary variables to improve the prediction accuracy. However, little relevant research has been conducted on site soil pollution. To analyze the prediction accuracy of target pollutants combined with auxiliary pollutants, Cu, toluene, and phenanthrene were selected as the target pollutants for this study. Based on geostatistical analysis and spatial analysis, the following results were obtained. (1) The reduction rate of the root mean square errors (RMSEs) for Cu, toluene, and phenanthrene with multivariable cokriging were 68.4%, 81.6%, and 81.2%, respectively, which are proportional to the correlation coefficient of the relationship between the auxiliary pollutants and the target pollutants. (2) The predicted results for Cu, phenanthrene, and toluene and their corresponding related pollutants are more accurate than the results obtained not using the related pollutants. (3) In the interpolation process, the RMSEs for Cu, toluene, and phenanthrene with multivariable cokriging basically increase as the neighborhood sample data increases, and then they become stable. (4) When 84, 61, and 34 sample points were removed, the RMSEs for Cu, toluene, and phenanthrene, respectively with multivariable cokriging were close to the RMSEs of the target pollutants based on the total samples. The results are of great significance to improving the prediction accuracy of the spatial distribution of soil pollutants at coking plant sites.

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