Vortex Motion in a Swirling Flow of Surfactant Solution with Drag Reduction

2005 ◽  
Vol 128 (1) ◽  
pp. 101-106 ◽  
Author(s):  
Mizue Munekata ◽  
Kazuyoshi Matsuzaki ◽  
Hideki Ohba
Keyword(s):  
Drag Reduction ◽  
Pipe Flow ◽  
Swirling Flow ◽  
Vortex Motion ◽  
Flow Characteristics ◽  
Surfactant Solution ◽  
Industrial Applications ◽  
Laser Doppler Velocimeter ◽  
Straight Pipe ◽  
Forced Vortex

Surfactants are well known as additives which induce drag reduction in the straight (nonswirling) pipe flow. However, in industrial applications of the drag-reducing effect, many flow fields besides the straight pipe flow need to be considered. The purpose of this study is to investigate the flow characteristics of the surfactant solution in swirling pipe flow. The drag-reducing effect is estimated from the measurement of wall pressure drop and velocity profiles on various pipe sections by two-dimensional LDV (Laser Doppler Velocimeter). Since the surfactant solution has viscoelasticity, interesting flow characteristics are obtained. The decay of swirl, the vortex type and the turbulence intensity are discussed, compared with the swirling flow of the water. As the results, it is concluded that the change from Rankin’s combined vortex to the forced vortex at a more upstream section by suppressing progress of free vortex and stretch of forced vortex introduces considerable drag reduction. Oscillation of the vortex core is also investigated, and it is found that the oscillation is independent of swirl number.

Vortex Motion in a Swirling Flow of Surfactant Solution With Drag Reduction in a Pipe

2003 ◽  
Author(s):  
Mizue Munekata ◽  
Kazuyoshi Matsuzaki ◽  
Hideki Ohba
Keyword(s):  
Drag Reduction ◽  
Turbulence Intensity ◽  
Pipe Flow ◽  
Vortex Core ◽  
Swirling Flow ◽  
Vortex Motion ◽  
Flow Characteristics ◽  
Surfactant Solution ◽  
Industrial Applications ◽  
Straight Pipe

A surfactant is well known as an additive that brings about drag-reduction in straight (non-swirling) pipe flow. However in industrial applications of the drag-reducing effect, many flow fields exist including the straight pipe flow. The purpose of this study is to investigate the flow characteristics of surfactant solution swirling pipe flow. The drag reducing effect is estimated from the measurement wall pressure loss and the velocity profiles on various pipe sections are measured by 2 dimensional LDV. Since the surfactant solution has viscoelasticity, interesting flow characteristics are shown. The decay of swirl, the vortex type and the turbulence intensity are discussed, compared with the water swirling flow. The oscillating of vortex core is also investigated.

1315 Drag reduction in circuit pipe flow of non-ionic surfactant solution

2010 ◽  
Vol 2010 (0) ◽  
pp. 383-384
Author(s):  
Kotaro MIYAGAWA ◽  
Shinji TAMANO ◽  
Yohei MORINISHI
Keyword(s):  
Drag Reduction ◽  
Pipe Flow ◽  
Surfactant Solution ◽  
Ionic Surfactant

2323 A Study on Relationship between Swirling Flow Characteristics and Rheologic Characteristics of Surfactant Solution

2006 ◽  
Vol 2006.2 (0) ◽  
pp. 59-60
Author(s):  
Kenichiro MATSUO ◽  
Hiroki TAWARA ◽  
Mizue MUNEKATA ◽  
Hiroyuki YOSHIKAWA ◽  
Hideki OHBA
Keyword(s):  
Swirling Flow ◽  
Flow Characteristics ◽  
Surfactant Solution

Experimental study of turbulent swirling flow in a straight pipe

1991 ◽  
Vol 225 ◽  
pp. 445-479 ◽  
Author(s):  
Osami Kitoh
Keyword(s):  
Swirling Flow ◽  
Direct Method ◽  
Vortex Motion ◽  
Tangential Velocity ◽  
Wall Friction ◽  
Shear Stresses ◽  
Wall Region ◽  
The Core ◽  
Swirl Intensity ◽  
Forced Vortex

Swirling flow through a pipe is a highly complex turbulent flow and is still challenging to predict. An experimental investigation is performed to obtain systematic data about the flow and to understand its physics. A free-vortex-type swirling flow is introduced in a long straight circular pipe. The swirling component decays downstream as a result of wall friction. The velocity distributions are continuously changing as they approach fully developed parallel flow. The swirl intensity Ω, defined as a non-dimensional angular momentum flux, decays exponentially. The decay coefficients, however, are not constant as conventionally assumed, but depend on the swirl intensity. The wall shear stresses are measured by a direct method and, except in a short inlet region, are a function only of the swirl intensity and the Reynolds number. The velocity distributions and all Reynolds stress components are measured at various axial positions in the pipe. The structure of the tangential velocity profile is classified into three regions: core, annular and wall regions. The core region is characterized by a forced vortex motion and the flow is dependent upon the upstream conditions. In the annular region, the skewness of the velocity vector is noticeable and highly anisotropic so that the turbulent viscosity model does not work well here. The tangential velocity is expressed as a sum of free and forced vortex motion. In the wall region the skewness of the flow becomes weak, and the wall law modified by the Monin–Oboukhov formula is applicable. Data on the microscale and the spectrum are also presented and show quite different turbulence structures in the core and the outer regions.

Swirling Flow of a Viscoelastic Fluid With Free Surface—Part I: Experimental Analysis of Vortex Motion by PIV

2005 ◽  
Vol 128 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Jinjia Wei ◽  
Fengchen Li ◽  
Bo Yu ◽  
Yasuo Kawaguchi
Keyword(s):  
Free Surface ◽  
Vortex Breakdown ◽  
Swirling Flow ◽  
Vortex Motion ◽  
Surfactant Solution ◽  
Particle Image Velocimetry System ◽  
Meridional Plane ◽  
Cylindrical Wall ◽  
Rotating Disc ◽  
Solution Flow

The swirling flows of water and CTAC (cetyltrimethyl ammonium chloride) surfactant solutions (50-1000ppm) in an open cylindrical container with a rotating disc at the bottom were experimentally investigated by use of a double-pulsed PIV (particle image velocimetry) system. The flow pattern in the meridional plane for water at the present high Reynolds number of 4.3×104 differed greatly from that at low Reynolds numbers, and an inertia-driven vortex was pushed to the corner between the free surface and the cylindrical wall by a counter-rotating vortex caused by vortex breakdown. For the 1000ppm surfactant solution flow, the inertia-driven vortex located at the corner between the bottom and the cylindrical wall whereas an elasticity-driven reverse vortex governed the majority of the flow field. The rotation of the fluid caused a deformation of the free surface with a dip at the center. The dip was largest for the water case and decreased with increasing surfactant concentration. The value of the dip was related to determining the solution viscoelasticity for the onset of drag reduction.

scholarly journals Verification of Baffle Factor for Straight Pipe Flow

2018 ◽  
Vol 65 (1) ◽  
pp. 31-39
Author(s):  
Wojciech Artichowicz ◽  
Aneta Łuczkiewicz ◽  
Jerzy M. Sawicki
Keyword(s):  
Pipe Flow ◽  
Flow Model ◽  
Flow System ◽  
Accurate Determination ◽  
Plug Flow ◽  
Flow Characteristics ◽  
Complex Problem ◽  
Straight Pipe ◽  
Advection Diffusion Equation ◽  
Dynamics Simulations

AbstractThe baffle factor is a parameter widely used to describe flow system characteristics. This indicator is very important in designing disinfection devices. For example, it is used to convert the plug flow time to the actual fluid residence time in the flow system of interest. Its accurate determination is a complex problem requiring tracer experiments or computational fluid dynamics simulations. Therefore, in practice, it is often taken from tables provided in the literature. The literature sources, however, state that the baffle factor for a flow in a straight pipe is equal to unity, which implies the identity between the pipe flow model and the plug flow model. This assumption is doubtful. The aim of the present work is to verify the baffle factor values assumed for the pipe flow. The merit of this study is the analytical derivation of the expression describing the baffle factor value with respect to flow characteristics. To this purpose, the analytical solution of a one-dimensional advection-diffusion equation with a Heaviside initial condition was used. It was demonstrated that the aforementioned assumption is wrong, as the baffle factor for a straight pipe is significantly less than unity.

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