Effect Of Flow Profile Research Articles

Flow structure around a microswimmer at fluid–fluid interface

Living organisms such as bacteria and algae often form biofilms at air–liquid and/or liquid–liquid interfaces. Therefore, it is important to understand the hydrodynamic interaction between the fluid–fluid interface and microorganisms. In the present study, a squirmer model is employed to study the flow field structures around a symmetrically trapped spherical microswimmer at an interface separating two fluids with viscosity contrast. In these simulations, Reynolds ( Re ) and Capillary ( Ca ) numbers are very small, and hence the contribution of inertia and interface deformations are neglected. The squirmer model is validated against the analytical solution obtained by considering a source dipole. It is observed that the flow structure and vorticity distribution around the microswimmers are strongly influenced by the squirmer parameter (β) and viscosity contrast (λ). Furthermore, the interplay between force-dipole and source-dipole along with viscosity contrast leads to a range of flow structures such as symmetric four-lobe and asymmetric quadrupolar flow fields. This flow structure asymmetry around the swimmer is quantified with different steady state orientations (φ). The effect of flow profile on the passive tracer particle transport is explored in terms of trajectories. Specifically, larger values of φ result in more profound curly trajectories.

Cross‐stream migration of nonspherical particles in second‐order fluid flows: Effect of flow profiles

AbstractWe investigate the cross‐stream migration of spheroidal particles in a weakly viscoelastic fluid under various unbound parabolic flows (circular and elliptic tube flow, as well as 2D slit flow). The viscoelastic fluid investigated is a second‐order fluid under the co‐rotational limit. Our theory finds that the different flow profiles do not significantly alter the migration speed of particles toward the flow centerline, but drastically alter their orientation dynamics. At long times, prolate particles align along the flow direction in a circular tube flow, but undergo log‐rolling in a 2D slit flow. We explain the origin of these orientation dynamics, and explain why such behavior can give rise to a similar cross‐stream migration velocity. We lastly examine particle motion in an unbound elliptic tube flow with unequal velocity curvature in the two lateral directions. We quantify the conditions under which the long‐time particle orientation changes from log‐rolling to flow‐alignment.

Effect of flow profiles on the flow subjected to oscillation forcing: An example of droplet mobilization in constricted tubes

Poiseuille flow was widely assumed in the analysis of fluid flow in porous media due to its simple form. It can describe the flow behavior at creeping flow conditions very well. However, errors were reported in the literature by the use of this parabolic velocity profile in some dynamic circumstances. The effect of velocity profiles on the capillary flow was discussed in this study when oscillation forcing was applied to the flow. An example of the response of nonwetting droplets to the oscillation forcing in a constricted capillary was analyzed: the velocity profiles of Poiseuille flow, starting flow and oscillatory flow were used in this analysis for a comparison. The easiness of implementing these velocity profiles in the theoretical analysis is in this order: Poiseuille flow, starting flow, and oscillatory flow, but the accuracy is in the order: oscillatory flow, starting flow, and Poiseuille flow. By using theoretical approach, we quantified the dimensionless numbers at which the velocity profile of Poiseuille flow profile can be used to approximate the velocity profiles of starting flow or oscillatory flow. The sensitivity of the viscosity ratio was also discussed in this study. When certain conditions of the dimensionless numbers are met, the use of the velocity profile of Poiseuille flow can be justified even though the flow is in a dynamic condition. Otherwise, the approximation by using Poiseuille flow could cause significant errors when the flow is subjected to oscillation forcing.

Axisymmetric Wave Propagation in Uniform Gas Flow Confined by Rigid-Walled Pipeline

This paper deals with the axisymmetric acoustic wave propagating along the perfect gas in the presence of a uniform flow confined by a rigid-walled pipeline. Under the linear acoustic assumption, mathematical formulation of wave propagation is deduced from the conservations of mass, momentum and energy. Meanwhile a method based on the Fourier–Bessel theory is introduced to solve the problem. Comprehensive comparisons of the phase velocity and wave attenuation between the non-isentropic and isentropic acoustic waves are provided. Meanwhile the effects of flow profile, acoustic frequency, and pipeline radius are analyzed.

Isentropic acoustic propagation in a viscous fluid with uniform circular pipeline flow

Isentropic wave propagation in a viscous fluid with a uniform mean flow confined by a rigid-walled circular pipeline is considered. A method based on the Fourier-Bessel theory, which is complete and orthogonal in Lebesgue space, is introduced to solve the convected acoustic equations. After validating the method's convergence, the cut-off frequency of wave modes is addressed. Furthermore, the effect of flow profile on wave attenuation is analyzed. Meanwhile, measurement performance of an ultrasonic flow meter based on wave propagation is numerically accounted.

Effect of flow profile on wind energy efficiency

We study here the effect of flow profile on the density and temperature gradient perturbations in a plasma fluid medium. The result shows that the flow profile has an extensive role to play in the general stability of the perturbations. For some type of profiles, the perturbations tend to get stabilised, whereas for other type of profiles these are excited. This result might have a crucial role to play in designing the turbines in a wind energy generator, and with a proper choice of flow profiles, the efficiency of the energy generation could be enhanced to a substantial extent.

Response to “Comment on ‘Effect of flow profile on low frequency drift-type waves in a dusty plasma’ ” [Phys. Plasmas 9, 1481 (2002)

The objections of Vranejes et al. are unfounded and are shown to be based on the complete misunderstanding of our manuscript by the authors.

Comment on “Effect of flow profile on low frequency drift-type waves in a dusty plasma” [Phys. Plasmas 8, 3150 (2001)

It is pointed out that a recently published study [Phys. Plasmas 8, 3150 (2001)] of the effects of magnetic shear and shear flow on dust-drift waves has already been studied earlier. Further, the results obtained in Phys. Plasmas 8, 3150 (2001) are erroneous as the shear flow effect has been included in an inappropriate manner.

A three-dimensional finite element model for the control of certain non-linear bioreactors

This paper deals with the dynamics of non-linear distributed parameter fixed-bed bioreactors. The model consists of a pair of non-linear partial differential (evolution) equations. The true spatially three-dimensional situation is considered instead of the usual one-dimensional approximation. This enables one to take into account the effects of flow profiles and the true location of the measurement transducer. The (output) evolution of the corresponding open-loop control system is simulated. Furthermore, the associated closed-loop system with respect to the relevant output function is considered. Especially, the asymptotic output tracking is found to be successful by applying the usual process based on the state feedback linearization.

Tubular reactors: Effect of flow profile on conversion for a nonelementary reaction

Tubular reactors: Effect of flow profile on conversion for a nonelementary reaction

A Pressure Index for Predicting the Effect of Flow Profiles on Orifice Meter Performance

The influence of upstream non-normal velocity distributions on orifice meters is studied experimentally. Several parameters, based on the velocity distribution, were found to correlate with the discharge coefficient. A pressure index, based on wall-pressure measurements, was also shown to correlate with the discharge coefficient. An examination of a proposed prediction method using the pressure index, showed that it appears possible to predict the performance of orifice meters when the approach profiles are non-normal.

Effects of flow profile on electromagnetic flowmeter accuracy

SPECIAL COMMUNICATIONSEffects of flow profile on electromagnetic flowmeter accuracySamuel C. Goldman, Nathan B. Marple, and William L. ScolnikSamuel C. Goldman, Nathan B. Marple, and William L. ScolnikPublished Online:01 May 1963https://doi.org/10.1152/jappl.1963.18.3.652MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByElectromagnetic Blood Flow Measurements15 January 2010The measurement of liver blood flow: a review of experimental and clinical methodsJournal of Surgical Research, Vol. 112, No. 1Simultaneous assessment of cardiac output with pulsed Doppler and electromagnetic flowmeters during cardiac stimulationJournal of Pharmacological and Toxicological Methods, Vol. 30, No. 1Experimental validation of Doppler echocardiographic measurement of volume flow through the stenotic aortic valve.Circulation, Vol. 78, No. 2Measurement of hepatic blood flowJournal of Surgical Research, Vol. 39, No. 5Quantitative assessment of low blood flow using an electromagnetic flowmeterJournal of Surgical Research, Vol. 31, No. 3The electromagnetic flowmeterEvaluation of the microsphere-method for determination of cardiac output8 July 2009 | Scandinavian Journal of Clinical and Laboratory Investigation, Vol. 39, No. 5The hydraulic impedance of the lower limb: Its relevance to the success of bypass operations for occlusion of the superficial femoral arteryBritish Journal of Surgery, Vol. 63, No. 5The Design of Electromagnetic Flowmeter Probes with Homogeneous Luminal Magnetic FieldsIEEE Transactions on Biomedical Engineering, Vol. BME-23, No. 1Sequential Velocity Development in the Ascending and Descending Aorta of the DogCirculation Research, Vol. 31, No. 3Measurement of Pulsatile Flow and Flow VelocityVelocity Profiles in the Main Pulmonary Artery of Dogs and Man, Measured with a Thin-Film Resistance AnemometerCirculation Research, Vol. 27, No. 6An electromagnetic flowmeter for studying changes of cardiac output in unanaesthetized ratsMedical & Biological Engineering, Vol. 7, No. 5A transistorized squarewave electromagnetic flowmeter—IIMedical & Biological Engineering, Vol. 7, No. 2The electromagnetic blood flowmeter15 May 2002 | Journal of Physics E: Scientific Instruments, Vol. 1, No. 12Some Applications and Limitations of Electromagnetic Blood Flow Measurements in Chronic Animal PreparationsGastroenterology, Vol. 52, No. 2Methods for measurenment of blood flowJournal of Surgical Research, Vol. 6, No. 8Baseline errors in cuff electromagnetic flowmetersMedical & Biological Engineering, Vol. 4, No. 1Magnetic Field Measurement for Electromagnetic Flowmeters5 August 2002 | Physics in Medicine and Biology, Vol. 11, No. 1 More from this issue > Volume 18Issue 3May 1963Pages 652-657 Copyright & PermissionsCopyright © 1963 the American Physiological Societyhttps://doi.org/10.1152/jappl.1963.18.3.652PubMed31099544History Published online 1 May 1963 Published in print 1 May 1963 Metrics