Effects of periodic flow fluctuations on magnetic resonance flow images

Date

2004-08-01

Author

Uludağ, Yusuf
McCarthy, MJ

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

162
views

0
downloads

The effects of periodic velocity fluctuations on magnetic resonance flow images are investigated experimentally and theoretically. In the experiments, laminar pipe flow of water was examined. The flow was driven by a constant pressure head with a superimposed sinusoidal component with the frequency m, varied from 0 to 1 Hz, whereas in the simulations omega(z) was between 0 to 65 Hz. The velocity profiles obtained from the experimental results compare well with the theoretical calculations. Both theory and experiment show that flow fluctuations produce artifacts in the form of "ghosts" of the primary image, which are spaced at equal intervals in the phase encoding (flow) direction. The distance between ghosts depends on the fluctuation frequency and on the experimentally specified parameters (phase encoding gradient step, repetition time, phase encoding duration, and time difference between phase encoding gradient lobes). The amplitudes of the ghosts depend on amplitude of the flow fluctuation and diminish at frequencies higher than 30 Hz. (C) 2004 American Institute of Chemical Engineers.

Subject Keywords

Biotechnology, Environmental Engineering, General Chemical Engineering

URI

https://hdl.handle.net/11511/47658

Journal

AICHE JOURNAL

DOI

https://doi.org/10.1002/aic.10152

Collections

Department of Chemical Engineering, Article

Suggestions

OpenMETU
Core

Effect of thermal neutron irradiation on the elastic constants of tourmaline Özkan, H. (Informa UK Limited, 1987-2) The effect of thermal neutron irradiation due to the B10(n, α)Li7 reaction on the elastic wave velocities and the elastic moduli of tourmaline crystals has been studied. Oriented tourmaline samples have been irradiated with thermal neutrons to 7.6 × 1018n/cm2 and the elastic wave velocities determined by ultrasonic measurements. The elastic wave velocities are not affected by thermal neutron irradiation below 8 × 10l7n/cm2, effects starting to appear at approximately 1 × l018n/cm2 with more important decrea...
Experimental investagation of drag reduction effects of polymer additives on turbulent pipe flow Zeybek, Şerife; Uludağ, Yusuf; Department of Chemical Engineering (2005) Since the discovery of the drag reduction effects of even small amount of macromolecules in solutions in turbulent pipe flows, there have been many experimental and theoretical studies in order to understand mechanisms behind this phenomenon. Theories have been proposed based on the observations on the change in the characteristics of the turbulent flow near the pipe wall where friction of the momentum transfer between the flow and the conduit takes place. In this study drag reduction in fully developed tur...
Detecting stability of conical spouted beds based on information entropy theory Savari, Chiya; Sotudeh-Gharebagh, Rahmat; Külah, Görkem; KÖKSAL, MURAT; Mostoufi, Navid (Elsevier BV, 2019-02-01) Effects of particle size, particle density, gas inlet diameter and static bed height on the stability of operation in conical spouted beds were investigated through analyses of information entropy of pressure fluctuations. In this respect, the maximum information entropy of pressure fluctuations was used as a stability criterion. The results showed that stability of the bed increases with an increase in the maximum entropy. The maximum information entropy of pressure fluctuations increases with increasing p...
FINITE VOLUME SIMULATION OF 2-D STEADY SQUARE LID DRIVEN CAVITY FLOW AT HIGH REYNOLDS NUMBERS YAPICI, KERİM; Uludağ, Yusuf (FapUNIFESP (SciELO), 2013-10-01) In this work, computer simulation results of steady incompressible flow in a 2-D square lid-driven cavity up to Reynolds number (Re) 65000 are presented and compared with those of earlier studies. The governing flow equations are solved by using the finite volume approach. Quadratic upstream interpolation for convective kinematics (QUICK) is used for the approximation of the convective terms in the flow equations. In the implementation of QUICK, the deferred correction technique is adopted. A non-uniform st...
MOTION OF A CIRCULATING POWER-LAW DROP TRANSLATING THROUGH NEWTONIAN FLUIDS AT INTERMEDIATE REYNOLDS NUMBERS Gürkan, Türker (Informa UK Limited, 1989-6) The equations of motion for the flow of a power-law fluid sphere in a Newtonian continuous phase have been approximately satisfied by Galerkin's method: External and internal stream functions have been obtained for the following ranges of variables: 10-50 for Re0, 0.1-1000 for the viscosity ratio parameters, X, and 0.6-1.0 for the dispersed phase power-law index, ni,. It is predicted that pseudoplasticity in the dispersed phase causes a reduction in the circulation within the drop and that it has a minor ef...

Citation Formats

Y. Uludağ and M. McCarthy, “Effects of periodic flow fluctuations on magnetic resonance flow images,” AICHE JOURNAL, pp. 1662–1671, 2004, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/47658.