FEM solutions of magnetohydrodynamic and biomagnetic fluid flows in channels

Download
2014
Türk, Önder
In this thesis, solutions to steady and unsteady flow problems of incompressible viscous fluids are obtained numerically. In computational aspects, the primary focus is on the finite element analysis, however, spectral collocation and boundary element methods are also employed. The two-dimensional Navier-Stokes (N-S) equations in stream function-vorticity form are solved by using both finite element method (FEM) and Chebyshev spectral collocation method (CSCM). The accuracy of the FEM and CSCM methodologies is investigated by solving some benchmark fluid flow problems such as lid-driven cavity flow, and natural convection flow in enclosures. The natural convection flow problem is also considered under the effect of an externally applied magnetic field. The magnetohydrodynamic (MHD) system is coupled with the temperature effects through the gravitational force by means of the Boussinesq approximation. Different flow configurations with various boundary conditions are examined on both inclined and non-inclined enclosures, and the solutions are obtained by using FEM and CSCM for the case of small magnetic Reynolds number. The problem of unsteady, one-dimensional MHD flow and heat transfer between parallel plates, is solved with CSCM due to its simplicity in computations. For the time discretization, an implicit backward finite difference scheme is presented. The effect of the movement of the upper plate on the flow, and the convection action in terms of inflow/outflow through plates are examined. The MHD flow between parallel plates is extended to the case of dusty fluid by including differential equations for the dust particles. The Navier-slip conditions for both the fluid and dust particle velocities are introduced. The Hartmann number, viscosity parameter, and Navier-slip parameter influences on the flow and temperature are visualized in terms of graphics together with discussions. The biomagnetic fluid flow (blood flow) and heat transfer in channels between plates with various physical configurations are simulated. A blood model consistent with biomagnetic fluid dynamics (BFD), which includes the principles of MHD and ferrohydrodynamics (FHD), is considered. The fluid is assumed to be Newtonian, and both electrically conducting and nonconducting fluid flows are separately considered. The FEM and DRBEM applications are introduced for the steady biomagnetic fluid flow model where the fluid is considered as electrically non-conducting. The effects of the externally applied magnetic field on the flow and heat distribution are analyzed in details. FEM applications are also presented for the solution of biomagnetic fluid flow through channels between plates with differing constriction profiles. Alterations in the behaviors of the flow and temperature of the biomagnetic fluid due to the stenoses in the channel and location and intensity of the magnetic source are analyzed.

Suggestions

Radial basis function and dual reciprocity boundary element solutions of fluid dynamics problems
Gürbüz, Merve; Tezer Sezgin, Münevver; Department of Mathematics (2017)
In this thesis, the two-dimensional, laminar steady or unsteady flow of a viscous, incompressible, electrically conducting fluid is considered in channels of several geometries under the impact of a uniform magnetic field with different orientations. Magnetohydrodynamic (MHD) flow governed by the hydrodynamic and electromagnetic equations is solved numerically with or without Stokes approximation and with or without magnetic induction due to the large or small values of Reynolds and magnetic Reynolds number...
Dielectric Properties of Ethanol and Gasoline Mixtures by Terahertz Spectroscopy and an Effective Method for Determination of Ethanol Content of Gasoline
ARIK, Enis; Altan, Hakan; Esentürk, Okan (American Chemical Society (ACS), 2014-05-01)
Investigation of frequency dependent permittivity of mixture solutions provides information on the role of intermolecular interactions on relaxation processes of solvent and solute molecules. In this study the dielectric properties of ethanol/gasoline mixtures in the terahertz spectral region are investigated. Frequency dependent absorption coefficients, refractive indices, and complex permittivities of pure ethanol and gasoline, and their mixtures at varying ethanol volume percentages (v/v %) are reported....
Optimal control in fluid flow problems with POD applications to FEM solutions
Evcin, Cansu; Uğur, Ömür; Department of Scientific Computing (2018)
This study investigates the numerical solutions of optimal control problems constrained by the partial differential equations (PDEs) of laminar fluid flows and heat transfer with the model order reduction (MOR). This is achieved by the three objectives of the thesis: obtaining accurate solutions, controlling the dynamics of the fluid and reducing the computational cost. Fluids exposed to an external magnetic field and the heat transfer are governed by the magnetohydrodynamics (MHD) and energy equations. Con...
Adsorption of Cd(II) ions from aqueous solutions using activated carbon prepared from olive stone by ZnCl2 activation
Kula, Ibrahim; Ugurlu, Mehmet; Karaoglu, M. Hamdi; Celik, Ali (2008-02-01)
This study is aimed to remove Cd(II) ions from aqueous solutions by adsorption. As adsorbent, activated carbon prepared from olive stone, an agricultural solid by-product was used. Different activating agent (ZnCl2) amounts and adsorbent particle size were studied to optimize adsorbent surface area. The adsorption experiments were conducted at different parameters such as, adsorbent dose, temperature, equilibrium time and pH. According to the experiments results, the equilibrium time, optimum pH, adsorbent ...
Spectroelectrochemical investigation of the anodic oxidation of dibenzo-18-crown-6
Cihaner, A; Önal, Ahmet Muhtar (Elsevier BV, 2004-10-01)
Poly(dibenzo-18-crown-6) (poly-DB18C6) was synthesized by electrochemical oxidation of dibenzo-18-crown-6 (DB18C6) using a mixture of acetonitrile and dichloromethane as the solvent and tetrabutylammonium tetrafluoroborate (TBABF(4)) or tetrabutylammonium hexafluorophosphate (TBAPF(6)) as supporting electrolyte. The anodic polymerization of DB18C6 was investigated using in situ ESR and in situ UV-Vis spectroscopic techniques. Spectroelectrochemical (SPEL), properties and thermal analysis of the resulting po...
Citation Formats
Ö. Türk, “FEM solutions of magnetohydrodynamic and biomagnetic fluid flows in channels,” Ph.D. - Doctoral Program, Middle East Technical University, 2014.