Large Modulation Effects on Photorefractive Grating Formations with Moving Gratings

1992 ◽  
Vol 261 ◽  
Author(s):  
George A. Brost
Keyword(s):  
Finite Difference ◽  
Numerical Solutions ◽  
Finite Difference Technique ◽  
Analytical Expressions ◽  
Photorefractive Grating

ABSTRACTA finite difference technique was used to model photorefractive grating formations under conditions of moving gratings and large modulation. These results were generalized through analytical expressions which approximate the numerical solutions.

Model Berangka Untuk Perlakuan Muka Air Tanah Dari Pengaruh Imbuhan Fana

1983 ◽  
pp. 41-55
Author(s):  
Wan Mokthar Nawang ◽  
Md. Zaid Ali
Keyword(s):  
Finite Difference ◽  
Groundwater Recharge ◽  
Numerical Solutions ◽  
Experimental Results ◽  
Piecewise Constant ◽  
Finite Difference Technique ◽  
Unconfined Aquifers ◽  
Implicit Finite Difference

Masalah imbuhfana ke atas muka air tanah dari akuifer bebas berhad adalah diselesaikan menggunakan kaedah berangka beza berhad implisit. Keputusan penyelesaian berangka disahkan baik berbanding dengan kaedah analitik dan ujikaji makmal. Seterusnya kelakuan muka air tanah diselidiki mengenakan imbuh-imbuh jenis sekata,imbuh sekata berubah dengan masa dan imbuh berkurang secara lelurus dengan masa. The problem of transient groundwater recharge from strip basins to finite unconfined aquifers is solved numerically by implicit finite difference technique. The numerical solutions are verified by comparison with analytical and experimental results. The behaviour of watertable is further examined by applying set of different recharge i.e. constant, piecewise constant, and decreasing linearly with time recharge.

Induction Electrohydrodynamic Pump in a Vertical Configuration: Part 1—Theory

1989 ◽  
Vol 111 (3) ◽  
pp. 664-669 ◽  
Author(s):  
J. Seyed-Yagoobi ◽  
J. C. Chato ◽  
J. M. Crowley ◽  
P. T. Krein
Keyword(s):  
Finite Difference ◽  
Temperature Profile ◽  
Electric Conductivity ◽  
Secondary Flow ◽  
Joule Heating ◽  
Numerical Solutions ◽  
Controlling Factors ◽  
Heated Wall ◽  
Optimum Frequency ◽  
Finite Difference Technique

An induction electrohydrodynamic (EHD) pump in an axisymmetric, vertical configuration is studied theoretically. The model includes the effect of entrance conditions, buoyancy effects, secondary flow, and Joule heating. Primarily the forward (cooled wall) and to a lesser extent the backward (heated wall) modes are investigated. A finite difference technique is used to obtain the numerical solutions. A set of these solutions is presented to show the influence of the controlling factors of operating an induction EHD pump. The results indicate that the entrance temperature profile plays an important role in the operation of the pump because steeper profiles produce higher velocities. The pump must be operated at an optimum frequency, wavelength, and electric conductivity level.

scholarly journals Numerical Solutions of Heat and Mass Transfer Effects of an Unsteady MHD Free Convective Flow past an Infinite Vertical Plate with Constant Suction

1970 ◽  
Vol 5 (1) ◽  
pp. 27-36 ◽  
Author(s):  
V Ambethkar
Keyword(s):  
Mass Transfer ◽  
Finite Difference ◽  
Heat And Mass Transfer ◽  
Convective Flow ◽  
Vertical Plate ◽  
Numerical Solutions ◽  
Free Convective Flow ◽  
Finite Difference Technique ◽  
Constant Suction ◽  
Infinite Vertical Plate

The objective of this work is to study heat and mass transfer in an unsteady MHD free convective flow past an infinite vertical plate with constant suction numerically.  Dimensionless governing equations of the problem have been solved by using finite difference technique. Numerical solutions for temperature, velocity, concentration have been obtained for suitable parameters like Grashoff number, mass Grashoff number, Prandtl number and Schmidt number. Rate of heat transfer and mass transfer are studied. The results obtained are discussed with the help of graphs and tables to observe effect of various parameters concerned in the problem under investigation. Stability and convergence of the finite difference scheme is established. Key words: MHD, unsteady, constant suction, finite difference technique, Heat and mass transfer. doi:10.3329/jname.v5i1.1785 Journal of Naval Architecture and Marine Engineering Vol. 5, No. 1 (June, 2008) 27-36

Computer Simulation of the Response of Amperometric Biosensors in Stirred and non Stirred Solution

2003 ◽  
Vol 8 (1) ◽  
pp. 3-18 ◽  
Author(s):  
R. Baronas ◽  
F. Ivanauskas ◽  
J. Kulys
Keyword(s):  
Mathematical Model ◽  
Computer Simulation ◽  
Finite Difference ◽  
Mass Transport ◽  
Enzyme Reaction ◽  
Analyte Concentration ◽  
Amperometric Biosensors ◽  
Finite Difference Technique ◽  
Enzyme Layer ◽  
Biosensor Response

A mathematical model of amperometric biosensors has been developed to simulate the biosensor response in stirred as well as non stirred solution. The model involves three regions: the enzyme layer where enzyme reaction as well as mass transport by diffusion takes place, a diffusion limiting region where only the diffusion takes place, and a convective region, where the analyte concentration is maintained constant. Using computer simulation the influence of the thickness of the enzyme layer as well the diffusion one on the biosensor response was investigated. The computer simulation was carried out using the finite difference technique.

Modelling of Moisture Movement in Wood during Outdoor Storage

2001 ◽  
Vol 6 (2) ◽  
pp. 3-14 ◽  
Author(s):  
R. Baronas ◽  
F. Ivanauskas ◽  
I. Juodeikienė ◽  
A. Kajalavičius
Keyword(s):  
Experimental Data ◽  
Finite Difference ◽  
Climatic Conditions ◽  
Two Dimensional ◽  
Moisture Movement ◽  
Finite Difference Technique ◽  
Long Term Storage ◽  
Space Formulation ◽  
Term Storage

A model of moisture movement in wood is presented in this paper in a two-dimensional-in-space formulation. The finite-difference technique has been used in order to obtain the solution of the problem. The model was applied to predict the moisture content in sawn boards from pine during long term storage under outdoor climatic conditions. The satisfactory agreement between the numerical solution and experimental data was obtained.

On steady compressible flows with compact vorticity; the compressible Hill's spherical vortex

1998 ◽  
Vol 374 ◽  
pp. 285-303 ◽  
Author(s):  
D. W. MOORE ◽  
D. I. PULLIN
Keyword(s):  
Finite Difference ◽  
Compressible Flows ◽  
Numerical Solutions ◽  
Flow Direction ◽  
Fluid Velocity ◽  
Major Axis ◽  
Sonic Point ◽  
Euler Flow ◽  
Compressible Euler ◽  
Spherical Vortex

We consider steady compressible Euler flow corresponding to the compressible analogue of the well-known incompressible Hill's spherical vortex (HSV). We first derive appropriate compressible Euler equations for steady homentropic flow and show how these may be used to define a continuation of the HSV to finite Mach number M∞=U∞/C∞, where U∞, C∞ are the fluid velocity and speed of sound at infinity respectively. This is referred to as the compressible Hill's spherical vortex (CHSV). It corresponds to axisymmetric compressible Euler flow in which, within a vortical bubble, the azimuthal vorticity divided by the product of the density and the distance to the axis remains constant along streamlines, with irrotational flow outside the bubble. The equations are first solved numerically using a fourth-order finite-difference method, and then using a Rayleigh–Janzen expansion in powers of M2∞ to order M4∞. When M∞>0, the vortical bubble is no longer spherical and its detailed shape must be determined by matching conditions consisting of continuity of the fluid velocity at the bubble boundary. For subsonic compressible flow the bubble boundary takes an approximately prolate spheroidal shape with major axis aligned along the flow direction. There is good agreement between the perturbation solution and Richardson extrapolation of the finite difference solutions for the bubble boundary shape up to M∞ equal to 0.5. The numerical solutions indicate that the flow first becomes locally sonic near or at the bubble centre when M∞≈0.598 and a singularity appears to form at the sonic point. We were unable to find shock-free steady CHSVs containing regions of locally supersonic flow and their existence for the present continuation of the HSV remains an open question.

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