Library Subscription: Guest
ICHMT DL Home Current Year Archives Executive Committee International Centre for Heat and Mass Transfer


DOI: 10.1615/ICHMT.2012.CHT-12.200
pages 335-355

Juan I. Ramos
Escuela de Ingenierias Industriales, Universidad de Malaga, Dr. Ortiz Ramos, s/n 29071 Malaga, Spain


Relaxation phenomena in two-dimensional nonlinear activator-inhibitor processes governed by reaction-diffusion equations are studied by means of a time-linearized implicit method based on the time-linearization and discretization of the time derivatives that result in linear elliptic equations at each time level. These two-dimensional elliptic equations are then factorized in terms of one-dimensional operators which are discretized by means of second-order accurate finite differences, and the second-order approximate factorization errors are neglected. The numerical method uses the dependent variables and its first-order derivative as unknowns, is self-starting and, for relaxation times equal to zero, reduces to the well-known second-order accurate, time-linearized Crank-Nicholson procedure; therefore, the method may be used to study conventional multi-dimensional reaction-diffusion equations as well as relaxation phenomena in reaction-diffusion characterized by hyperbolic equations. Applications of the method to activator-inhibitor problems governed by reaction-diffusion equations with relaxation and in the presence of a solenoidal velocity field that corresponds to a modified Lamb-Oseen vortex indicate that, for small vortex strengths, the spiral wave is almost unaffected by the flow except near its tip, whereas for strong vortices and core radii on the order of the drift of the spiral wave, substantial changes in the spiral wave morphology are observed depending on whether the vortex rotates in a clockwise or counter-clockwise direction. For counter-clockwise rotations, it is shown that spiral wave arm may exhibit a bulge in the activator concentration on the wave's inner side, while the inhibitor concentration may exhibit a bulge in the inner side and a valley in the outer side. For clockwise vortex motion, it is shown that the spiral wave may thicken on account of the opposing flow field and its tip may acquire a pointed feature. It is also shown that, for the conditions considered in this work, the spiral wave does not break up; neither does it form tiles and stripes as it has been found with other velocity fields.

ICHMT Digital Library

Bow shocks on a jet-like solid body shape. Thermal Sciences 2004, 2004. Pulsed, supersonic fuel jets - their characteristics and potential for improved diesel engine injection. PULSED, SUPERSONIC FUEL JETS - THEIR CHARACTERISTICS AND POTENTIAL FOR IMPROVED DIESEL ENGINE INJECTION
View of engine compartment components (left). Plots of temperature distributions in centreplane, forward of engine (right). CHT-04 - Advances in Computational Heat Transfer III, 2004. Devel... DEVELOPMENT AND CURRENT STATUS OF INDUSTRIAL THERMOFLUIDS CFD ANALYSIS
Pratt & Whitney's F-135 Joint Strike Fighter Engine under test in Florida is a 3600F class jet engine. TURBINE-09, 2009. Turbine airfoil leading edge stagnation aerodynamics and heat transfe... TURBINE AIRFOIL LEADING EDGE STAGNATION AERODYNAMICS AND HEAT TRANSFER - A REVIEW
Refractive index reconstructed field. (a) Second iteration. (b) Fourth iteration. Radiative Transfer - VI, 2010. Theoretical development for refractive index reconstruction from a radiative ... THEORETICAL DEVELOPMENT FOR REFRACTIVE INDEX RECONSTRUCTION FROM A RADIATIVE TRANSFER EQUATION-BASED ALGORITHM
Two inclusion test, four collimated sources. Radiative Transfer - VI, 2010. New developments in frequency domain optical tomography. Part II. Application with a L-BFGS associated to an inexa... NEW DEVELOPMENTS IN FREQUENCY DOMAIN OPTICAL TOMOGRAPHY. PART II. APPLICATION WITH A L-BFGS ASSOCIATED TO AN INEXACT LINE SEARCH