This book addresses the concepts of unstable flow solutions convective instability and
absolute instability with reference to simple (or toy) mathematical models which are
mathematically simple despite their purely abstract character. Within this paradigm the book
introduces the basic mathematical tools Fourier transform normal modes wavepackets and their
dynamics before reviewing the fundamental ideas behind the mathematical modelling of fluid
flow and heat transfer in porous media. The author goes on to discuss the fundamentals of the
Rayleigh-Bénard instability and other thermal instabilities of convective flows in porous media
and then analyses various examples of transition from convective to absolute instability in
detail with an emphasis on the formulation deduction of the dispersion relation and study of
the numerical data regarding the threshold of absolute instability. The clear descriptions of
the analytical and numerical methods needed to obtain these parametric threshold data enable
readers to apply them in different or more general cases. This book is of interest to
postgraduates and researchers in mechanical and thermal engineering civil engineering
geophysics applied mathematics fluid mechanics and energy technology.
