Fluid mechanics (FM) is a branch of science dealing with the investi-
gation of flows of continua under the action of external forces. The
fundamentals of FM were laid in the works of the famous scientists, such
as L. Euler, M. V. Lomonosov, D. Bernoulli, J. L. Lagrange, A. Cauchy,
L. Navier, S. D. Poisson, and other classics of science. Fluid mechanics
underwent a rapid development during the past two centuries, and it now
includes, along with the above branches, aerodynamics, hydrodynamics,
rarefied gas dynamics, mechanics of multi phase and reactive media, etc.
The FM application domains were expanded, and new investigation methods
were developed. Certain concepts introduced by the classics of science,
however, are still of primary importance and will apparently be of
importance in the future. The Lagrangian and Eulerian descriptions of a
continuum, tensors of strains and stresses, conservation laws for mass,
momentum, moment of momentum, and energy are the examples of such
concepts and results. This list should be augmented by the first and
second laws of thermodynamics, which determine the character and
direction of processes at a given point of a continuum. The availability
of the conservation laws is conditioned by the homogeneity and isotrop-
icity properties of the Euclidean space, and the form of these laws is
related to the Newton's laws. The laws of thermodynamics have their
foundation in the statistical physics.