Аннотация:
We introduce and study so-called normal parabolic equations in order
to understand better properties of equations of Navier–Stokes type.
Semilinear parabolic equation is called normal parabolic equation (NPE)
if its nonlinear term B satisfies the condition: for each vector-function
v vector-function B(v) is collinear to v. This condition means that solutions
of NPE does not satisfies energy estimate “in the most degree”.
For 3D Helmholtz equations we derive normal parabolic equations
(NPE), which nonlinear term B(v)is orthogonal projection in L2 of nonlinear
terms for Helmgoltz equation on the line generated by v.
NPE corresponding to Burgers equation is obtained similarly. The structure of
dynamical flow corresponding to these NPEs will be discribed.
For NPE corresponding to Burgers equation we construct nonlocal feedback
stabilization to zero of solutions by starting or impulse controls supported
in an arbitrary fixed subdomain of the spatial domain. The last
result can be applied to stabilization of solutions for Burgers equations.