S. L. Arsenjev

Physical-Technical Group

Dobroljubova Street, 2, 29, Pavlograd Town, Dnjepropetrovsk region, 51400 Ukraine

The overcoming of a mechanics problem on origin of secondary jet flows, on dynamics of its development and interaction with the main stream of the viscous fluid is reached by means of elucidation of the energy distribution in the stream at its interaction with the flow system walls and a body surface. In contrast to a traditional conception on a total head of a fluid stream in a pipe as a sum of a velocity head and a static pressure, it is ascertained that this sum is only longitudinal component of the stream total head vector. A new conception is stated and the expressions for quantitative evaluation of radial and tangential components of the stream total head vector and for angle of its deflection from the stream axis are produced. The new approach has allowed rationally explaining the causes of origin of the secondary jet flows and dynamics of its interaction with the main stream in various cases. Thereby with the taking into account of previous articles of the author the necessary theoretical preconditions has been created for a working out of the modern physically valuable apparatus for mathematical modeling of the real – viscous – fluid motion in any problems of hydromechanics and gas dynamics.

**PACS:** 01.55.+ b; 47.10.+ g; 47.15.Cb; 47.27.Lx; 47.40.Dc; 47.60.+ i; 47.85.Dh; 47.85.Gj

### Modern fluid motion physics: the total head vector of the real fluid stream