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General relativity describes the physical force of gravity and its relation with the space-time structure. The fundamental physical insight behind the theory of general relativity is that the effects of acceleration cannot be distinguished from those of gravity. The presence of matter changes the geometry of space and acceleration is experienced in relation to that geometry. In particular, the geometry of space and time is dynamically governed by physical laws that are not independently given. Such a case is the fluid turbulence which remained unexplained for over fifty years within the framework derived from the classical Navier-Stokes theory. The physical and mathematical problem of the genuine turbulence remains an unsolved one. This paper considers the turbulence as a manifestation of non-Newtonian behavior induced by the gravity-like accelerations at the beginning of motion. The fluid particles with high accelerations exhibit in wall-bound flows with large Reynolds number a sort of structure-less, background turbulence. It is shown that the relativistic viewpoint may solve the present paradigmatic crisis of turbulence. [ABSTRACT FROM AUTHOR]

The application of the Coandă effect to the directional control of a jet or thrust is presented. Deviation of the thrust force by direct flow can be achieved by using the Coandă effect to change the angle of the primary jet engine exhaust nozzle. Major interest in the study of this phenomenon is caused by the possibility of using this effect for aircrafts with short take-off and landing, for thrust vectoring. The numerical investigations are performed using a RANS solver with an adequate turbulence model, showing a change of the jet direction. Thus, the conditions and the limits within which one can benefit from the advantages of Coandă-type flows are determined. [ABSTRACT FROM AUTHOR]