This means that turbulence is a condition that is too complex for it to be defined only by specifying rotv, can only be considered with additional assumptions or data.
The main purpose of this section is to clarify the assumptions that underlie the Navier-Stokes equations. These equations are the most widely used in fluid mechanics, and it is important to use them correctly in the complex situations that happen in reality.
The most fundamental assumption, without which these equations can not be obtained, is that the voltage (power) in the fluid are related linearly and immediately strain rate (bias). Thus, twice the rate of deformation corresponds to twice the power, and the liquid does not preserve evidence of previous movement: the forces arise or disappear immediately when started or stopped deforming motion. Viscous forces there because of the motion of molecules, and this means that the velocity of the molecules is much greater than the differences of the different velocities of the fluid particles, which is of course true for ordinary movements of the atmosphere.
Strain rate at the point in a fluid can be expressed as the rate of change of the angles between the three (coordinate) levels in liquid particles that are orthogonal to the start of the deformation. The value of dw / dy is a measure of the speed of rotation around the x-axis particles on the y axis. If we add to dv / dz derivative dw / dy, which is the speed of rotation around the x-axis particles on the z axis, the amount will be equal to the speed, change the angles between the straight lines, initially coinciding with the axes of y and z. This value is one of the components of the strain rate. |