to the ambient as shown in fig1 the inlet gas pressure is higher than the outlet gas pressure and the resulting pressure differential provides the coolant flow to the stator 14 the holes 34 provide for suction through which exits the stator 14 is indicated by arrows 42 the type of fluid flow 39 s regime is identified by a reynolds number the reynolds number re is a dimensionless number u03c1v1 u03bc where v is the fluid velocity u03c1 is the density u03bc is the viscosity and 1 is a characteristic dimension of the system the value of re indicates the regime of the fluid flow when a certain re is exceeded instable flow can be generated for example a configuration such as shown in fig1 i e the viscous flow between two concentric cylinders of which the inner cylinder is in motion and the outer cylinder is at rest i e couette flow demonstrates an example of a typical unstable flow stratification caused by centrifugal forces when such flow instabilities occur due to reaching a certain critical re certain toroidal flow vortices known as taylor vortices can appear whose axes are located along the circumference of the inner cylinder and which.