By Pascal Chossat
1. 1 A paradigm approximately 100 years in the past, Maurice Couette, a French physicist, de signed an equipment along with coaxial cylinders, the gap among the cylinders being jam-packed with a viscous fluid and the outer cylinder being turned around at angular speed O2. the aim of this test was once, keep on with ing an concept of the Austrian physicist Max Margules, to infer the viscosity of the fluid from measurements of the torque exerted by way of the fluid at the internal cylinder (the fluid is thought to stick to the partitions of the cylinders). at the least whilst O isn't really too huge, the fluid move is sort of laminar and a couple of the tactic of Couette is efficacious as the torque is then proportional to a hundred and ten , the place II is the kinematic viscosity of the fluid. If, notwithstanding, O is two 2 elevated to a really huge price, the movement turns into finally turbulent. many years later, Arnulph Mallock designed an analogous equipment yet allowed the interior cylinder to rotate with angular pace 01, whereas O2 = o. The shock used to be that the laminar circulation, referred to now because the Couette stream, was once no longer observable while zero handed a definite "low" serious worth Ole, even 1 notwithstanding, as we will see in bankruptcy II, it's a answer of the version equations for any values of zero and O .