couple visqueux

CONT: Les gyroscopes 1 axe sont essentiellement constitués : d'une toupie [...]; d'un élément de cardan (anneau ou carter) reliant [delta] au boîtier de l'appareil, par l'intermédiaire de l'axe de sortie [...]; d'un détecteur d'écart [...]; d'un moteur-couple [...]. De plus, ils comportent éventuellement : un liquide amortisseur dans lequel baigne un carter étanche contenant la toupie; il en résulte l'application à ce carter d'un couple «visqueux» [...] étant un coefficient constant; en outre, la flottaison ainsi obtenue permet de soulager la liaison boîtier-carter, qui peut alors être constituée par des ensembles pivot-rubis; [...]

CONT: By drawing an analogy between linear and rotational dynamics, an equation describing the viscous torque acting on an object rotating in a fluid can be anticipated. Stokes' and Newton's models of a viscous drag force are commonly used to describe the damping force acting on an object moving linearly through a fluid. This experiment demonstrates that these models can be extended to describe the viscous torque that damps the rotation of an object in a fluid. When the rotating object is round, the fluid flow is laminar; hence, the viscous torque is proportional to the angular velocity to the first power, analogous to Stokes' model. However, when the rotating object is rough, causing the fluid flow to be turbulent, the viscous torque is proportional to the angular velocity to the second power, analogous to Newton's model. In addition, this experiment demonstrates that the proportionality constant between viscous torque and angular velocity is dependent on the shape of the object, as is the case in both Stokes' and Newton's models.