THEORETICAL BASIS FOR CALCULATING HYDRODYNAMIC RESISTANCE OF FLUID FLOW THROUGH THE THROTTLE OF THE SHOCK ABSORBER HOLE OF THE AIRCRAFT LANDING GEAR

Abstract

The movement of the shock absorber rod and the movement of the fluid through the throttle hole in the shock absorber under consideration are interconnected, therefore, to solve the problem, it is necessary to study the movement of the system. In the space in front of the plunger, the fluid is at rest, i.e. u=0, and in the throttle hole, the velocity of the fluid is u(r). Formula for calculating the force acting on the plunger as a result of the change in kinetic energy of the fluid flowing through the orifice, obtained from the condition of application to the plunger of Fkin, directed against the movement of the plunger and determined from the conditions of equality of the work of the applied force during the movement of the plunger over a distance ds and the amount spent on changing the kinetic energy of the flow during this period into the throttle opening. The article presents a solution to the differential equation of fluid motion through a cylindrical throttle opening and, on its basis, a calculation formula is obtained for determining the pressure drop required to overcome viscous resistance and the change in the kinetic energy of the fluid flow through the throttle opening of the gas-liquid shock absorber of the aircraft chassis. In laminar flow of liquid in a round pipe, the movement at a sufficiently large distance from the inlet section occurs according to parabolic laws. As it moves away from the outlet section, under the influence of viscosity forces, the layers of liquid located far from the walls will slow down, resulting in a parabolic flow regime. It has been established that the length of the initial section of the throttle hole is quite large, which must be taken into account when calculating the hydrodynamic resistance to liquid flow.