Abstract

International audience; Water hammer (WH) phenomenon may produce various undesired effects in pipelines. Dynamic interaction between the liquid and the structure is known to influence the transient pipe flow parameters in non-rigid systems. One can expect that due to basic energy conservation considerations the energy outflow from the liquid to the elastic structure would result in lowering of WH pressures. However, this effect is not unambiguous and is not clearly and uniquely explained in literature. Thus, its proper understanding is of great practical importance. In the paper the authors try to examine these effects mainly on the basis of experimental results acquired from measurements at a special test rig designed and constructed at the Institute of Fluid-Flow Machinery in Gdansk. The main part of the rig is a cooper pipeline of the length of about 59m, fixed to the floor with a number of elastic supports. WH runs were generated, measured and analyzed for supports of varying stiffness. Pipeline free vibrations induced by mechanical shock were measured as well. The conclusions have been found and they are presented in the paper. Still, a very important part of the job was to find the physical interpretation and explanation of the results, which allows for understanding of that phenomenon.

Abstract

International audience; In this paper, a distribution vehicle, which can be equipped with many actuators as wheel electric motors and steering wheels and which is supported to follow a given trajectory, is chosen as an application for determining the optimal vehicle configuration and expected energy gains. The different vehicle configurations are formed by the amount and the position of these actuators, defining 16 different architectures. From the total efforts at the gravity center of the vehicle, the control allocation of the nonlinear system under nonlinear constraints is used to determine the torque of the actuated wheels and the angle of steered wheels. The same objective function is used for actuation allocation while different constraints assumed for describing each vehicle architecture. Energy losses in the tire-road contact zone, necessary power for steering system, kinetic energy of the vehicle during the maneuver and the consumption energy are estimated for comparison purposes in the case of lane changing. Along with that, the performance of the vehicle's steering system was also assessed in the case of a different torque of the electric motors.