2. Noise

2.1 Direct and induced noise

Hydraulic components and circuits are sources of direct noise, as they are the seat of naturally noisy phenomena such as friction, shocks, cavitations, turbulence, etc. They are also the source of indirect or induced noise, as they cause mechanical vibrations. They are also the source of indirect or induced noise, as they give rise to mechanical vibrations, notably pressure vibrations and fixing vibrations. One difficulty in dealing with noise problems in hydraulic circuits is to separate what is radiated directly and what is the consequence of vibrations transmitted to structures.