ABSTRACT
If a1 = a2 = 0, the fluid compressibilty is not taken into account. In order to study the dynamic flow force , an approximate triangular impulse force is used to act on the poppet element in this paper, the output is the displacement of poppet element, and then the transfer function is the rigidity transfer function M (s) = 1/G(s). The experimental result is shown in Fig. 4, in which the real line is the curve by Eq. ( 4) , the dot line is that unconceming the fluid compresibility (Assume a1 = a2 = 0 in Eq. ( 4) ). It can be known that:
( 1 ) The amplitude of frequency response does not change when f < 4OHz, which means that the steady state flow force is dominant. The amplitude is gradually getting small as 40Hz<f<200Hz and large as the f >200Hz, these variations mean that the transient flow force increases gradually.
