*3.4. Oscillation Characteristics Considering Motion Coupling of the Main Valve*

In this section, the influence of the main valve on the flow field will be considered to establish a more realistic flow field in the servo valve. Similarly, the two-dimensional model is still used in this chapter. The flow field of the whole valve is shown in Figure 17.

**Figure 17.** Watershed model of the servo valve considering the effect of the main valve.
