*4.2. The E*ff*ect of Texture Size (S)*

In this section, to study the effect of size on the coefficient of friction for starved lubricated contacts, the texture depth and pitch are set as constant, and the size is changed. For three different texture size parameters (*S*), the coefficient of friction is calculated. In Figures 13 and 14, the simulation results show the effect of different values for texture size-based-starved and non-starved lubrication for grooves and chevrons. In Figure 13a, in the case of groove patterns when the size is around 100 μm, the friction force has the lowest value. In Figure 13b, the limited input film thickness is applied in order to simulate the starvation. The results in Figure 13b show that the calculated Stribeck curves for different values of texture size are merging in the case of starved lubrication. Texturing properties for calculations of Figures 13 and 14 are shown in Table 3.

**Figure 13.** Stribeck curves as a function of cavity size (*S*) for grooves when the lubrication is: (**a**) Non-starved, (**b**) starved, and *hoil* = 10 μm.

**Figure 14.** *Cont*.

**Figure 14.** Stribeck curves as a function of cavity size for chevrons when the lubrication is: (**a**) Non-starved, (**b**) starved, and *hoil* = 10 μm.

**Table 3.** Texturing properties.


In Figure 14a, in the case of a chevron pattern similar to the groove pattern, the lowest coefficient of friction in the case of non-starved lubrication is achievable when the size is around 150 μm. Also for this case, starved lubrication results in the merging of the curves as shown in Figure 14b. Consequently, as mentioned and achieved from Figure 14, changing the size parameters has an influence on the coefficient of friction, but this effect is limited with respect to values close to the optimum value for this parameter.
