Assume that the pores are arranged regularly (Fig.1,a) and the distance 2r1 between pores is sufficiently large so that the interaction between the pores can be neglected. Therefore, only one pore with the adjoining part, called the control cell, should be studied. A cross-section of the control cell on the sliding surface and opposite non-porous surface is shown in Fig.1b; each pore has radius r0; the gap between surfaces equals h0; and the direction of the friction force is opposite to the lower surface motion.
Pore cell geometry: regular pore arrangements, computer produced image (a); semicircular profile of the pore (b)