This section discussed influence of torsional vibration amplitude of average axial viscous force
. The ROP was equal to 7 m/h.
Calculated results for the oil viscous force
[F.sub.vs] given by Equation 16 and the solid shearing force [F.sub.vs] given by Equation 25 are shown by solid and broken lines, respectively, in Figure 11c.
The gravity number relates the effect of gravity force to viscous force
according to (2).
On the basis of keeping the similarity criterion [[pi].sub.2] (gravity and capillary force ratio) and [[pi].sub.3] (gravity and viscous force
ratio), change the value of [[pi].sub.1] to optimize driving pressure, as shown in Table 5.
This may be due to the fact that when the Re number becomes lower than 0.662, the viscous forces
will dominate (see Fig.
 Brinkman H.C., The calculation of viscous force
exerted by a flowing fluid on a dense swarf of particle, J.
B8 and 29, it is also of importance to notice that at fixed BUR, an increasing gas pressure difference has the same effect with an increasing axial drawing by the nip rolls; hence, it should be expected that the film would be able to resist forces from the air jet for larger values of the viscous force
ratio and, therefore, the loss of solutions of the thin film equations will be postponed at higher viscous ratios.
You can eliminate the viscous force
by operating the SFM in vacuum or in an aqueous environment.
 Brinkman H.C (1948): A Calculation of the viscous force
eternal by a flowing fluid on a dense swarm of particles.
Both Fuchigami (10) and Carvalho (11) reported that the minimum wet thickness, which is defined as the lowest stable coating thickness of a coating solution at specific operating conditions, is proportional to the tension number defined as the ratio of fluid viscous force
to web tension.
There are three competing forces, i.e., surface tension, viscous force
to pull the solution deposited on the moving substrate, and the fluid inertia impinging on the moving substrate for the coating flow.
in the coating bead, [F.sub.v] = [mu](V/H): this is the force required to pull the liquid in the coating bead onto the moving web.