The disc shown in Fig. P6.81 has a diameter \(D\) of \(1 \mathrm{~m}\) and a rotational speed of \(1800 \mathrm{rpm}\). It is positioned \(4 \mathrm{~mm}\) from a solid boundary. The gap is filled with \(15{ }^{\circ} \mathrm{C} \mathrm{SAE} 10 \mathrm{~W}\) oil. Find the torque required to overcome the frictional resistance of the oil on the disc. Assume that the circumferential velocity \(\left(V_{\theta}\right)\) is linear across the gap at the each radius \(r\).

Figure P6.81

Transcribed Image Text:

-D- 4 mm