7.6. Define the frictional effects in a fan impeller in terms of a total pressure loss, opr. Using the concept of a force coefficient, or "loss coefficient", we can specify Opras Spr-1/2pW, CwNB where Cwb is a blade (or wake) loss coefficient and Ng is the number of blades. Use the formulation for y in Problem 7.4 to show that the losses may be written as by loss = 8p:/(1/2pU22) =((DD) + ?) Nwb. where Oy loss is the viscous correction to Videal