The pressure on a propeller blade surface rotating at a constant angular 

 velocity, fi = -Q.±_ (see Figure 1), in an axisymmetric onset flow can be expressed 

 as (see Appendix) : 



^p{V-V - (V^)^ - rV} + p, (9) 



where V = total velocity; V = V + rf2e„ + V + V 

 — ^ — -w — e ^ — o 



V = axisymmetric onset flow; V =Vi+Ve + V_e. 

 ^w -^ — w X— i^r 6—8 



V = perturbation velocity due to the propeller blades and 



their wakes 



V = perturbation velocity due to the other sources such 



as appendages or lifting surfaces 



(i^,e^ ,6^) = unit vectors in the axial, radial and tangential 

 directions in the cylindrical coordinate system 

 (x,r,6) rotating with the propeller 



The subscript. A, in Equation (9) indicates a point on the same streamline where 

 the pressure is computed. 



If a propeller is operating in a uniform onset flow with only an axial compo- 

 nent and with no other sources of disturbance, i.e., the flow condition for all 

 the experimental measurements correlated in this report, the pressure will be: 



p = - Yp{V-V - vj - r^n^} + p^ (10) 



where V = V i + rf^e. + V , and p is the pressure at any point far upstream of a 

 — X— — G--p°o *^ 



propeller. 



We define the pressure coefficient C as 



P 



P ~ Poo 1 2 2 2 



C = ^ = - -^ (V-V - V^ - rV) (11) 



where V is a reference speed. In PSP, three options are given for V ; one is the 

 local inflow speed to the blade section, /y2 ^ (ZTrnr)^ > the other two options are 

 the local inflow speed at r = 0.7R and the ship speed. 



