To further correct the measured pressure for loading, a second-order effect of 



inflow speed was investigated. Conditions were run at design J over a range of 



inflow speeds. Figure 8 shows the variation of C over ranges of inflow speed at 



pL 



design J. Again, all test spots are shown, including repeat runs, and a third-order 



polynomial was fitted to the measured loading coefficients over the range of V . 



R 



Even with relatively expanded scales for C (see Figure 8), the variation with V 



P J-i Li 



was small except at two gage locations. To adjust for loading effects as accurately 

 as possible, the second-order effect of speed was considered in a fashion similar to 

 the first-order effect of advance coefficient. In this case the curve-fit polynomial 

 in Figure 8 was used to analytically describe the variation of C with V at constant 

 design J, 



V (J des' V = A + BV R + CV R 2 + DV R 3 



where A, B, C, D, are polynomial coefficients. The above quantity was then sub- 

 tracted from the measured pressure coefficient to correct for the second order load- 

 ing effect due to speed, as 



C (J) = C (J) - C (J) - C (J. ,V ) 

 pcor p pL pL des R 



To avoid accounting for the loading effect twice in the two loading terms above, 

 C (J, ,V ) was added to the right side of the above equation, where V was the 

 primary inflow speed tested in the range of J runs, as shown in Figure 7. Rewriting 

 the above equation, one obtains 



C (J,V n ) = C (J,V._) - C _ (J,V„ ) - C _ (J, ,V n ) + C _ (J, ,V D ) 

 pcor ' R p ' R pL ' Ro pL des' R pL des' Ro 



Each pressure coefficient term is a function of both J and V , where, 



1. C (J,V ) is the polynomial function from Figure 7 

 pL Ro 



2. C _ (J , .V^) is the polynomial function from Figure 8 

 pL des R 



14 



