332 ME. L. F. RICHARDSON: APPROXIMATE ARITHMETICAL SOLUTION 



BOUNDARY CONDITIONS 



~| ORI&IN 



WHEN THE SURFACES ARE HORIZONTAL .VERTICAL, OR INCLINED AT 45* 



Fig. 6. 



The rather complicated conditions on the sloping surfaces require special reduction 

 to finite differences. Suppose the flank runs through a set of values of x as in 

 Table VI., then at the point "5, 



82 may be taken as {(OT) + (! l ) - (1 1) - (01 )}, 



. (13). 



Therefore the surface condition 



8 2 



^a + ^3 =0 Becomes = (0 I) + (1 1) - (00) - (10) . . 



TABLE VII. 

 TABLE VI. 



n 



In 



11 



10 



11 



o i 



Surface 



234 



-X 



In a similar way, at the point 0, '5 the second surface condition 



0== ^ + ^~ 2 ^ bec mes = (TT) + (lO)-(Ol)-(00)-2iz . (14). 

 The conditions on the front may be transformed in a similar way if necessary. 



