Table 2: Effective length adopted for the approaches 2 and 3.

Approach	Non-circular Patterns	Circular Patterns
2	leff,i+2.m+0.625?ei             leff,i+0.5pi        2?m+0.625?ei+ei,s             ei,x+0.5?pi           4?m+1.25?ei       2?m+0.625?ei+0.5?pi	π?m+2?e1,s           2?π?mπ?m+pi e1,s+pi
3	2?m+0.625?ei+pi/2        m+ei?k+0.5?pi+g/2	2?π?m           π?m+pi
with i=1,2