The airfoil effect generated by the arcuate shape 16 is effective to reduce {TAIL ~ the friction} between fibre fleece 4 and {HEAD ~ trough bottom} 9 
The airfoil effect generated by the arcuate shape 16 is effective to reduce { TAIL ~ the friction } between fibre fleece 4 and { HEAD ~ trough bottom } 9
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH