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