In one preferred embodiment, {HEAD ~ an air blast} is directed through the porosity created by tensioning the fabric to impinge upon the underlying layer of {TAIL ~ fabric} 
In one preferred embodiment , { HEAD ~ an air blast } is directed through the porosity created by tensioning the fabric to impinge upon the underlying layer of { TAIL ~ fabric }
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL