Using polynomial regression, {TAIL ~ an empirical relationship} can be found between {HEAD ~ the density} and pressure drop 
Using polynomial regression , { TAIL ~ an empirical relationship } can be found between { HEAD ~ the density } and pressure drop
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH