Therefore, an analysis based upon a purely elongational flow, such as the sink flow analysis of Metzner and Metzner , is expected to have a large error in the estimated entrance loss and elongational viscosity.
6), such that the difference between the entrance loss predicted by a finite element simulation and the corresponding experimental data for a range of flow rates in capillary or slit rheometer is minimized.
To determine the entrance loss for axisymmetric flow, Bagley plots  were prepared using the pressure data from the capillary experiments.
For LDPE1, the entrance loss data from capillary and slit rheometers are shown in Figs.
The design coefficients derived in this study were the entrance loss coefficients, which are the numbers multiplied by the velocity head to estimate the entrance energy loss for a culvert operating in outlet control where the headwater depth is influenced by tail water and friction in the culvert as well as the entrance loss.
The values for the entrance loss coefficient for the field-cast models with straight wingwalls were almost identical for the single-, double-, triple-, and quad-barrel models and averaged 0.
The average entrance loss coefficient increased from 0.
Multiple-barrel models with flared wingwalls, on the other hand, were slightly less hydraulically efficient for the outlet control tests where the entrance loss coefficient varied from 0.
3, combined with this entrance loss
, is an accurate predictor of the behavior of the guide.
Extra pressure loss and vortex length predicted by a finite element simulation of entrance loss are compared with the corresponding predictions from Binding's approximate analysis.
By separately calculating the pressure drop due to shear and elongational flow near an abrupt contraction, Cogswell  developed analytical expressions for an approximate calculation of entrance loss in a fluid with different power-law indices for shear and elongational viscosities.
The effects of flow rate and elongational viscosity on entrance loss are analyzed later in this paper.