wide nozzle. The depth of element’s flow passage was kept at 
1/4 inch. The mixture jet in each stage is directed by a curved 
wall conforming to the curvature of a reattaching jet issuing 
parallel to a flat plate with an offset of 4 inches. This boundary 
was determined from flow governing equations given in Appendix 
A. The element was designed to handle 0.8 gpm of water flow 
through each stage. Each stage was provided with oil collecting 
chambers located directly on its separation bubble zone. The 
oil outlet line on each oil chamber was provided with a hand 
controlled valve for outgoing oil flow adjustment. 
The element was tested using the setup shown in Figure 
4. The tests were conducted by varying the oil in the mixture 
from 6 to 8%. The test results indicate that each stage separated 
about 50% of the oil from its input flow. The effluent at the 
third stage outlet contained about 1% oil. The oil being extracted 
had about 3 to 5% water. Figure 11 shows the element undergoing 
tests. The flow pattern through the element is shown in Figure 
12. The accumulation of oil in the collecting chambers and 
the separated oil flowing through the outflow lines are shown 
in the flow record. 
DISCUSSION 
Jet Velocity Distribution 
As mentioned earlier, the mixture jet during its attachment, 
develops a centrifugal acceleration. It was assumed prior to 
conducting the tests that the lateral acceleration so induced 
would force most of the oil in the jet into the separation 
bubble zone of the flow. The observed flow patterns through 
the experimental models on the other hand revealed that the 
oil particles were distributed uniformly over the entire cross- 
section of the jet. This important observation can be explained 
from theoretical considerations discussed in Appendix A. 
Consider the reattaching jet velocity profile described 
by Equation 2: 
Bisa ri 2 oy 
4o(sts ) sts 
u(s,y) (2) 
O 
where the various symbols are defined in Appendix A. The width 
of a two-dimensional jet expanding into a similar fluid at 
any axial location can be derived easily from a linear relationship 
given in References 4 and 5. The half width, yy of the jet 
is given by 
