Figure 1 demonstrates the how a traditional ejector was used to get polymer into the boundary layer of a vessel.
Figure 1: Test of Traditional Ejector
Figure 2 demonstrates the traditional ejection technique. With the traditional technique there is what has been referred to as "boundary layer blow-off" caused by material that gets ejected with such force that it blows through the boundary layer. The traditional method is not a good Ejection technique as it creates drag at the point of ejection, the polymer material does not come back into the near wall region where it will provide skin friction reduction until far downstream, and vast quantities of polymer fluid are required since ta large fraction of the polymer is lost into the ocean where it never does any skin friction reduction.
But it is important to remember that while these traditional techniques were wasteful of the expensive polymer, they still were able to get considerable amounts of skin friction reduction. Unfortunately, because the traditional techniques were so wasteful, Skin Friction Reduction (SFR) could only be considered for short bursts of speed, either to quickly engage or retreat from the enemy.
Figure 2: Traditional Ejection Technique
Figure 3 demonstrates the Cortana Fluidics Ejector's ability to eject fluid at an angle greater than 90 degrees from the horizontal while maintaining the fluid at the wall as it moves downstream.
Figure 3: Test of Cortana Fluidics Ejector
Figure 4 demonstrates the Cortana Fluidics Ejector and its ability to be non-disruptive as the fluid is ejected. The polymer fluid id "preconditioned" that is the polymer molecules are elongated so they can begin to quell turbulence immediately upon ejection. Because the Cortana Fluidics Ejector is non-disruptive this technique enables skin friction reduction immediately, i.e. it does not induce drag as in the traditional ejection techniques. The Cortana Fluidics Ejector also does not have a diffusion problem anywhere near as severe as the Traditional Ejector. Therefore, the Cortana Fluidics Ejector can ejector lower concentrations of polymer and at much reduced flow rates compared to the Traditional Ejector systems and achieve higher levels of skin friction reduction. This means that coupled with the AHS (Additive Handling System) polymer ejection does not have to be used just for burst speed, but can now be considered for anytime one wants to enjoy reduced fuel consumption and/or higher speeds for the same installed power.
Figure 4: Cortana Fluidics Ejector
Figure 5 shows the Cortana Fluidics Ejector operating in the Sea Flyer while it was in dry dock. Seawater alone was ejected just to discern if all of the ejectors were operating properly (i.e. no polymer was used). Note how the pressure side (bottom) ejectors on the lifting body are ejecting water straight back along the body with minimal disruption.
Figure 5: Cortana Fluidics Triple Slot Ejector
Figure 6 shows the technique used by the patented Cortana fluidics ejector for getting material into the boundary layer. The free stream seawater going over the hull of the vessel is depicted by f1. The Sacrificial Ejector ejects bubbles or bubbly polymer out of the ejector denoted by f2. The ejectant from Sacrificial Ejector (f2) is of a low polymer concentration and quells the turbulence upstream of the Primary Ejector fluid from f3. The Primary Ejector (f3) emits the highest concentration of polymer fluid at at the highest flow rate of the three ejectors. The Secondary Ejector emits a low flow rate of seawater or with a very small amount of polymer from f4. The Secondary Ejector is used to get the high viscosity Primary Ejectant away from the wall.
Figure 6: Cortana Fluidics Triple Slot Ejector
Figure 7 shows the Cortana fluidics ejector undergoing Computational Fluid Dynamics modeling.
Figure 7: CFD of Cortana Fluidics Ejector[1]
Proceed to Additive Handling System
