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Embodiments of the invention provide a method, device, and turbopump configured to suppress higher order cavitations at an inducer tip in a turbopump. An inducer having a tip is rotated, and a first flow is induced axially through the inducer at a first velocity. A second fluid flow is introduced to

Embodiments of the invention provide a method, device, and turbopump configured to suppress higher order cavitations at an inducer tip in a turbopump. An inducer having a tip is rotated, and a first flow is induced axially through the inducer at a first velocity. A second fluid flow is introduced toward a tip of the inducer substantially parallel to the first fluid flow at a second velocity that is greater than the first velocity, such that back flow through the tip of the inducer is reduced.

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What is claimed is: 1. A method for suppressing cavitation at an inducer blade tip in a pump, the method comprising: rotating an inducer having a tip clearance; inducing a first fluid flow axially through the inducer at a first velocity; and introducing a second fluid flow toward the tip clearance

What is claimed is: 1. A method for suppressing cavitation at an inducer blade tip in a pump, the method comprising: rotating an inducer having a tip clearance; inducing a first fluid flow axially through the inducer at a first velocity; and introducing a second fluid flow toward the tip clearance substantially parallel to the first fluid flow at a flow rate with a second velocity, greater than the first velocity, such that back flow through the tip clearance of the inducer is reduced, wherein introducing the second fluid flow includes introducing the second fluid flow through a substantially cylindrical housing having a rearward-facing step configured to introduce the second fluid flow toward the tip clearance of the inducer. 2. The method of claim 1, wherein the second fluid flow is introduced into a boundary layer. 3. The method of claim 2, wherein introducing the second fluid flow includes occluding the first fluid flow from the tip clearance. 4. The method of claim 1, wherein the second velocity is substantially 1.5 to 2 times the first velocity. 5. The method of claim 1, wherein the second velocity is selected to minimize the relative fluid angle. 6. The method of claim 1, further comprising directing the second flow to energize a boundary layer flow. 7. The method of claim 6, wherein the energizing of the boundary layer flow is sufficient to eliminate a tip back flow near the leading edge. 8. The method of claim 6, wherein directing of the second flow includes directing to optimize the effective incidence angle at the inducer tip. 9. A device for suppressing cavitation at an inducer blade tip in a pump, the device comprising: a substantially cylindrical housing configured to receive an inducer therein, the inducer being configured to induce a first fluid flow axially through the housing at a first velocity; and an inductor configured to introduce a second fluid flow at a flow rate toward a tip clearance of the inducer substantially parallel to the first fluid flow at a second velocity that is greater than the first velocity, such that back flow through the tip clearance of the inducer is reduced, wherein the substantially cylindrical housing further defines a rearward-facing step configured to introduce the second fluid flow toward the tip clearance of the inducer. 10. The device of claim 9, wherein the second fluid flow is introduced into a boundary layer flow along an inner wall of the cylindrical housing. 11. The device of claim 9, wherein the inductor includes an inlet duct. 12. The device of claim 11, wherein the inlet duct is configured to introduce the second fluid flow at a direction substantially parallel to the first fluid flow. 13. The device of claim 12, where the inlet duct is further configured to introduce the second fluid flow at the flow rate into a tip clearance. 14. The device of claim 9, wherein the second velocity is substantially 1.5 to 2 times the first velocity. 15. The device of claim 9, wherein the flow rate is substantially equal to a tip clearance potential flow rate. 16. The device of claim 9, wherein the flow rate is optimized to minimize the tip vortex. 17. The device of claim 9, wherein the flow rate is optimized to minimize higher order oscillations. 18. The device of claim 9, wherein the second flow energizes a boundary layer substantially along the inner wall. 19. The device of claim 9, wherein the rearward facing step includes an annular slot at the step. 20. An inducer axial flow stage for a pump, the inducer axial flow stage comprising: an inducer having blades tangentially arranged about an axis, the blades having an outer tip, a pressure side, a suction side, a blade entrance angle and camber to motivate a first flow of a fluid at a first velocity upon rotation of the inducer; and a housing defining a tunnel, the tunnel being coaxial with the inducer axis and having a cylindrical wall spaced apart from the outer tip of the blades, an upstream opening, and a downstream opening, the tunnel being configured to contain the inducer between the upstream opening and the downstream opening in a plane perpendicular to the axis, the cylindrical wall further defining an annular slot substantially at a juncture of the cylinder inner wall and the inducer blade tips, wherein the cylindrical wall further defines a step at the annular slot, the step extending toward the downstream opening, the step being configured to occlude the tip clearance. 21. The pump of claim 20, wherein the cylindrical wall is spaced apart from the outer blade tip to define a tip clearance. 22. The pump of claim 20, wherein the annular slot is configured to introduce a second flow of fluid at a flow rate. 23. The pump of claim 22, wherein the second flow energizes a boundary layer substantially at the cylindrical wall. 24. The pump of claim 22, wherein the second velocity is at a second velocity substantially parallel to the axis. 25. The pump of claim 24, wherein the second velocity is selected to minimize reverse flow at the tip clearance. 26. The pump of claim 24 wherein the second velocity is optimized to reduce a relative fluid angle. 27. The pump of claim 24, wherein the flow rate is optimized to minimize a tip vortex. 28. The pump of claim 24, wherein the flow rate is optimized to minimize higher order oscillations.