FEASIBILITY OF BOUNDARY-LAYER CONTROL BY TANGENTIAL BLOWING FOR SUPPRESSION OF SIDE VENTILATION ON BASE-VENTED HYDROFOIL STRUTS
Available literature and experimental evidence are evaluated to determine the feasibility of active flow control by tangential blowing (circulation control) to suppress sudden side ventilation on base-vented struts on an 80-knot, 200-ton hydrofoil. The conclusion is that there is no evidence that the method will not work and there is some promising but not fully-relevant evidence in favor. Based on a very crude estimate of the possible effectiveness of such a method, the power requirements were estimated for a four-degree improvement in ventilation angle for a single strut of 5 x 10 square feet submerged planform area at 80 knots. Power consumption is about 900 HP, with a flow rate of 7 cubic ft/sec and a pressure differential of about 500 psi. A large fraction, if not all of the power requirement is likely to be recovered in reduced drag. A five-inch diameter circular duct is adequate to carry the flow with minimal losses and smaller sizes may be acceptable. It is recommended that a simple flow visualization experiment be performed using blowing in a reduced-pressure water channel. This would establish or overcome the objection of possible adverse effects of cavitation on the technique.
David Taylor Naval Ship R&D CenterShip Performance Department
Bethesda, MD United States 20084
- Rothblum, R S
- Publication Date: 1975-6
- Pagination: 19 p.
- TRT Terms: Boundary layer; Hydrofoils; Struts; Ventilation systems
- Old TRIS Terms: Boundary layer stability; Ventilated hydrofoils
- Subject Areas: Marine Transportation; Vehicles and Equipment;
- Accession Number: 00127582
- Record Type: Publication
- Source Agency: National Technical Information Service
- Report/Paper Numbers: SPD-625-01 Final Rpt.
- Files: TRIS
- Created Date: Nov 18 1975 12:00AM