Investigation of Drag Reduction by Boundary Layer Ingestion, Base Blowing, Base Ventilation and Free Surface Depression

This research effort will pursue four key methods of frictional drag reduction identified by Navatek, Ltd. under a prior CEROS MIDFOIL grant as supporting technologies to achieve a very high speed (70-100 knots) large (5,000-10,000 ton) ship. Under this grant, Navatek conceptualized a high-speed ship buoyantly and dynamically supported by high lift-to drag, high operating Froude number (F>1.2) lifting bodies operating in the presence of the free surface. This concept emerged from Navatek's research on SLICE and MIDFOIL technology, including large demonstrators. The four methods are 1) boundary layer ingestion to recover the momentum in the boundary layer; 2) base blowing to reduce the surface area of the submerged hull after bodies, eliminate control surface appendages and alter the pressure distribution over the body; 3) base venting to reduce the surface area of the strut afterbodies; 4) high lift-to-drag deltoid lifting body strut appendages to create a solitary wave to unwet strut appendages. Numerical analysis using validated CFD programs will develop concepts to achieve the highest lift-to-drag performance. The resultant designs can be tested at large model scale using Navatek-owned test craft, including the SLICE and MIDFOIL craft.