Bow Wave Measurements of the R/V Athena I: 2004

Abstract : The bow wave of the R/V Athena I was quantified in calm water and in a Sea State 3 using a Quantitative Flow Visualization (QViz) system developed at the Naval Surface Warfare Center, Carderock Division. This effort represents the second time that the QViz system has been taken aboard the research vessel Athena. These experiments were performed in both the protected waters of St. Andrews Bay (Panama City, FL) and in the Gulf of Mexico. The data was collected over a five day period from May 17-21, 2004. The Athena was operated at six speeds; 2 knots (1.0m/s), 6 knots (3.1 m/s), 9 knots (4.6m/s), 10.5 knots (5.4m/s), 12 knots (6.2m/s) and 13.9 knots (7.2 m/s), corresponding to Froude numbers based on waterline length (47m) of 0.05, 0.14, 0.21, 0.24, 0.28, and 0.32 respectively. Data were collected at seven axial locations, in 1-foot (0.3m) intervals, along the bow. Predictions from the non-linear potential flow code, DAS BOOT, are compared to the experimental data. In addition to the QViz data, video cameras captured the flow around the hull at six camera locations. Additional data was obtained by other cooperating research groups and included laser altimeter measurements of the stern wake, conductivity probes to measure the void fraction in the wake of the ship, a particle/bubble imaging system to determine bubble size distributions, a defocusing bubble imaging system, and a high speed video system.