Hydrodynamic coefficient estimation for TLP and spar structures

Research papers at previous OMAE conferences by Thiagarajan and Troesch [4, 5] described forced oscillation model tests using a 0.45-m-dia cylinder and a 0.6-m-disk appended to the cylinder base for drag augmentation. Scaling laws were proposed based on a component scaling concept for extrapolation o f full-scale added mass and damping coefficients. The present work further verifies the scaling methodology by presenting and discussing results on sm aller models-cylinder and disk of diameters 0.15 m and 0.19 m, respectively . The dimensions of the smaller models are typical of more complex offshore platform models tested in scale 1:50 to 1:75 design sea states. The hydrod ynamic coefficients of the cylinder and of the disk are estimated individua lly, and component-scaling methodology is examined. Physics-based arguments for the differences in force coefficients of the configurations are discus sed: flow around the cylinder, flow around the disk, and flow around the co mposite structure. The analysis results from force measurements and flow vi sualization conducted during forced oscillation experiments. Further, diffi culties in maintaining accuracy with the smaller models are examined. [S089 2-7219(00)00202-8].