Propeller Flow Field Mapping of Model 5415 Using 3-Component Laser Doppler Velocimetry
2005
Chesnakas, Christopher | Ratcliffe, Toby
Subsurface velocities were obtained on Model 5415 using a three-component Laser Doppler Velocimetry System. Data were obtained for the model running at a Froude number of 0.28, which corresponds to a full scale ship speed of 20 knots. Measurements were performed in three planes, x/L = 0.9367 (propelled), x/L = 0.9453 (unpropelled), and x/L = 0.9603 (propelled and unpropelled). A detailed uncertainty analysis was performed. The dominant source of uncertainty is the precision uncertainty due to the long period fluctuations in the flow. Over most of the flow field, the turbulence is low, and the uncertainty in any velocity component is less than 0.8% of U. In high turbulence regions of the flow, such as the hull or propulsor wakes, the uncertainty can increase to 2.5% of U. Both axial velocities and rms velocities are presented for each of the measurement planes. The effect of the propeller on the flow at the farthest downstream measurement plane is quantified.
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