PIV Measurement of The Flow Field of A High-Speed Planing Craft with Stern Tunnel

Abstract

The stern tunnel is commonly used for high-speed planing crafts. However, it is only few studies that have been conducted for the performance of stern tunnel particularly for the flow field. Accordingly, flow field measurement of stern tunnel is required particularly for study the flow pattern and velocity component profile due to the stern tunnel. 2D moving PIV system have been developed in this thesis project following to measure the flow field of stern tunnel where the PIV measurement is used to provide the flow field measurement result comparing with other experiment fluid dynamic methods. In this thesis project, a moving PIV system is installed on the carrier of a towing tank and moving with the ship model. The measurement system provide both streamwise and cross streamwise planes. A 1:14 scale ship model with stern tunnel design is applied at towing speed 0.69 m/s. The ship model and PIV system, particularly the traverse and optical component, have been developed and modified successfully to overcome the blocking accessible of the image and laser light path due to the characteristics of high-speed planing craft and typical curvy shape of the stern tunnel. The methodologies and associated techniques for moving PIV measurement in a large towing tank are described in detail. Any discrepancies prior and during experiments are also identified and explained reasonably. Velocity component profiles and flow pattern as the result of the studies are presented well and compared with other result studies, i.e. LDV measurement and CFD simulation. The experiment results and analysis confirm previous studies’ assumptions and results about the present of stern tunnel that could decrease the defect velocity profile prior the propeller region and increase the inflow of propeller region.