Perpustakaan Digital ITB

An image processing code was developed to measure velocity fields from a given set of particle images obtained from digital particle image velocimetry (DPIV) experiments. The developed code implements continuous window shifting method and window deformation method in order to improve its accuracy and anticipate high velocity gradient. Several quantitative evaluations were performed by using artificial images to assess the developed code and the result shows that the developed code has higher accuracy than conventional DPIV image processing code. Several qualitative evaluations were also performed by using real particle images to assess its ability to handle imperfection that exist in real particle images (the existence of noise, unbalance brightness, and low image contrast) and the result is satisfactory. As a complement for the image processing code, force determination code were also developed to measure fluid dynamics force acting on a body inside given flow field from given DPIV image processing result. The code was validated by using computational fluid dynamic (CFD) simulation and the result is satisfactory. The code was also compared with other force determination method and similar trends of force history were found. After both the image processing code and the force determination code has been successfully developed and evaluated, DPIV experiments were conducted to investigate flow around flapping wing in a continuous hovering flight by using the developed codes. Two flapping modes were investigated with three different Reynolds numbers. It was found that different flapping modes lead to different vortex formation and interaction while different Reynolds number affects vortex movement and dissipation. Correlation between vorticity field and fluid dynamic force at a time instances were also observed and discussed.