Abstract:
This thesis deals with hydrofoils, appendages which are a growing trend in
yacht design and aimed at alleviating boats (this reduces the wetted area and
therefore the drag). This thesis acknowledges the research previously done
relating to hydrofoils and the testing of hydrofoils from the 1900's until now,
from a military and sailing point of view. It goes through the methodology
used to extract lift and drag data from tank testing in Cran field University. It
goes through the approach to design a test process to extract consistent results
from different foils in later stages. The works also details the manufacturing
of the rig to test a hydrofoil in near surface conditions: the pro file studied is
the NACA 4412, the submergence ranges from 2.5 chords to 0.1 chords, the
angle of attack ranges from 10 to -1 degrees and Reynolds Number ranging
from 1500000 to 910000 (0.5 to 3.0 m/s). The resulting data showed that lift
decreased as the foil got closer to the free surface. With signifi cant effects
being seen from a submergence of 1 chord. This project also points outs the
limitations of tank testing and the effects of side struts holding the hydrofoil.
