University of Twente Student Theses


Crossing Obstacles

Cijsouw, J.W. (2016) Crossing Obstacles.

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Abstract:In the group of flow control at the department of aeronautics and astronautics at the Zhejiang University in Hangzhou, China. The physical phenomena behind cavitational flows are studied intensively by numerical simulations and by experiments. When cavitation occurs, water will evaporate due to a (locally) lowered pressure. During this training period, the cavitational flow on top of a hydrofoil in the Zhejiang water tunnel was experimentally studied. At the top surface of the foil, small obstacles were attached at various locations along the hydrofoil’s chord. Purpose of the obstacles was to reduce the cloud cavity volume and to change the shedding frequency. During the experiments high speed images were made from the top and the side of the tunnel’s measurement section. A matlab script was written to obtain the pixel intensity from the top view images and the cavity height from the sight view images. The resulting information is combined to calculate the cavity volume. The results obtained by matlab and directly obtained from the high speed videos indicate that the cavity volume is reduced. The location for optimal cavity reduction was found. Furthermore, the highly periodic behavior of cavity shedding was reduced, for some obstacles no periodic behavior was visible any more.
Item Type:Internship Report (Master)
Zheijang University, China
Faculty:ET: Engineering Technology
Subject:52 mechanical engineering
Programme:Mechanical Engineering MSc (60439)
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