Air sheet lubrication for drag reduction of solid bodies in fast flowing fluids

MSc graduation project of Arjan de Jonge
Location: Lab. for Aero & Hydrodynamics
Supervisor: R. Delfos
Start of project: March 2010

Project description:

The project is about the cavitation tunnel at Maritime Engineering which is planned to be used for research for air lubrication for ships. The research consists of two parts. At first the design part. Since the old cavitation tunnel does not meet the current requirements which are needed to do the air lubrication experiments (and other current experiments) it has to be modified. The shape has to be changed taking into account the boundary layer displacement, the required constant central velocity and the pressure gradient over the test section. Furthermore, additional measurement equipment is needed for measuring the velocity, pressure, shear stress on an (air lubricated) test plate. This modification of the cavitation tunnel is done by following literature of what is commonly used and since some solutions are not common knowledge experiments on scale models will be done. This process includes the investigation of what is needed, determination of the function(s) of the cavitation tunnel, the generation of possible solutions for fulfilling these functions, the selection procedure of the possible solutions and combining these possible solutions to concepts out of which finally the best concept can be chosen. With the requirements, the found concept of solutions and supporting drawings a contractor can be chosen. Since the (closed loop) cavitation tunnel needs a de-aerator for preventing that the injected air, which is used for air sheet lubrication experiments, circulates back into the test section, a study is done on the behaviour of air bubbles in channels. Bubble sizes, bubble rising length are keywords in this study and connects the first part with the second part. Secondly, the research part. There is no subject known yet. If the modification process is fast enough, it will probably be about some preliminary testing on the distribution of air bubbles and velocity-, pressure profiles on the (air lubricated) test plate which will be suited with "trip-plates' with different geometry.

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