Optimization of a water table to study aerodynamic phenomena

Abstract

The goal of this thesis is to optimize the water table to visualize shock waves and vortices in the water flow. We can divide this goal in two. The first goal of this thesis is the adaptation of the water table of Erasmushogeschool Brussel in order to have a laminar flow (and also to control the speed of the flow) to create the phenomena, when a solid body is placed on the table of boundary layer, vortices, and shock waves. The second goal is to visualize these phenomena in the best possible way. The first step was to do a theoretical study of the phenomena that we wanted to create in our table and the laminar flow. So in this thesis are explained the phenomena of boundary layer, shock waves and vortices; also a study of what a laminar flow is was made. After having obtained this theoretical background, seven experiments were made in order to get the first goal of this thesis; we had to define a design for the water table which reached the first goal of the thesis. After each experiment we got some conclusions that helped us to choose the next experiment to do and the best way to improve the water table. The experiments were made with one and with both pumps working. After having chosen the best design for our table, we studied two possible alternative designs for the water table. The first one consists in the installation of an upper plate on the test area for a better control of the speed of the flow. The second one is a completely new water table design where the entrance to the test area is adjustable and it controls the speed of the flow. The shock waves could be visualized in a better way and the boundary layer is not viewable. Four methods of visualization are studied in the final part of this thesis in order to get the second goal. These are Dye injection, air or hydrogen bubbles injection, aluminium particles (to see the boundary layer) and solid particles. The last one was experimented on our table by spreading rice grains on it. This thesis can be used as a guide for who works in the future on this table, so he can choose the best system of visualization according to his needs and budget; it is also important to write some alternative water tables for the future needs, as it has been done. The design chosen after the experiments has been installed in the table; the wood sheet with the tracks can be removed when we work with both pumps switched on.