Measurement of flow-induced pressures on the surface of a model in a flow visualization water tunnel

Sie sind hier: Homepage > Suche

Measurement of flow-induced pressures on the surface of a model in a flow visualization water tunnel

Erm, L.P.

Complex flow patterns around models can often be visualized in greater detail in water tunnels than they can in wind tunnels. In water tunnels, different techniques can be used to visualize the flow patterns, including using dyes emitted from ports strategically located on a model, using hydrogen bubbles generated at selected regions on a model, and by illuminating fluorescent dyes in the flow using lasers. Flow visualization studies in water tunnels can give an insight into the complex vortical flow behaviour around models, enabling researchers to obtain an understanding of the basic fluid dynamics of the flows. Flow visualization is a useful tool when undertaking developmental work in water tunnels. Such testing in water tunnels is appealing since models are relatively cheap to build and modify, compared with wind tunnel models, so that experiments can be undertaken and results evaluated quickly. Flow-induced pressures were measured on the surface of a delta wing in a flow visualization water tunnel, and at the same time the vortical flow over the wing was visualized using dye. For a free-stream velocity of 0.1 m/s used in the experiments, the pressures were small (less than 15 Pa). This is believed to be the first time that flow-induced pressures have been measured in a water tunnel at such a low velocity. Measured pressure distributions can now be properly interpreted in terms of observed detailed flow patterns, without having to undertake complementary wind tunnel experiments to measure model loading.