Integration of autocad with laser doppler anemometry (LDA)

Laser Doppler Anemometry (LDA) is a powerful tool for non-intrusive, single point flow measurements. The limitation of probing only one point in the flow at any one time requires costly hardware to traverse what is already expensive LDA equipment. Even with high investments in capital cost, it is never that flexible to define traverses to scan a flow field, nor automate the driving of a traverse system to implement them, or interactively and conveniently visualise the measured results. In this paper, the subject flow field under study was the flow round the complex boundaries of the cones of a drill bit used in the oil industry. To overcome the difficulties of traversing, CAD/CAM techniques were employed which are standard for use in manufacturing. 'AutoCad' was used to draw, visualise and interactively choose measuring stations of the complicated 3-D flow domain. Downloading data automatically through a suitable software interface, the traverse hardware was driven as if it was a standard Computer Numerically Controlled (CNC) machine. The LDA measurements themselves were up-loaded back to the CAD environment to offer a most flexible way to visualise the flow.