1. Why visualizations?

To understand and control a flow, it is often necessary to combine a theoretical approach with experimental analysis. After a long period during which experience was king, due to the absence or weakness of computing resources, came the era of the "digital" due to the explosion of computer systems. The spectacular aspect of modeling has, however, led some users to become disillusioned, by concealing the importance of physical phenomena, which were sometimes poorly appreciated at the outset. Today, physicists and engineers agree that a good model is only as good as its experimental validation.

Among the countless experimental techniques, visualization occupies a special place: first of all, since light acts as a sensor, the disturbance caused to the fluid is small, even negligible. At most, if we're not careful, a little parasitic energy can be introduced in the form...